CN115136443A

CN115136443A - Three-bridge-arm topology device, control method, inversion system and uninterruptible power supply system

Info

Publication number: CN115136443A
Application number: CN202080096876.4A
Authority: CN
Inventors: 罗峰
Original assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd; Guangzhou Shikun Electronic Technology Co Ltd
Current assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd; Guangzhou Shikun Electronic Technology Co Ltd
Priority date: 2020-05-22
Filing date: 2020-11-11
Publication date: 2022-09-30
Also published as: WO2021232706A1

Abstract

A three-bridge arm topology device, a control method, an inversion system and an uninterruptible power supply system are provided, the three-bridge arm topology device realizes the charging or discharging of a battery pack through a multiplexing voltage conversion circuit, and the battery pack can be charged without additionally adding a charger. In addition, the voltage conversion circuit and the three-arm circuit are both involved in operation, i.e., all devices of the three-arm topology device are involved in operation, no matter in the external power supply mode or the battery power supply mode. When the three-bridge-arm topological device is applied to a battery low-voltage large-current UPS system or an inverter system, the device reuse rate of the system can be improved, the device design redundancy is avoided, and the cost of the battery low-voltage large-current UPS system or the inverter system is further reduced.

Description

Three-bridge-arm topology device, control method, inversion system and uninterruptible power supply system

The present application claims priority of chinese patent applications filed on 22/05/2020/202010444170.4 under the name "three-arm topology device, control method, and uninterruptible power supply system", and also on 22/05/2020/202020885385.5 under the name "three-arm topology device and uninterruptible power supply system", the entire contents of which are incorporated herein by reference.

Technical Field

The embodiment of the application relates to a power supply technology, in particular to a three-bridge-arm topology device, a control method, an inverter system and an uninterruptible power supply system.

Background

The power supply system of low voltage and large current of the battery refers to a power supply system which adopts a small number of batteries as a battery pack. When the power supply system uses the battery pack to supply power to a load, the power supply system can output electric energy with low voltage and large current. At present, common Power Supply systems with low voltage and large current of batteries include Uninterruptible Power Supply (UPS) systems, inverter systems, and the like.

Since the number of battery cells in the battery pack used in the low-voltage high-current battery power supply system is small, the low-voltage high-current battery power supply system is widely used. However, the current power supply system with low voltage and large current of the battery has low device reuse rate, which results in high cost of the power supply system with low voltage and large current of the battery.

Disclosure of Invention

The embodiment of the application provides a three-bridge-arm topology device, a control method, an inverter system and an uninterruptible power supply system, and is used for solving the technical problem that the device reuse rate of the conventional battery low-voltage large-current UPS system is low. The technical scheme is as follows:

in a first aspect, an embodiment of the present application provides a three-arm topology device, where the three-arm topology device includes: the device comprises a battery pack, a voltage conversion circuit and a three-bridge arm circuit; the three-bridge arm circuit includes: the bridge comprises a first bridge arm, a second bridge arm, a third bridge arm, a first inductor, a second inductor, a direct current bus capacitor and a first capacitor; the first bridge arm comprises a first switching tube and a second switching tube which are connected in series; the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series; the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series;

The first bridge arm, the second bridge arm, the third bridge arm and the direct current bus capacitor are connected in parallel between a positive output end and a negative output end of a bus; the midpoint of the first bridge arm is connected with the first end of the first inductor, and the second end of the first inductor is used as a positive voltage input end of the three-bridge-arm topological device; the midpoint of the second bridge arm or the negative output end of the bus is used as a negative voltage input end of the three-bridge-arm topological device; the middle point of the third bridge arm is connected with the first end of the second inductor, the second end of the second inductor is connected with the first end of the first capacitor, the second end of the first capacitor is connected with the middle point of the second bridge arm, the first end of the first capacitor is a first output end of the three-bridge-arm topological device, the second end of the first capacitor is a second output end of the three-bridge-arm topological device, and the first output end and the second output end are both connected with a load;

the positive electrode of the battery pack is connected with the first end of the voltage conversion circuit, the negative electrode of the battery pack is connected with the second end of the voltage conversion circuit, the third end of the voltage conversion circuit is connected with the positive output end of the bus, the fourth end of the voltage conversion circuit is connected with the negative output end of the bus, the first end of an external power supply is connected with the positive voltage input end, and the second end of the external power supply is connected with the negative voltage input end;

The voltage conversion circuit is used for charging the battery pack in an external power supply mode; in a battery powered mode, discharging the battery pack.

In a second aspect, an embodiment of the present application provides an uninterruptible power supply system, where the system includes: an external power supply, a load, and a three-bridge arm topology as described in the first aspect; the first end of the external power supply is connected with the positive voltage input end of the three-bridge arm topology device, the second end of the external power supply is connected with the negative voltage input end of the three-bridge arm topology device, and the first output end and the second output end of the three-bridge arm topology device are both connected with the load.

In a third aspect, an embodiment of the present application provides an uninterruptible power supply system, where the system includes: a first external power supply, a second external power supply, a load, and a three-bridge arm topology apparatus as described in the first aspect; the first end of the first external power supply source is connected with a first positive voltage input end of the three-bridge arm topology device, the second end of the first external power supply source is connected with a first negative voltage input end of the three-bridge arm topology device, the first end of the second external power supply source is connected with a second positive voltage input end of the three-bridge arm topology device, the second end of the second external power supply source is connected with a second negative voltage input end of the three-bridge arm topology device, and a first output end and a second output end of the three-bridge arm topology device are both connected with the load.

In a fourth aspect, an embodiment of the present application provides a method for controlling a three-arm topology device, where in the three-arm topology device in the first aspect, when the switch is in an external power supply mode, the voltage conversion circuit is controlled to charge the battery pack, and when in a battery power supply mode, the voltage conversion circuit is controlled to discharge the battery pack, if the switch includes: the circuit comprises a first switch, a second switch and a balance component; and the third end of the voltage conversion circuit is connected with the fixed end of the first switch, the first selection end of the first switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, the second selection end of the first switch is connected with the positive voltage input end, the first end of the second switch is connected with the first end of the external power supply, the second end of the second switch is connected with the positive voltage input end, and the fourth end of the voltage conversion circuit is connected with the negative output end of the bus, so that the three-bridge-arm topology device can be controlled by the following method, and the method comprises the following steps: when in an external power supply mode, controlling the fixed end of a first switch to be communicated with a first selection end of the first switch, and closing a second switch; and when the battery is in a battery power supply mode, the fixed end of the first switch is controlled to be communicated with the second selection end of the first switch, and the second switch is disconnected.

Optionally, if the balance component is a resistor, the switch further includes: a third switch; the third end of the voltage conversion circuit is connected with the first end of the third switch, and the second end of the third switch is connected with the positive output end of the bus; alternatively, the third switch is connected in parallel with the resistor. Then in this implementation, the three-arm topology device may be controlled by a method comprising: in an external power supply mode, controlling a fixed end of a first switch to be communicated with a first selection end of the first switch, closing a second switch, and controlling a third switch to be closed when a voltage difference value between a bus and a voltage conversion circuit of the three-bridge-arm topological device is smaller than or equal to a preset threshold value; and when in a battery power supply mode, the fixed end of the first switch is controlled to be communicated with the second selection end of the first switch, and the second switch and the third switch are disconnected.

In a fifth aspect, an embodiment of the present application provides a method for controlling a three-arm topology device, where in the three-arm topology device in the first aspect, when the switch is in an external power supply mode, the voltage conversion circuit is controlled to charge the battery pack, and when in a battery power supply mode, the voltage conversion circuit is controlled to discharge the battery pack, if the switch includes: the circuit comprises a first switch, a second switch and a balance component; and the third end of the voltage conversion circuit is connected to the first end of the first switch and the first selection end of the second switch, the second end of the first switch is connected to the first end of the balance element, the second end of the balance element is connected to the positive output end of the bus, the second selection end of the second switch is connected to the first end of the external power supply, the fixed end of the second switch is connected to the positive voltage input end, and the fourth end of the voltage conversion circuit is connected to the negative output end of the bus, so that the three-bridge-arm topology device can be controlled by the following method, and the method includes: when in an external power supply mode, controlling the first switch to be closed, wherein the fixed end of the second switch is communicated with the second selection end of the second switch; and when the battery is in a power supply mode, the first switch is controlled to be switched off, and the fixed end of the second switch is communicated with the first selection end of the second switch.

Optionally, the balance component is a resistor, and the switch further includes: a third switch; the third end of the voltage conversion circuit is connected with the first end of the third switch, and the second end of the third switch is connected with the positive output end of the bus; alternatively, the third switch is connected in parallel with the resistor. Then in this implementation, the three-arm topology device may be controlled by a method comprising: when the power supply device is in an external power supply mode, controlling a first switch to be closed, communicating a fixed end of a second switch with a second selection end of the second switch, and controlling a third switch to be closed when a voltage difference value between a bus and a voltage conversion circuit of the three-bridge-arm topological device is smaller than or equal to a preset threshold value; and when the battery is in a power supply mode, the third switch and the first switch are controlled to be disconnected, and the fixed end of the second switch is communicated with the first selection end of the second switch.

In a sixth aspect, an embodiment of the present application provides a method for controlling a three-arm topology device, where in the three-arm topology device in the first aspect, when the switch is in an external power supply mode, the voltage conversion circuit is controlled to charge the battery pack, and when in a battery power supply mode, the voltage conversion circuit is controlled to discharge the battery pack, if the switch includes: the first switch, the second switch, the third switch and the balance component; the third terminal of the voltage converting circuit is connected to the first terminal of the first switch and the first terminal of the third switch, respectively, the second terminal of the first switch is connected to the positive voltage input terminal, the first terminal of the second switch is connected to the first terminal of the external power supply, the second terminal of the second switch is connected to the positive voltage input terminal, the second terminal of the third switch is connected to the first terminal of the balancing component, the second terminal of the balancing component is connected to the positive output terminal of the bus, and the fourth terminal of the voltage converting circuit is connected to the negative output terminal of the bus, so that the three-bridge topology apparatus can be controlled by the following method, wherein the method comprises: in the external power supply mode, the first switch is controlled to be switched off, and the second switch and the third switch are controlled to be switched on; and in the battery power supply mode, the first switch is controlled to be closed, and the second switch and the third switch are controlled to be opened.

Optionally, the balance component is a resistor, and the switch further includes: a fourth switch; the third end of the voltage conversion circuit is connected with the first end of the fourth switch, and the second end of the fourth switch is connected with the positive output end of the bus; alternatively, the fourth switch is connected in parallel with the resistor. Then in this implementation, the three-arm topology device may be controlled by a method comprising: in an external power supply mode, the first switch is controlled to be switched off, the second switch and the third switch are controlled to be switched on, and when the voltage difference value between the bus and the voltage conversion circuit of the three-arm topology device is smaller than or equal to a preset threshold value, the fourth switch is controlled to be switched on and off; and in a battery power supply mode, the first switch is controlled to be closed, and the second switch, the third switch and the fourth switch are controlled to be opened.

In a seventh aspect, an embodiment of the present application provides a method for controlling a three-arm topology device, where when a voltage conversion circuit in the three-arm topology device in the first aspect forms a bidirectional DCDC topology by multiplexing a second arm of a three-arm circuit and a bus capacitor, the three-arm topology device may be controlled by the following method, where the method includes:

In the first stage of the external power supply mode, the second switching tube, the fourth switching tube, the fifth switching tube and the eleventh switching tube are controlled to be conducted;

in a second stage of the external power supply mode, the second switch tube, the fourth switch tube, the fifth switch tube and the twelfth switch tube are controlled to be conducted;

in a third stage of the external power supply mode, controlling the fourth switching tube, the fifth switching tube and the eleventh switching tube to be conducted;

in a fourth stage of the external power supply mode, the fourth switching tube, the fifth switching tube and the twelfth switching tube are controlled to be conducted;

in a fifth stage of the external power supply mode, the second switching tube, the fourth switching tube, the sixth switching tube and the eleventh switching tube are controlled to be conducted;

in a sixth stage of the external power supply mode, the second switching tube, the fourth switching tube, the sixth switching tube and the twelfth switching tube are controlled to be conducted;

in a seventh stage of the external power supply mode, controlling the fourth switching tube, the sixth switching tube and the eleventh switching tube to be conducted;

in an eighth stage of the external power supply mode, controlling the fourth switching tube, the sixth switching tube and the twelfth switching tube to be conducted;

In a ninth stage of the external power supply mode, controlling the conduction of a first switch tube, a third switch tube, the sixth switch tube and the twelfth switch tube;

in a tenth stage of the external power supply mode, the first switch tube, the third switch tube, the sixth switch tube and the eleventh switch are controlled to be conducted;

in an eleventh stage of the external power supply mode, the third switching tube, the sixth switching tube and the twelfth switching tube are controlled to be conducted;

in a twelfth stage of the external power supply mode, the third switching tube, the sixth switching tube and the eleventh switching tube are controlled to be conducted;

in a thirteenth stage of the external power supply mode, the first switching tube, the third switching tube, the fifth switching tube and the twelfth switching tube are controlled to be conducted;

in a fourteenth stage of the external power supply mode, the first switch tube, the third switch tube, the fifth switch tube and the eleventh switch tube are controlled to be conducted;

in a fifteenth stage of the external power supply mode, the third switching tube, the fifth switching tube and the twelfth switching tube are controlled to be conducted;

In a sixteenth stage of the external power supply mode, the third switching tube, the fifth switching tube and the eleventh switching tube are controlled to be conducted;

in the first stage of the battery power supply mode, controlling the fourth switching tube, the fifth switching tube, the seventh switching tube, the tenth switching tube and the twelfth switching tube to be conducted;

in a second stage of the battery power supply mode, controlling the fourth switching tube, the fifth switching tube, the eighth switching tube, the ninth switching tube and the eleventh switching tube to be conducted;

in a third stage of the battery power supply mode, controlling the fourth switching tube, the sixth switching tube, the seventh switching tube, the tenth switching tube and the twelfth switching tube to be conducted;

in a fourth stage of the battery power supply mode, controlling the fourth switching tube, the sixth switching tube, the eighth switching tube, the ninth switching tube and the eleventh switching tube to be conducted;

in a fifth stage of the battery power supply mode, controlling a third switching tube, the sixth switching tube, the seventh switching tube, the tenth switching tube and the twelfth switching tube to be conducted;

in a sixth stage of the battery power supply mode, the third switching tube, the sixth switching tube, the eighth switching tube, the ninth switching tube and the eleventh switching tube are controlled to be conducted;

In a seventh stage of the battery power supply mode, the third switching tube, the fifth switching tube, the seventh switching tube, the tenth switching tube and the twelfth switching tube are controlled to be conducted;

and in an eighth stage of the battery power supply mode, the third switching tube, the fifth switching tube, the eighth switching tube, the ninth switching tube and the eleventh switching tube are controlled to be conducted.

In an eighth aspect, an embodiment of the present application provides a three-arm topology device, where the three-arm topology device includes: the device comprises a battery pack, a voltage conversion circuit and a three-bridge arm circuit; the three-bridge arm circuit includes: the bridge comprises a first bridge arm, a second bridge arm, a third bridge arm, a direct current bus capacitor and a filter; the first bridge arm comprises a first switching tube and a second switching tube which are connected in series; the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series; the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series;

the first bridge arm, the second bridge arm, the third bridge arm and the direct current bus capacitor are connected in parallel between a positive output end and a negative output end of a bus; the middle point of the second bridge arm and the middle point of the third bridge arm are both connected with the filter; the positive electrode of the battery pack is connected with the first end of the voltage conversion circuit, the negative electrode of the battery pack is connected with the second end of the voltage conversion circuit, the third end and the fourth end of the voltage conversion circuit are both connected with the three-bridge-arm circuit, the filter is provided with a first external connecting end of the three-bridge-arm topological device and a second external connecting end of the three-bridge-arm topological device, and the filter is connected with a load in a battery power supply mode;

The voltage conversion circuit discharges the battery pack in the battery power mode.

In a ninth aspect, an embodiment of the present application provides an inverter system, including: a load, and a three-arm topology as described in the eighth aspect; in a battery powered mode, the first external connection end and the second external connection end of the three-arm topology device are both connected to the load.

In a tenth aspect, an embodiment of the present application provides a method for controlling a three-arm topology device, where in the eighth aspect, when the three-arm topology device forms a bidirectional DCDC topology through a voltage conversion circuit, a first arm of a three-arm circuit, and a bus capacitor, the three-arm topology device may be controlled by the following method, where the method includes:

in the first stage of the battery power supply mode, the second switch tube, the eighth switch tube, the ninth switch tube and the eleventh switch tube are controlled to be conducted;

in the second stage of the battery power supply mode, the first switching tube, the seventh switching tube, the tenth switching tube and the twelfth switching tube are controlled to be conducted;

in the first stage of the battery charging mode, the second switch tube and the eleventh switch tube are controlled to be conducted;

And in the second stage of the battery charging mode, the first switching tube and the twelfth switching tube are controlled to be conducted.

In an eleventh aspect, an embodiment of the present application provides a method for controlling a three-bridge-arm topology device, where in the eighth aspect, when the three-bridge-arm topology device forms a bidirectional DCDC topology by a voltage conversion circuit, a first bridge arm, a second bridge arm, and a bus capacitor, the three-bridge-arm topology device may be controlled by the following method, where the method includes:

in the first stage of the battery power supply mode, the second switching tube, the fourth switching tube, the fifth switching tube, the seventh switching tube and the tenth switching tube are controlled to be conducted;

in the second stage of the battery power supply mode, controlling the conduction of a first switch tube, the fourth switch tube, the fifth switch tube, an eighth switch tube and a ninth switch tube;

in a third stage of the battery power supply mode, controlling the second switch tube, the fourth switch tube, the sixth switch tube, the seventh switch tube and the tenth switch tube to be conducted;

in a fourth stage of the battery power supply mode, controlling the first switch tube, the fourth switch tube, the sixth switch tube, the eighth switch tube and the ninth switch tube to be conducted;

In a fifth stage of the battery power supply mode, the first switching tube, the third switching tube, the sixth switching tube, the eighth switching tube and the ninth switching tube are controlled to be conducted;

in a sixth stage of the battery power supply mode, the first switching tube, the second switching tube, the third switching tube, the sixth switching tube, the seventh switching tube and the tenth switching tube are controlled to be conducted;

in a seventh stage of the battery power supply mode, controlling the first switching tube, the third switching tube, the fifth switching tube, the eighth switching tube and the ninth switching tube to be conducted;

in an eighth stage of the battery power supply mode, controlling the first switching tube, the second switching tube, the third switching tube, the fifth switching tube, the seventh switching tube and the tenth switching tube to be conducted;

in the first stage of the battery charging mode, controlling the first switch tube, the fourth switch tube and the sixth switch tube to be conducted;

in a second stage of the battery charging mode, the second switch tube, the fourth switch tube and the sixth switch tube are controlled to be conducted;

in a third stage of the battery charging mode, controlling the first switch tube, the fourth switch tube and the fifth switch tube to be conducted;

In a fourth stage of the battery charging mode, controlling the second switch tube, the fourth switch tube and the fifth switch tube to be conducted;

in a fifth stage of the battery charging mode, controlling the second switching tube, the third switching tube and the fifth switching tube to be conducted;

in a sixth stage of the battery charging mode, the first switching tube, the third switching tube and the fifth switching tube are controlled to be conducted;

in a seventh stage of the battery charging mode, the second switching tube, the third switching tube and the sixth switching tube are controlled to be conducted;

and in an eighth stage of the battery charging mode, the first switching tube, the third switching tube and the sixth switching tube are controlled to be conducted.

The three-bridge-arm topology device, the control method, the inverter system and the uninterruptible power supply system provided by the embodiment of the application realize the charging or discharging of the battery pack through the multiplexing voltage conversion circuit, and the battery pack can be charged without additionally adding a charger. In addition, whether the battery pack is charged or discharged, the voltage conversion circuit and the three-arm circuit are all involved in operation, that is, all devices of the three-arm topology device are involved in operation. When the three-bridge-arm topological device is applied to a battery low-voltage large-current UPS system or an inverter system, the device reuse rate of the system can be improved, the device design redundancy is avoided, and the cost of the battery low-voltage large-current UPS system or the inverter system is further reduced.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to the drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a battery low-voltage high-current UPS system provided in the prior art;

fig. 1A is a schematic structural diagram of a battery low-voltage large-current inverter system provided in the prior art;

fig. 2 is a first schematic diagram of a first three-arm topology device according to an embodiment of the present disclosure;

fig. 3 is a second schematic diagram of a first three-arm topology device according to an embodiment of the present disclosure;

fig. 4 is a schematic diagram of a second three-arm topology apparatus provided in the embodiments of the present application;

fig. 5 is a schematic diagram of a third bridge arm topology apparatus provided in an embodiment of the present application;

fig. 6 is a schematic diagram of a fourth three-bridge-arm topology apparatus provided in the embodiment of the present application;

fig. 7 is a schematic diagram of a fifth three-arm topology apparatus provided in the embodiments of the present application;

Fig. 8 is a first current schematic diagram of a fourth three-leg topology device provided in the embodiment of the present application in an external power supply mode;

fig. 9 is a current schematic diagram ii of a fourth three-leg topology device provided in the embodiment of the present application in an external power supply mode;

fig. 10 is a current schematic diagram three of a fourth three-leg topology device provided in the embodiment of the present application in an external power supply mode;

fig. 11 is a fourth current schematic diagram of a fourth three-leg topology device provided in the embodiment of the present application in an external power supply mode;

fig. 12 is a fifth current schematic diagram of a fourth three-leg topology device provided in the embodiment of the present application in a battery power supply mode;

fig. 13 is a current schematic diagram six of a fourth three-leg topology device according to the embodiment of the present application in a battery power supply mode;

fig. 14 is a schematic diagram of a sixth three-arm topology apparatus provided in an embodiment of the present application;

fig. 15 is a schematic diagram of a seventh three-arm topology apparatus provided in the embodiments of the present application;

fig. 16 is a schematic diagram of an eighth three-arm topology apparatus provided in an embodiment of the present application;

fig. 17 is a schematic diagram of a ninth three-arm topology apparatus provided in an embodiment of the present application;

fig. 18 is a schematic diagram of a tenth three-bridge-arm topology apparatus provided in an embodiment of the present application;

Fig. 19 is a schematic diagram of an eleventh three-bridge arm topology apparatus provided in an embodiment of the present application;

fig. 20 is a schematic diagram of a twelfth three-arm topology device according to an embodiment of the present application;

fig. 21 is a schematic diagram of a thirteenth three-leg topology device according to an embodiment of the present application;

fig. 22 is a schematic diagram of a fourteenth three-leg topology device according to an embodiment of the present application;

fig. 23 is a schematic diagram of a fifteenth three-bridge topology device provided in an embodiment of the present application;

fig. 24 is a schematic diagram of a sixteenth three-arm topology apparatus according to an embodiment of the present application;

FIG. 25 is a first schematic diagram illustrating a partial connection of a voltage converting circuit according to an embodiment of the present disclosure;

fig. 26 is a partial connection schematic diagram of a voltage conversion circuit according to an embodiment of the present disclosure;

fig. 27 is a third schematic diagram illustrating a partial connection of a voltage converting circuit according to an embodiment of the present application;

fig. 28 is a partial connection schematic diagram of a voltage converting circuit according to an embodiment of the present application;

fig. 29 is a partial connection schematic diagram of a voltage conversion circuit according to an embodiment of the present application;

fig. 30 is a schematic diagram illustrating a partial connection of a voltage converting circuit according to an embodiment of the present application;

fig. 31 is a schematic diagram illustrating a partial connection of a voltage converting circuit according to an embodiment of the present application;

Fig. 32 is a first schematic structural diagram of a first voltage conversion unit according to an embodiment of the present disclosure;

fig. 33 is a second schematic structural diagram of a first voltage conversion unit according to an embodiment of the present application;

fig. 34 is a third schematic structural diagram of a first voltage conversion unit according to an embodiment of the present application;

fig. 35 is a fourth schematic structural diagram of a first voltage conversion unit according to an embodiment of the present application;

fig. 36 is a schematic diagram of a seventeenth three-arm topology device according to an embodiment of the present application;

fig. 36A is a schematic diagram illustrating a partial connection of a voltage converting circuit according to an embodiment of the present application;

fig. 36B is a partial connection schematic diagram nine of a voltage conversion circuit according to an embodiment of the present application;

fig. 37 is a first current schematic diagram of a seventeenth three-arm topology device according to an embodiment of the present application in an external power supply mode;

fig. 38 is a schematic current diagram ii of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode;

fig. 39 is a current schematic diagram third of a seventeenth three-bridge-arm topology device according to the embodiment of the present application in an external power supply mode;

fig. 40 is a fourth current schematic diagram of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode;

Fig. 41 is a fifth current schematic diagram of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode;

fig. 42 is a sixth schematic current diagram of a seventeenth three-arm topology device according to an embodiment of the present application in an external power supply mode;

fig. 43 is a current schematic diagram seven of a seventeenth three-bridge-arm topology device according to an embodiment of the present application in an external power supply mode;

fig. 44 is a schematic current diagram eight of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode;

fig. 45 is a current schematic diagram nine illustrating a seventeenth three-arm topology device according to an embodiment of the present application in an external power supply mode

Fig. 46 is a current schematic diagram ten of a seventeenth three-bridge-arm topology device according to an embodiment of the present application in an external power supply mode;

fig. 47 is a schematic current diagram eleven of a seventeenth three-arm topology device according to an embodiment of the present application in an external power supply mode;

fig. 48 is a schematic current diagram twelve illustrating a seventeenth three-arm topology device according to an embodiment of the present application in an external power supply mode;

fig. 49 is a schematic current diagram thirteen illustrating a seventeenth three-leg topology device according to an embodiment of the present disclosure in an external power supply mode;

Fig. 50 is a schematic current diagram fourteen in an external power supply mode of a seventeenth three-arm topology device according to the embodiment of the present application;

fig. 51 is a schematic current diagram fifteen illustrating a seventeenth three-arm topology device according to an embodiment of the present application in an external power supply mode;

fig. 52 is a schematic current diagram sixteen illustrating a seventeenth three-arm topology device according to an embodiment of the present application in an external power supply mode;

fig. 53 is a first current schematic diagram of a seventeenth three-arm topology device according to the embodiment of the present application in a battery power supply mode;

fig. 54 is a schematic current diagram ii of a seventeenth three-arm topology device in a battery-powered mode according to the embodiment of the present application;

fig. 55 is a current schematic diagram third of a seventeenth three-arm topology device provided in the embodiment of the present application in a battery power supply mode;

fig. 56 is a fourth schematic current diagram of a seventeenth three-arm topology device according to the embodiment of the present application in a battery power supply mode;

fig. 57 is a fifth current schematic diagram of a seventeenth three-arm topology device in a battery-powered mode according to the embodiment of the present application;

fig. 58 is a sixth schematic current diagram of a seventeenth three-arm topology device according to an embodiment of the present application in a battery-powered mode;

Fig. 59 is a current schematic diagram seven of a seventeenth three-arm topology device in a battery-powered mode according to the embodiment of the present application;

fig. 60 is a schematic current diagram eight of a seventeenth three-arm topology device in a battery-powered mode according to the embodiment of the present application;

fig. 61 is a schematic diagram of an eighteenth three-leg topology device provided in the embodiment of the present application;

fig. 62 is a schematic diagram of a nineteenth three-bridge arm topology device according to an embodiment of the present application;

fig. 63 is a schematic diagram of a twentieth three-bridge-arm topology apparatus provided in an embodiment of the present application;

fig. 63A is a partial schematic connection diagram of a voltage converting circuit according to an embodiment of the disclosure;

fig. 63B is a schematic diagram illustrating a partial connection of a voltage converting circuit according to an embodiment of the present application;

fig. 64 is a first current schematic diagram of a twentieth three-bridge-arm topology device in a battery-powered mode according to the embodiment of the present application;

fig. 65 is a schematic current diagram of a twentieth three-bridge-arm topology device in a battery-powered mode according to the embodiment of the present application;

fig. 66 is a first schematic current diagram of a twentieth three-bridge-arm topology device according to the embodiment of the present application in a battery charging mode;

fig. 67 is a schematic current diagram ii of a twentieth three-bridge-arm topology device according to the embodiment of the present application in a battery charging mode;

FIG. 68 is a schematic diagram of a twenty-first three-arm topology device according to an embodiment of the present application;

fig. 68A is a schematic diagram illustrating a partial connection of a voltage converting circuit according to an embodiment of the disclosure;

fig. 68B is a schematic diagram of a partial connection diagram thirteen of a voltage conversion circuit according to an embodiment of the present disclosure;

fig. 69 is a schematic diagram of a twenty-second three-bridge arm topology apparatus according to an embodiment of the present application;

fig. 70 is a first current schematic diagram of a twenty-first three-arm topology device in a battery power supply mode according to the embodiment of the present application;

fig. 71 is a schematic current diagram of a twenty-first three-bridge topology device in a battery-powered mode according to the embodiment of the present application;

fig. 72 is a schematic current diagram of a twenty-first three-bridge topology device in a battery-powered mode according to the embodiment of the present application;

fig. 73 is a fourth schematic current diagram of a twenty-first three-bridge topology device in a battery-powered mode according to the embodiment of the present application;

fig. 74 is a fifth current schematic diagram of a twenty-first three-arm topology device in a battery power supply mode according to the embodiment of the present application;

fig. 75 is a sixth schematic current diagram of a twenty-first three-bridge topology device in a battery-powered mode according to an embodiment of the present application;

Fig. 76 is a seventh schematic current diagram of a twenty-first three-bridge topology device in a battery-powered mode according to an embodiment of the present application;

fig. 77 is a schematic current diagram eight of a twenty-first three-bridge topology device in a battery power supply mode according to the embodiment of the present application;

fig. 78 is a first schematic current diagram of a twenty-first three-bridge topology device in a battery charging mode according to an embodiment of the present application;

fig. 79 is a schematic current diagram ii of a twenty-first three-bridge topology device in a battery charging mode according to the embodiment of the present application;

fig. 80 is a schematic current diagram of a twenty-first three-bridge topology device in a battery charging mode according to the present application;

fig. 81 is a fourth schematic current diagram of a twenty-first three-bridge topology device in a battery charging mode according to the present application;

fig. 82 is a fifth current schematic diagram of a twenty-first three-bridge topology device in a battery charging mode according to an embodiment of the present application;

fig. 83 is a sixth schematic current diagram of a twenty-first three-bridge topology device in a battery charging mode according to an embodiment of the present application;

fig. 84 is a current schematic diagram seven illustrating a twenty-first three-arm topology device according to an embodiment of the present application in a battery charging mode;

Fig. 85 is a schematic current diagram eight of a twenty-first three-arm topology device in a battery charging mode according to the embodiment of the present application;

fig. 86 is a schematic diagram illustrating a connection relationship between an LC filter and a second bridge arm and a third bridge arm according to an embodiment of the present disclosure;

fig. 87 is a schematic diagram of a connection relationship between an LCL filter and a second bridge arm and a third bridge arm according to an embodiment of the present disclosure.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without any creative effort belong to the protection scope of the embodiments in the present application.

The battery low-voltage large-current UPS system is one kind of on-line medium and small power UPS system. Namely, no matter whether the grid voltage is normal or not, the alternating voltage used by the load is inverted through the inverter circuit. In terms of power division, an online medium-low power UPS system generally refers to an online UPS system with power between 1 kw and 3 kw.

Fig. 1 is a schematic structural diagram of a battery low-voltage high-current UPS system provided in the prior art. As shown in fig. 1, a conventional battery low-voltage high-current UPS system includes: the power supply comprises a charger, a battery pack, a unidirectional Direct Current (DCDC) converter, a commercial power Alternating Current (AC), a Vienna rectifier converter and a half-bridge inverter.

In the external power supply mode (in the battery low-voltage large-current UPS system, the external power supply is the AC mains supply AC, and therefore, in this example, when the external power supply mode is AC power supply), the vienna rectifier converter converts the AC power provided by the AC mains supply into dc power, the half-bridge inverter converts the dc power into AC power and provides the AC power to the load, and the charger charges the battery pack. In the external power supply mode, the vienna rectifier converter, the half-bridge inverter and the charger are involved in operation, and in this mode, the DCDC converter is in an idle state.

In a battery power supply mode (i.e., when the battery pack supplies power), the DCDC converter boosts the dc power output by the battery pack, and the half-bridge inverter converts the dc power into ac power and supplies the ac power to the load. Namely, the DCDC converter and the half-bridge inverter participate in operation. In the battery-powered mode, the vienna rectifier converter and the charger are idle.

That is to say, when the existing battery low-voltage large-current UPS system works, part of devices are in an idle state, so that the device reuse rate of the existing battery low-voltage large-current UPS system is low, and the cost of the battery low-voltage large-current UPS system is high.

Fig. 1A is a schematic structural diagram of a battery low-voltage large-current inverter system provided in the prior art. As shown in fig. 1A, a battery low-voltage large-current inverter system commonly used in the prior art includes: the system comprises a battery pack, a bidirectional DCDC converter, a Buck converter and a full-bridge inverter. That is, the conventional battery low-voltage large-current inverter system (i.e., bidirectional DCAC converter) is composed of a three-stage converter. The Buck converter may also be referred to as a Buck converter, and is used for performing a voltage reduction process on a voltage.

In the battery power supply mode, the direct current output by the battery pack is boosted to the bus capacitor E1 through the bidirectional DCDC converter, and then is inverted by the full-bridge inverter to output alternating current to a load. In a battery charging mode, the full-bridge inverter serves as a full-bridge rectification PFC converter, alternating current provided by a commercial power alternating current power supply AC is boosted and then output to a bus capacitor E1, and direct current output by the bus capacitor E1 is subjected to voltage reduction through a Buck converter and then charges a battery pack through a bidirectional DCDC converter.

According to the description, the Buck converter does not work in the battery power supply mode of the existing battery low-voltage large-current inverter system, so that the integration level of the existing battery low-voltage large-current inverter system is not high, the reuse rate of devices is not high, and the cost of the battery low-voltage large-current inverter system is high.

In summary, the device reuse rate of the existing power supply system with low voltage and large current of the battery is low, which results in high cost of the power supply system with low voltage and large current of the battery.

In view of the above problems, the embodiments of the present application provide a three-bridge topology apparatus, when the apparatus is applied to a battery low-voltage large-current UPS system or an inverter system, no matter the apparatus charges or discharges a battery pack, all devices of the apparatus all participate in operation, thereby increasing the device reuse rate of the battery low-voltage large-current UPS system or the inverter system, and further reducing the cost of the battery low-voltage large-current UPS or the inverter system.

It should be understood that the embodiment of the present application does not limit the external power supply of the battery low-voltage high-current UPS system. For example, the external power supply of the UPS system may be a commercial AC power supply AC, a photovoltaic PV dc power supply, or a photovoltaic PV dc power supply + a commercial AC power supply AC. For convenience of description, the following embodiments are all described by taking a commercial AC power source AC as an external power source of a battery low-voltage large-current UPS system as an example. However, it can be understood by those skilled in the art that the commercial power AC power source related in the subsequent figures may be replaced by other independent external power sources, and for a UPS system having two external power sources at the same time, the circuit connection mode may be adaptively adjusted according to the actual connection mode of the external power sources in the UPS system, which is not described again.

The three-bridge-arm topology device provided by the embodiment of the application can comprise the following structures:

structure a: the three-bridge arm topology device comprises: the device comprises a battery pack, a voltage conversion circuit, a change-over switch and a three-bridge arm circuit. The change-over switch controls the voltage conversion circuit to charge or discharge the battery pack, so that all devices of the three-bridge arm topology device participate in working no matter whether the battery pack is charged or discharged.

The three-bridge-arm topological device provided by the structure A can be applied to a battery low-voltage large-current UPS system.

Structure B: the three-bridge arm topology device comprises: the battery pack, the voltage conversion circuit and the three-bridge arm circuit are not provided with a change-over switch any more. The voltage conversion circuit can charge or discharge the battery pack, so that all devices of the three-bridge arm topology device can participate in work whether charging or discharging the battery pack.

Optionally, in some embodiments, the voltage conversion circuit of the three-bridge-arm topology device shown in the structure B may multiplex a dc bus capacitor of the three-bridge-arm circuit, or multiplex a second bridge arm of the three-bridge-arm circuit and the dc bus capacitor, so as to implement a voltage conversion function, so as to achieve the purpose of simplifying the voltage conversion circuit, and further improve the device reuse rate of the three-bridge-arm topology device.

The three-bridge arm device of the topology device provided by the structure B can be applied to a battery low-voltage large-current UPS system or a battery low-voltage large-current inverter system.

The three-arm topology device provided by the embodiments of the present application is described in detail below with reference to specific embodiments. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

Structure a: the three-bridge arm topology device comprises: the device comprises a battery pack, a voltage conversion circuit, a change-over switch and a three-bridge arm circuit. The three-arm topology device provided by the structure a can be applied to a battery low-voltage large-current UPS system, for example, a battery low-voltage large-current UPS system with a wide battery pack input voltage range, and an exemplary battery low-voltage large-current UPS system using a lead-acid battery. It should be understood that the battery pack input voltage referred to herein refers to the voltage output by the battery pack when the battery pack is used to power a load. In some embodiments, the three-arm topology may also be applied to Emergency Power Supply (EPS) systems.

Fig. 2 is a first schematic diagram of a first three-arm topology device according to an embodiment of the present application. As shown in fig. 2, the three-arm topology device may include: the device comprises a battery pack, a voltage conversion circuit, a change-over switch and a three-bridge arm circuit.

The three-arm circuit may include: the bridge type power amplifier comprises a first bridge arm, a second bridge arm, a third bridge arm, a first inductor L1, a direct-current bus capacitor E1 and an LC filter. Wherein the LC filter comprises: a first capacitor Co and a second inductor L2.

The first bridge arm comprises a first switch tube Q1 and a second switch tube Q2, the first switch tube Q1 and the second switch tube Q2 are connected in series between a BUS + and a BUS-, the BUS + is a positive output end of a BUS, and the BUS-is a negative output end of the BUS. For example, a first end of the first switch transistor Q1 is connected to BUS +, a second end of the first switch transistor Q1 is connected to a first end of the second switch transistor Q2, and a second end of the second switch transistor Q2 is connected to BUS-. The common end of the first switch tube Q1 and the second switch tube Q2 is referred to as the midpoint of the first leg. When the three-arm topology device is applied to a battery low-voltage large-current UPS system, the first arm can also be called a Power Factor Correction (PFC) side high-frequency arm.

The second bridge arm comprises a third switching tube Q3 and a fourth switching tube Q4, and the third switching tube Q3 and the fourth switching tube Q4 are connected between BUS + and BUS-in series. For example, a first end of the third switching tube Q3 is connected to BUS +, a second end of the third switching tube Q3 is connected to a first end of the fourth switching tube Q4, and a second end of the fourth switching tube Q4 is connected to BUS-. The common end of the third switching tube Q3 and the fourth switching tube Q4 is referred to as the midpoint of the second leg. When the three-arm topology device is applied to a battery low-voltage high-current UPS system, the second arm may also be referred to as an arm shared by a PFC and an Inverter (INV).

The third bridge arm comprises a fifth switch tube Q5 and a sixth switch tube Q6, and the fifth switch tube Q5 and the sixth switch tube Q6 are connected in series between BUS + and BUS-. For example, a first end of the fifth switching tube Q5 is connected to BUS +, a second end of the fifth switching tube Q5 is connected to a first end of the sixth switching tube Q6, and a second end of the sixth switching tube Q6 is connected to BUS-. The common end of the fifth switching tube Q5 and the sixth switching tube Q6 is referred to as the midpoint of the third leg. When the three-arm topology device is applied to a battery low-voltage high-current UPS system, the third arm may also be referred to as an INV-side high-frequency arm.

A DC BUS capacitor E1 is connected between BUS + and BUS-. That is, first leg, second leg, third leg, and dc BUS capacitor E1 are connected in parallel between BUS + and BUS-.

The first inductor L1 is a high-frequency inductor on the PFC side. The midpoint of the first bridge arm is connected to the first end of the first inductor L1, and the second end of the first inductor L1 serves as the positive voltage input AC _ L of the three-bridge arm topology device. And the middle point of the second bridge arm is used as a negative voltage input end AC _ N of the three-bridge-arm topological device.

The second inductor L2 is a high-frequency inductor on the INV side. The midpoint of the third bridge arm is connected with the first end of a second inductor L2, the second end of a second inductor L2 is connected with the first end of a first capacitor Co, and the second end of the first capacitor Co is connected with the midpoint of the second bridge arm. The first end of the first capacitor Co is a first output end of the three-bridge-arm topology device, and the second end of the first capacitor Co is a second output end of the three-bridge-arm topology device.

The positive pole of the battery pack is connected with the first end of the voltage conversion circuit, and the negative pole of the battery pack is connected with the second end of the voltage conversion circuit. The third end of the voltage conversion circuit is connected with a BUS + and the positive voltage input end AC _ L through a selector switch respectively, the fourth end of the voltage conversion circuit is connected with a BUS-, the live wire of the mains supply AC (namely the first end of the external power supply) is connected with the positive voltage input end AC _ L through the selector switch, and the zero wire of the mains supply AC (namely the second end of the external power supply) is connected with the negative voltage input end AC _ N. The first output end and the second output end of the three-bridge-arm topological device are both connected with the load to provide alternating current for the load.

The battery pack may include at least one battery, and may be determined according to the power of a UPS system to which the three-arm topology apparatus is applied, for example, the UPS system may be an online UPS system with a power between 1 kw and 3 kw, or the UPS may be a battery low-voltage high-current UPS system.

The three-bridge-arm circuit according to this embodiment is used to implement rectification and inversion functions when the three-bridge-arm topology device supplies power to a load, and may be specifically introduced and described with reference to a power supply mode adopted when the following three-bridge-arm topology device supplies power to a load. Therefore, in some embodiments, the three-arm circuit according to the present embodiment may also be referred to as a three-arm conversion circuit.

Specifically, the three-bridge-arm topology device has two power supply modes, which are respectively: an external power mode and a battery power mode. In accordance with the UPS system according to the present embodiment, the external power supply mode may be a mode in which stable commercial power is supplied from a commercial power AC; the battery power supply mode may be a mode in which power is supplied by a battery pack of the UPS system, and at this time, a commercial power input from the commercial AC power source AC is a high voltage, or a low voltage, or a frequency abnormality, or no commercial power input. The three-arm topology can be switched between the two modes by switching the switches.

In the external power supply mode, the change-over switch can control a commercial power alternating current power supply AC to supply power for the three-bridge arm circuit. At this time, the three-arm circuit operates in an AC-AC mode. For example, the PFC of the three-arm circuit converts the AC power input from the AC mains supply into a dc power (i.e., rectifies the AC power input from the AC mains supply), the dc bus capacitor E1 filters (may also be called as voltage stabilization) the dc power converted by the PFC to obtain a stable dc power, and the INV of the three-arm circuit converts the stable dc power into an AC power and outputs the AC power to the load to supply power to the load.

Although the PFC converts ac power into dc power, the dc power still contains a certain pulsating ac component, which is referred to as a ripple voltage. Therefore, in the external power supply mode, the dc bus capacitor E1 may filter (may also be called as a voltage stabilizing) the dc power converted by the PFC to filter the ripple voltage in the dc power, so as to obtain a smooth and stable dc voltage. Meanwhile, the direct current bus capacitor E1 can store energy.

In the external power supply mode, the switch can control the voltage conversion circuit to charge the battery pack. For example, the switch can control the voltage conversion circuit to charge the battery pack when the external power supply mode is in the low voltage state of the battery pack. Namely, the charging of the battery pack is realized by multiplexing the voltage conversion circuit, and no additional charger is needed. At this time, in the external power supply mode, both the voltage conversion circuit and the three-bridge arm circuit participate in operation, that is, all devices of the three-bridge arm topology device participate in operation.

For example, the change-over switch may control the voltage conversion circuit to be hung between the BUS + and the BUS-, the voltage conversion circuit operates in a BUCK mode (i.e., a step-down mode), and performs step-down processing on a BUS voltage (i.e., a voltage obtained by filtering direct current obtained by converting PFC by the direct current BUS capacitor E1) output by the direct current BUS capacitor E1 to obtain a charging voltage of the battery pack, so as to charge the battery pack with the charging voltage. At this time, the battery pack serves as an output source of the voltage conversion circuit.

Referring to fig. 1, when a battery pack is charged by a charger in the prior art, the charger needs to be provided with: the alternating current rectifier circuit is used for rectifying alternating current provided by a commercial alternating current power supply to obtain direct current. The voltage reduction circuit is used for carrying out voltage reduction treatment on the direct current to obtain the charging voltage of the battery pack. Such a charger provided with a rectifying circuit and a voltage step-down circuit is generally called a flyback charger.

Because the alternating current that commercial power alternating current power supply provided has the undulant condition of wide voltage range, consequently, the step-down circuit that sets up in the charger needs to realize the wide range voltage regulation, leads to step-down circuit's voltage conversion efficiency lower, consequently, when adopting this type of flyback charger to charge for the group battery, the charging efficiency of charger is lower.

In the embodiment of the present application, the BUS voltage output by the dc BUS capacitor E1 is a stable dc voltage obtained by PFC rectification of the three-arm circuit, so that when the BUS voltage output by the dc BUS capacitor E1 is used to charge the battery pack, the voltage conversion circuit can be reused to perform voltage reduction processing on the BUS voltage output by the dc BUS capacitor E1, and a rectification circuit does not need to be separately provided. Or, the PFC of the three-arm circuit is multiplexed, and the direct current for charging the battery pack is obtained.

In addition, because the BUS voltage output by the direct current BUS capacitor E1 is stable direct current, the BUS voltage output by the direct current BUS capacitor E1 can be subjected to voltage reduction processing without using a voltage conversion circuit with wide voltage regulation range, the conversion efficiency of the voltage conversion circuit is improved, and the charging efficiency of the battery pack is further improved.

In the battery power supply mode, the switch can control the voltage conversion circuit to discharge the battery pack. Illustratively, the switch may control the voltage conversion circuit to switch on between the high frequency inductor (i.e., the first inductor L1) on the PFC side and the BUS-. At this time, the voltage conversion circuit and the Boost circuit formed by the first inductor L1 and the first arm of the three-arm circuit are connected in series, and two-stage Boost processing is realized when the battery pack is discharged. Specifically, the voltage conversion circuit operates in a Boost mode (i.e., a Boost mode) to perform primary Boost processing on the output voltage of the battery pack, the first inductor L1 and the first bridge arm of the three-bridge arm circuit form the Boost circuit to perform secondary Boost processing on the output voltage of the battery pack, and the boosted voltage is input to the dc bus capacitor E1 of the three-bridge arm circuit to maintain bus voltage balance.

In a UPS system with low battery voltage and high current, the battery pack outputs a lower voltage, and the load requires a higher voltage. Therefore, when the three-arm topology device is applied to a UPS system with low-voltage and high-current batteries, the three-arm topology device needs to boost a lower voltage to a higher voltage, that is, needs to perform a boosting process with a larger voltage difference when the UPS system with low-voltage and high-current batteries uses a battery pack to supply power to a load. If the voltage conversion circuit is connected in parallel with the "first inductor L1 and the Boost circuit formed by the first arm of the three-arm circuit" to perform the boosting operation using only the voltage conversion circuit (i.e., to perform the first-stage boosting process using the voltage conversion circuit), there are the following problems:

1. the voltage conversion circuit has a limitation of a maximum voltage boosting ratio (for example, the output voltage is divided by the input voltage), which may cause the voltage conversion circuit to use the voltage boosted by the maximum voltage boosting ratio, which is still smaller than the voltage required by the load of the UPS system with low voltage and large current of the battery, and thus cannot meet the use requirement of the UPS system with low voltage and large current of the battery.

2. The higher the step-up ratio, the lower the conversion efficiency of the voltage conversion circuit, and the greater the risk of current stress and heat loss of the voltage conversion circuit. Therefore, the above-mentioned first-stage boosting process using the voltage conversion circuit requires the voltage conversion circuit to perform a boosting process with a high boosting ratio, which results in low conversion efficiency of the voltage conversion circuit and high risk of current stress and heat loss of the voltage conversion circuit.

In view of the above problems in the first-stage boosting process using the voltage conversion circuit, in the embodiment of the present application, the voltage conversion circuit and the "first inductor L1 and the first arm of the three-arm circuit form the Boost voltage circuit" are connected in series to implement two-stage boosting, so that the Boost voltage circuit formed by the first inductor L1 and the first arm of the three-arm circuit shares a part of voltage boosting operations, and the voltage conversion circuit itself does not need to perform the boosting process with a large voltage difference while obtaining a large boosting ratio. When the voltage difference between the input voltage and the output voltage of the voltage conversion circuit is smaller, that is, the boosting ratio is smaller, the voltage conversion efficiency of the voltage conversion circuit is higher. Therefore, the conversion efficiency of the voltage conversion circuit can be improved by the two-stage boosting mode, the current stress risk and the heat loss risk of the voltage conversion circuit are further reduced, and the reliability of the UPS system with the low-voltage and large-current battery is improved.

In the battery power supply mode, the battery pack is an input source of the voltage conversion circuit, and the output of the voltage conversion circuit supplies power for the three-bridge arm circuit. At this time, the first leg of the three-leg circuit operates in the DC-DC mode. For example, a first bridge arm and a first inductor L1 of the three-bridge-arm circuit work in a Boost mode, a direct-current bus capacitor E1 filters boosted direct current to obtain stable direct current, and a second bridge arm and a third bridge arm work in an inverter mode, convert the stable direct current into alternating current and output the alternating current to a load to supply power to the load. Meanwhile, the direct current bus capacitor E1 can store energy. At this time, in the battery power supply mode, the voltage conversion circuit and the three-bridge arm circuit both participate in the operation, that is, all devices of the three-bridge arm topology device participate in the operation.

It is understood that the voltage conversion circuit according to the embodiments of the present application may be any circuit having a bidirectional voltage conversion function. Such as a voltage conversion circuit with soft switching, a voltage conversion circuit with hard switching, etc. The voltage conversion circuit may be a voltage conversion circuit with electrical isolation or a voltage conversion circuit without electrical isolation. Illustratively, the voltage conversion circuit may also be referred to as a DCDC converter.

Fig. 3 is a second schematic diagram of a first three-bridge-arm topology device provided in the embodiment of the present application, and as shown in fig. 3, for example, a voltage conversion circuit according to the embodiment of the present application may include: the transformer comprises a first voltage conversion unit, a second voltage conversion unit, a transformer TX1 and an LC resonant cavity;

the first voltage conversion unit is connected with the low-voltage side of the transformer, and the high-voltage side of the transformer is connected with the resonant cavity and the second voltage conversion unit. The LC resonant cavity includes: a fifth inductor Lik and a third capacitor Cr. It should be understood that the fifth inductor Lik may be an inductor independent from the transformer TX1, or may be a leakage inductor in the transformer TX 1. That is to say, the fifth inductor Lik and the transformer TX1 may be independent devices, or may be a component belonging to the transformer TX1, which is not limited in this embodiment of the application.

The first voltage conversion unit may include: the second voltage conversion unit may include: a sixth bridge arm, a seventh bridge arm and a second capacitor E2.

The fourth bridge arm comprises a seventh switching tube Q7 and an eighth switching tube Q8 which are connected in series, and a first end of the seventh switching tube Q7 is connected with a first end of the eighth switching tube Q8. At this time, a common end of the seventh switching tube Q7 and the eighth switching tube Q8 is referred to as a midpoint of the fourth arm.

The fifth bridge arm comprises a ninth switching tube Q9 and a tenth switching tube Q10 which are connected in series, and a first end of the ninth switching tube Q9 is connected with a first end of the tenth switching tube Q10. At this time, a common end of the ninth switching tube Q9 and the tenth switching tube Q10 is referred to as a midpoint of the fifth arm.

The sixth bridge arm comprises an eleventh switching tube Q11 and a twelfth switching tube Q12 which are connected in series, and a first end of the eleventh switching tube Q11 is connected with a first end of the twelfth switching tube Q12. At this time, a common end of the eleventh switching tube Q11 and the twelfth switching tube Q12 is referred to as a midpoint of the sixth arm.

The seventh bridge arm includes a thirteenth switching tube Q13 and a fourteenth switching tube Q14 connected in series, and a first end of the thirteenth switching tube Q13 is connected to a first end of the fourteenth switching tube Q14. At this time, the common end of the thirteenth switching tube Q13 and the fourteenth switching tube Q14 is referred to as the midpoint of the seventh arm.

And the fourth bridge arm is connected with the fifth bridge arm in parallel. For example, the second terminal of the seventh switching tube Q7 is connected to the second terminal of the ninth switching tube Q9, and the second terminal of the eighth switching tube Q8 is connected to the second terminal of the tenth switching tube Q10.

The sixth bridge arm, the seventh bridge arm, and the second capacitor E2 are connected in parallel. For example, the second terminal of the eleventh switch tube Q11 is connected to the second terminal of the thirteenth switch tube Q13 and the first terminal of the second capacitor E2, and the second terminal of the twelfth switch tube Q12 is connected to the second terminal of the fourteenth switch tube Q14 and the second terminal of the second capacitor E2. It should be understood that the second capacitor E2 may be a dc capacitor for providing a filtering function to provide stable dc power when the voltage converting circuit charges or discharges the battery pack.

A first end a of the transformer TX1 (i.e., a synonym end of a low-voltage side of the transformer TX 1) is connected to a midpoint of the fourth bridge arm, a second end B of the transformer TX1 (i.e., a synonym end of a low-voltage side of the transformer TX 1) is connected to a midpoint of the fifth bridge arm, a third end C of the transformer TX1 (i.e., a synonym end of a high-voltage side of the transformer TX 1) is connected to a first end of the fifth inductor Lik, a second end of the fifth inductor Lik is connected to a midpoint of the sixth bridge arm, a fourth end D of the transformer TX1 (i.e., a synonym end of a high-voltage side of the transformer TX 1) is connected to a first end of the third capacitor Cr, and a second end of the third capacitor Cr is connected to a midpoint of the seventh bridge arm.

In the voltage converting circuit, the second terminal of the seventh switching tube Q7 is the first terminal of the voltage converting circuit, the second terminal of the eighth switching tube Q8 is the second terminal of the voltage converting circuit, the second terminal of the thirteenth switching tube Q13 is the third terminal of the voltage converting circuit, and the second terminal of the fourteenth switching tube Q14 is the fourth terminal of the voltage converting circuit.

When the voltage conversion circuit shown in fig. 3 is used to charge the battery pack, the voltage conversion circuit operates in a full-bridge LLC resonant converter mode. That is, the second voltage conversion unit of the voltage conversion circuit, the LC tank, and an inductor (not shown in the figure) in the transformer TX1 form a full-bridge LLC resonant network, so that the voltage conversion circuit forms a full-bridge LLC resonant converter. At this time, the full-bridge LLC resonant converter may be controlled by a full-bridge phase-shift control strategy, so that the leading arm in the full-bridge LLC resonant converter realizes zero-voltage switching-on, and the lagging arm in the full-bridge LLC resonant converter realizes zero-voltage switching-on and zero-current switching-off.

In this full-bridge LLC resonant converter mode, Q11, Q12, Q13, and Q14 function as switching tubes, and external diodes (also referred to as parasitic diodes, etc.) of Q7, Q8, Q9, and Q10 function as rectifiers. For example, the switching tube in the second voltage conversion unit may be controlled to be turned on or off in a manner of shifting the phase and changing the duty ratio to charge the battery pack. The phase-shifting duty ratio is to change the conduction time of the switching tube in the second voltage conversion unit by adjusting the phase difference between the leading arm and the lagging arm in the full-bridge LLC resonant converter. The term "constant frequency" as used herein refers to a constant frequency used for voltage regulation control.

When the voltage conversion circuit shown in fig. 3 is used to discharge the battery pack, the voltage conversion circuit works in a full-bridge secondary-side LC resonant converter mode, that is, the first voltage conversion unit of the voltage conversion circuit, the secondary side of the transformer TX1 and the LC resonant cavity form a full-bridge secondary-side LC resonant converter, so as to implement zero-voltage turn-on and zero-current turn-off.

It should be understood that when the voltage conversion circuit discharges the battery pack, the secondary side of the transformer TX1 connected to the LC tank is the high-voltage side of the voltage conversion circuit, and when the voltage conversion circuit charges the battery pack, the secondary side of the transformer TX1 connected to the first voltage conversion unit is the low-voltage side of the voltage conversion circuit.

In the full-bridge secondary-side LC resonant converter mode, Q7, Q8, Q9, and Q10 function as switching tubes, and external diodes (also referred to as parasitic diodes or the like) of Q11, Q12, Q13, and Q14 function as rectifiers. For example, the battery pack may be discharged by a constant-frequency and constant-duty control method. Q7 and Q10 are simultaneously conducted, and Q8 and Q9 are simultaneously conducted. The constant duty ratio here means that Q7, Q8, Q9, and Q10 are controlled using the same duty ratio so that the on-periods of Q7 and Q10 are the same as the on-periods of Q8 and Q9. The fixed frequency here means that the fixed frequency is used for voltage regulation control.

By the structure of the voltage conversion circuit, the soft switching of the voltage conversion circuit can be realized. Soft-Switching (Soft-Switching) is a Switching technology relative to Hard-Switching (Hard-Switching). The soft switching technology can lead the switching tube in the voltage conversion circuit to firstly reduce the voltage to zero before the switching tube is switched on, and firstly reduce the current to zero (namely zero voltage switching-on and zero current switching-off) before the switching tube is switched off, so as to eliminate the overlapping of the voltage and the current in the switching process of the switching tube and reduce the change rate of the voltage and the current, thereby greatly reducing and even eliminating the switching loss of the voltage conversion circuit and realizing the high frequency of the voltage conversion circuit.

The voltage regulating capability of the voltage conversion circuit with the soft switch is poor. That is to say, when the voltage conversion circuit realizes voltage regulation with a large voltage difference, the voltage conversion circuit can only realize zero-voltage switching-on and cannot realize zero-current switching-off, so that the voltage conversion circuit cannot realize soft switching under the full working condition of zero-voltage switching-on and zero-current switching-off, that is, the voltage conversion circuit cannot work under the full working condition of zero-voltage switching-on and zero-current switching-off, and further the conversion efficiency of the voltage conversion circuit is lower than that under the full working condition, and the current stress risk and the heat loss risk of the voltage conversion circuit are increased.

Therefore, when the voltage conversion circuit with the soft switch is applied to the three-bridge topology device provided in the embodiment of the present application, the voltage conversion circuit can realize the soft switching function of a fixed step-up ratio (for example, the fixed step-up ratio can realize voltage regulation with a small voltage difference) by connecting the voltage conversion circuit in series with the "Boost step-up circuit composed of the first inductor L1 and the first bridge arm of the three-bridge circuit", and the Boost step-up circuit composed of the first inductor L1 and the first bridge arm of the three-bridge circuit realizes the voltage regulation function, that is, the voltage conversion circuit with the soft switch can obtain a large step-up ratio without executing a step-up process with a large voltage difference. Therefore, the voltage conversion circuit with the soft switch can work under the full working condition of zero-voltage switching-on and zero-current switching-off, the conversion efficiency of the voltage conversion circuit with the soft switch is improved, the current stress risk and the heat loss risk of the voltage conversion circuit with the soft switch are further reduced, and the reliability of the UPS system with the battery low-voltage and large current is improved.

It should be understood that fig. 3 is only an illustration of a voltage converting circuit with soft switching, and in particular, other voltage converting circuits with soft switching may be adopted in the solution of the embodiment of the present application.

In addition, the first voltage conversion unit in the voltage conversion circuit shown in fig. 3 may also be implemented by using other circuit structures, and other connection manners may also be used between the transformer TX1 and the LC resonant cavity and between the transformer TX1 and the second voltage conversion unit, which may specifically refer to descriptions (for example, descriptions in fig. 25 to fig. 35) for these parts in the following embodiments, and the implementation principles thereof are similar and will not be described again.

In addition, although fig. 3 is a schematic diagram illustrating a voltage converting circuit provided with electrical isolation (for example, the transformer in fig. 3 realizes electrical isolation of the voltage converting circuit), it should be understood that the voltage converting circuit according to the embodiment of the present application may be a voltage converting circuit with electrical isolation or a voltage converting circuit without electrical isolation. For example, the voltage conversion circuit has electrical isolation, the first leg of the three-leg circuit has no electrical isolation, or the voltage conversion circuit has no electrical isolation, the first leg of the three-leg circuit has electrical isolation, or the voltage conversion circuit has no electrical isolation, the first leg of the three-leg circuit has no electrical isolation, or the like.

It should be noted that, when the three-leg topology device is switched from the external power supply mode to the battery power supply mode, or when the three-leg topology device is switched from the battery power supply mode to the external power supply mode, because there is a certain time difference in mode switching (for example, there may be a time difference of X seconds from the disconnection of the utility power to the power supply of the battery pack), during the time difference, the three-leg topology device may use the voltage stored in the dc bus capacitor E1 to supply power to the load, so as to provide stable ac power to the load, thereby avoiding the load from powering down.

The three-bridge-arm topology device provided by the embodiment of the application realizes the charging or discharging of the battery pack through the multiplexing voltage conversion circuit, namely, the battery pack can be charged without additionally adding a charger. In addition, the voltage conversion circuit and the three-arm circuit are both involved in operation, i.e., all devices of the three-arm topology device are involved in operation, no matter in the external power supply mode or the battery power supply mode. When the three-bridge-arm topological device is applied to the battery low-voltage large-current UPS system, the device reuse rate of the system can be improved, the device design redundancy is avoided, and the cost of the battery low-voltage large-current UPS system is further reduced.

The following illustrates an implementation of the above-described diverter switch:

with continued reference to fig. 2, in a three-arm topology, the switch may comprise, for example: a first switch K1, a second switch K2 and a balance component.

The third end of the voltage conversion circuit is connected with the fixed end of the first switch K1, the first selection end of the first switch K1 is connected with the first end of the balance component, the second end of the balance component is connected with BUS +, the second selection end of the first switch K1 is connected with the positive voltage input end AC _ L, the first end of the second switch K2 is connected with the live wire of the alternating current power supply AC, the second end of the second switch K2 is connected with the positive voltage input end AC _ L, and the fourth end of the voltage conversion circuit is connected with BUS-.

In the external power supply mode, the fixed end of the first switch K1 is communicated with the first selection end of the first switch K1, and the second switch K2 is closed; in the battery supply mode, the fixed end of the first switch K1 is connected to the second selection end of the first switch K1, and the second switch K2 is turned off. For example, the first switch K1 may be any selection switch capable of being turned on or off according to a control signal, such as a double-throw relay or a bidirectional electronic switch or a thyristor. The second switch K2 can be any switch capable of being turned on or off according to a control signal, such as a single throw relay, a unidirectional electronic switch, a thyristor, etc.

The balance component is used for balancing the voltage between the BUS of the three-bridge-arm circuit and the voltage conversion circuit in the external power supply mode, so that the phenomenon that the fixed end of the first switch K1 is communicated with the first selection end of the first switch K1 instantly, large current is input into the voltage conversion circuit, and overcurrent protection can be achieved on the voltage conversion circuit.

With continued reference to fig. 2, in a first possible implementation, the balancing component may be, for example, a varistor RZ.

Fig. 4 is a schematic diagram of a second three-arm topology device according to an embodiment of the present application. In a second possible implementation, as shown in fig. 4, the balancing component may be, for example, a negative temperature coefficient thermistor RT.

Fig. 5 is a schematic diagram of a third bridge arm topology device provided in an embodiment of the present application. As shown in fig. 5, in a third possible implementation manner, the balancing component may be, for example, a third inductor L3.

Fig. 6 is a schematic diagram of a fourth three-leg topology device according to an embodiment of the present application. As shown in fig. 6, in a fourth possible implementation manner, the balancing component may be, for example, a resistor R1. In this implementation, the switch may further include: and a third switch K3.

With continued reference to FIG. 6, the third terminal of the voltage conversion circuit is coupled to the first terminal of the third switch K3, and the second terminal of the third switch K3 is coupled to BUS +. Fig. 7 is a schematic diagram of a fifth three-arm topology device according to an embodiment of the present application. In a fifth possible connection, as shown in fig. 7, the third switch K3 is connected in parallel with the resistor R1.

Referring to the change-over switch shown in fig. 6 or 7, in the external power supply mode, when the voltage difference between the bus bar and the voltage conversion circuit is less than or equal to the preset threshold, the third switch K3 is closed, so that the voltage conversion circuit charges the battery pack. In the battery powered mode, the third switch K3 is open. The preset threshold may be, for example, less than or equal to 20V, and may be determined according to a usage environment of a UPS system to which the three-arm topology apparatus is applied.

Illustratively, the third switch K3 can be any switch capable of being turned on or off according to a control signal, such as a single-throw relay, a unidirectional electronic switch, a thyristor, and the like.

It is to be understood that the second switch K2 and the third switch K3 may be the same switch or different switches. For example, the second switch K2 is a thyristor, and the third switch K3 is a unidirectional electronic switch.

The following takes the structure of the three-arm topology device shown in fig. 6 as an example, and schematically illustrates the states of the switches, the states of the switching tubes, and the current directions of the three-arm topology device in different power supply modes:

an external power supply mode: and controlling the fixed end of the first switch K1 to be communicated with the first selection end of the first switch K1, closing the second switch K2, and controlling the third switch K3 to be closed when the voltage difference value between the BUS + of the three-bridge arm topology device and the voltage conversion circuit of the three-bridge arm topology device is smaller than or equal to a preset threshold value. At this time, the voltage conversion circuit operates in Buck mode. The preset threshold may be, for example, less than or equal to 20V, and may be determined according to a usage environment of a UPS system to which the three-arm topology apparatus is applied.

Fig. 8 is a first current schematic diagram of a fourth three-leg topology device provided in the embodiment of the present application in an external power supply mode. As shown in fig. 8, in the first phase of the positive half cycle of the alternating current, the second switching tube Q2 and the fourth switching tube Q4 of the three-leg circuit are controlled to be conducted. At this time, the current in the three-arm topology device flows as follows:

1. the live wire of the commercial power alternating-current power supply AC → the first inductor L1 → the second switching tube Q2 → the fourth switching tube Q4 → the zero wire of the commercial power alternating-current power supply AC constitutes a tank circuit of the first inductor L1.

2. BUS + → the positive pole of voltage conversion circuit → the positive pole of the battery pack → the negative pole of the voltage conversion circuit → BUS-, and an energy storage circuit of the battery pack is formed.

Fig. 9 is a current schematic diagram two of a fourth three-leg topology device provided in the embodiment of the present application in an external power supply mode, and as shown in fig. 9, in a second phase of a positive half-cycle of an alternating current, the first switching tube Q1 and the fourth switching tube Q4 are controlled to be conductive. At this time, the current in the three-arm topology device flows as follows:

1. the live wire of the commercial power alternating-current power supply AC → the first inductor L1 → the first switching tube Q1 → the dc bus capacitor E1 → the fourth switching tube Q4 → the zero line of the commercial power alternating-current power supply AC, and an energy storage loop is formed in which the first inductor L1 and the commercial power simultaneously store energy for the dc bus capacitor E1.

Fig. 10 is a current schematic diagram three of a fourth three-leg topology device provided in the embodiment of the present application in an external power supply mode, and as shown in fig. 10, in a first phase of a negative half-cycle of an alternating current, the first switching tube Q1 and the third switching tube Q3 are controlled to be conductive. At this time, the current in the three-arm topology device flows as follows:

1. The neutral line of the commercial power alternating-current power supply AC → the third switching tube Q3 → the first switching tube Q1 → the first inductor L1 → the live wire of the commercial power alternating-current power supply AC constitute an energy storage loop of the first inductor L1.

Fig. 11 is a current schematic diagram of a fourth three-leg topology device provided in the embodiment of the present application in an external power supply mode, as shown in fig. 11, in a second phase of a negative half cycle of the alternating current, the second switching tube Q2 and the third switching tube Q3 are controlled to be conductive. At this time, the current in the three-arm topology device flows as follows:

1. the zero line of the commercial power alternating-current power supply AC → the third switching tube Q3 → the direct-current bus capacitor E1 → the second switching tube Q2 → the first inductor L1 → the live wire of the commercial power alternating-current power supply AC, and an energy storage loop is formed, wherein the first inductor L1 and the commercial power simultaneously store energy for the direct-current bus capacitor E1.

2. BUS + → the positive pole of the voltage conversion circuit → the positive pole of the battery pack → the negative pole of the voltage conversion circuit → BUS-, constituting the energy storage circuit of the battery pack.

Battery-powered mode: the fixed end of the first switch K1 is controlled to be in communication with the second selection end of the first switch K1, and the second switch K2 and the third switch K3 are controlled to be off. At this time, the voltage conversion circuit operates in a Boost mode.

Fig. 12 is a current schematic diagram five of a fourth three-leg topology device provided in the embodiment of the present application in a battery power supply mode, as shown in fig. 12, in a first stage of the battery power supply mode, the second switching tube Q2 is controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

the positive electrode of the battery pack → the positive electrode of the voltage conversion circuit → the first inductor L1 → the second switching tube Q2 → the negative electrode of the voltage conversion circuit → the negative electrode of the battery pack, which forms a tank circuit of the first inductor L1.

Fig. 12 is a current schematic diagram six of a fourth three-leg topology device provided in the embodiment of the present application in a battery-powered mode, and as shown in fig. 13, in a second stage of the battery-powered mode, the first switching tube Q1 is controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

the positive electrode of the battery pack → the positive electrode of the voltage conversion circuit → the first inductor L1 → the first switching tube Q1 → the direct current bus capacitor E1 → the negative electrode of the voltage conversion circuit → the negative electrode of the battery pack, and the energy storage loop of the direct current bus capacitor E1 is formed.

It should be understood that, although the current flow of the three-leg topology devices shown in fig. 8 to 12 are schematically illustrated by taking the fourth three-leg topology device shown in fig. 6 as an example. However, it can be understood by those skilled in the art that the current direction, and the states of the switches and the switch tubes are also applicable to the three-arm topology device shown in fig. 7, and the implementation principle is similar, and will not be described again.

In addition, when the three-arm topology device with any structure of fig. 2 to 5 is adopted, the states of the switches, the states of the switching tubes, and the current directions of the three-arm topology device in different modes are as follows:

external power supply mode: the fixed end of the first switch K1 is controlled to communicate with the first selection end of the first switch K1, and the second switch K2 is closed. At this time, the voltage conversion circuit operates in Buck mode.

In this mode, the state of each switching tube in the external power supply mode of the three-arm topology device is the same as that of each switching tube in the external power supply mode of the three-arm topology device shown in fig. 6. The current direction of the three-bridge-arm topology device is the same as that of the three-bridge-arm topology device shown in fig. 6 in the external power supply mode, and specific reference may be made to the descriptions corresponding to fig. 8 to fig. 11, which are not described again.

Battery-powered mode: the fixed end of the first switch K1 is controlled to be connected with the second selection end of the first switch K1, and the second switch K2 is controlled to be disconnected. At this time, the voltage conversion circuit operates in a Boost mode.

In this mode, the state of each switching tube of the three-arm topology device in the battery power supply mode is the same as that of each switching tube of the three-arm topology device in the battery power supply mode shown in fig. 6. The current direction of the three-arm topology device is the same as that of the three-arm topology device shown in fig. 6 in the battery power supply mode, and specifically, the description corresponding to fig. 12 to fig. 13 may be referred to, and details thereof are not repeated.

Fig. 14 is a schematic diagram of a sixth three-arm topology device according to an embodiment of the present application. As shown in fig. 4, in the three-arm topology device, the switch may include, for example: a first switch K1, a second switch K2 and a balance component.

The third end of the voltage conversion circuit is respectively connected with the first end of the first switch K1, and the first selection end of the second switch K2 is connected, the second end of the first switch K1 is connected with the first end of the balance element, the second end of the balance element is connected with BUS +, the second selection end of the second switch K2 is connected with the live wire of the mains supply alternating current power supply, the fixed end of the second switch K2 is connected with the positive voltage input end AC _ L, and the fourth end of the voltage conversion circuit is connected with BUS-.

In the external power supply mode, the first switch K1 is closed, and the fixed end of the second switch K2 is communicated with the second selection end of the second switch K2; in the battery power mode, the first switch K1 is turned off, and the fixed terminal of the second switch K2 is communicated with the first selection terminal of the second switch K2. For example, the first switch K1 can be any switch capable of being turned on or off according to a control signal, such as a single throw relay, a unidirectional electronic switch, a thyristor, and the like. The second switch K2 can be any selective switch capable of being turned on or off according to a control signal, such as a double-throw relay or a bidirectional electronic switch or a thyristor.

The balance component is used for balancing voltage between a BUS + of the three-bridge-arm circuit and the voltage conversion circuit in an external power supply mode, so that the phenomenon that large current is input into the voltage conversion circuit when the fixed end of the first switch K1 is communicated with the first selection end of the first switch K1 is avoided, and overcurrent protection can be achieved on the voltage conversion circuit.

With continued reference to fig. 14, in a sixth possible implementation manner, the balancing component may be, for example, a varistor RZ.

Fig. 15 is a schematic diagram of a seventh three-arm topology device according to an embodiment of the present application. In a seventh possible implementation manner, as shown in fig. 15, the balance component may be, for example, a negative temperature coefficient thermistor RT or the like.

Fig. 16 is a schematic diagram of an eighth three-leg topology device according to an embodiment of the present application. As shown in fig. 16, in an eighth possible implementation manner, the balancing component may be, for example, a third inductor L3.

When the three-arm topology device with any one of the structures in fig. 14 to 16 is adopted, the states of the switches, the states of the switching tubes, and the current trends in different modes of the three-arm topology device are as follows:

an external power supply mode: the first switch K1 is controlled to be closed, and the fixed end of the second switch K2 is communicated with the second selection end of the second switch K2. At this time, the voltage conversion circuit operates in Buck mode.

In this mode, the state of each switching tube in the external power supply mode of the three-arm topology device is the same as that of each switching tube in the external power supply mode of the three-arm topology device shown in fig. 6. The current direction of the three-arm topology device is the same as the current direction of the three-arm topology device shown in fig. 6 in the external power supply mode, and specifically, the description corresponding to fig. 8 to fig. 11 may be referred to, and details thereof are not repeated.

Battery-powered mode: the first switch K1 is controlled to be turned off, and the fixed end of the second switch K2 is communicated with the first selection end of the second switch K2. At this time, the voltage conversion circuit operates in a Boost mode.

In this mode, the state of each switching tube of the three-arm topology device in the battery power supply mode is the same as that of each switching tube of the three-arm topology device in the battery power supply mode shown in fig. 6. The current direction of the three-bridge-arm topology device is the same as that of the three-bridge-arm topology device shown in fig. 6 in the battery power supply mode, and specific reference may be made to the descriptions corresponding to fig. 12 to fig. 13, which are not described again.

Fig. 17 is a schematic diagram of a ninth three-arm topology device according to an embodiment of the present application. As shown in fig. 17, in a ninth possible implementation manner, the balancing component may be, for example, a resistor R1. In this implementation, the switch may further include: and a third switch K3.

With continued reference to FIG. 17, the third terminal of the voltage conversion circuit is coupled to the first terminal of the third switch K3, and the second terminal of the third switch K3 is coupled to BUS +. Fig. 18 is a schematic diagram of a tenth three-bridge-arm topology device according to an embodiment of the present application. In a tenth possible connection, as shown in fig. 18, the third switch K3 is connected in parallel with the resistor R1.

Referring to the change-over switch shown in fig. 17 or 18, in the external power supply mode, when the voltage difference between the bus bar and the voltage conversion circuit is less than or equal to the preset threshold, the third switch K3 is closed, so that the voltage conversion circuit charges the battery pack. In the battery powered mode, the third switch K3 is open. The preset threshold may be, for example, less than or equal to 20V, and may be determined according to a usage environment of a UPS system to which the three-arm topology apparatus is applied.

It should be understood that the first switch K1 and the third switch K3 may be the same switch, or different switches. For example, the first switch K1 is a thyristor, the third switch K3 is a unidirectional electronic switch, and the like.

When the three-arm topology device with any one of the structures in fig. 17 to 18 is adopted, the states of the switches, the states of the switching tubes, and the current of the three-arm topology device in different modes are as follows:

external power supply mode: and controlling the first switch K1 to be closed, communicating the fixed end of the second switch K2 with the second selection end of the second switch K2, and controlling the third switch K3 to be closed when the voltage difference value between the BUS of the three-bridge-arm topological device and the voltage conversion circuit of the three-bridge-arm topological device is smaller than or equal to a preset threshold value. At this time, the voltage conversion circuit operates in the Buck mode. The preset threshold may be, for example, less than or equal to 20V, and may be determined according to a usage environment of a UPS system to which the three-arm topology apparatus is applied.

Battery-powered mode: the first switch K1 and the third switch K3 are controlled to be turned off, and the fixed end of the second switch K2 is communicated with the first selection end of the second switch K2. At this time, the voltage conversion circuit operates in a Boost mode.

Fig. 19 is a schematic diagram of an eleventh three-arm topology device according to an embodiment of the present application. As shown in fig. 19, in the three-arm topology device, the switch may include, for example: the circuit comprises a first switch K1, a second switch K2, a third switch K3 and a balance component.

The third end of the voltage conversion circuit is connected with the first end of the first switch K1 and the first end of the third switch K3 respectively, the second end of the first switch K1 is connected with the positive voltage input end AC _ L, the first end of the second switch K2 is connected with the live wire of the mains supply AC, the second end of the second switch K2 is connected with the positive voltage input end AC _ L, the second end of the third switch K3 is connected with the first end of the balance component, the second end of the balance component is connected with the BUS +, and the fourth end of the voltage conversion circuit is connected with the BUS-.

In the external power supply mode, the first switch K1 is open, and the second switch K2 and the third switch K3 are closed; in the battery powered mode, the first switch K1 is closed and the second switch K2 and the third switch K3 are open.

The balance component is used for balancing the voltage between the BUS of the three-bridge-arm circuit and the voltage conversion circuit in the external power supply mode, so that the phenomenon that the first switch K3 is closed instantly, large current is input into the voltage conversion circuit, and overcurrent protection can be achieved for the voltage conversion circuit.

With continued reference to fig. 19, in an eleventh possible implementation, the balancing component may be, for example, a varistor RZ.

Fig. 20 is a schematic diagram of a twelfth three-bridge-arm topology device according to an embodiment of the present application. As shown in fig. 20, in a twelfth possible implementation manner, the balancing component may be, for example, a negative temperature coefficient thermistor RT.

Fig. 21 is a schematic diagram of a thirteenth three-leg topology device according to an embodiment of the present application. As shown in fig. 21, in a thirteenth possible implementation manner, the balancing component may be, for example, a third inductor L3.

When the three-arm topology device with any one of the structures in fig. 19 to fig. 21 is adopted, the states of the switches, the states of the switching tubes, and the current trends in different modes are as follows:

External power supply mode: the first switch K1 is controlled to be open, and the second switch K2 and the third switch K3 are controlled to be closed. At this time, the voltage conversion circuit operates in the Buck mode.

Battery-powered mode: the first switch K1 is controlled to be closed, and the second switch K2 and the third switch K3 are controlled to be open. At this time, the voltage conversion circuit operates in a Boost mode.

Fig. 22 is a schematic diagram of a fourteenth three-leg topology device according to an embodiment of the present application. As shown in fig. 22, in a fourteenth possible implementation manner, the balancing component may be, for example, a resistor R1. In this implementation, the switch may further include: a fourth switch K4.

With continued reference to FIG. 22, the third terminal of the voltage conversion circuit is coupled to a first terminal of a fourth switch K4, and a second terminal of the fourth switch is coupled to BUS +. Fig. 23 is a schematic diagram of a fifteenth three-bridge-arm topology device according to an embodiment of the present application. In a fifteenth possible connection, as shown in fig. 23, a fourth switch K4 is connected in parallel with a resistor R1.

Referring to the change-over switch shown in fig. 22 or 23, in the external power supply mode, when the voltage difference between the bus bar and the voltage conversion circuit is less than or equal to the preset threshold, the fourth switch K4 is closed, so that the voltage conversion circuit charges the battery pack. In the battery powered mode, the fourth switch K4 is open. The preset threshold may be, for example, less than or equal to 20V, and may be determined according to a usage environment of a UPS system to which the three-arm topology apparatus is applied.

Illustratively, the fourth switch K4 may be any switch capable of being turned on or off according to a control signal, such as a single-throw relay, a unidirectional electronic switch, a thyristor, and the like.

In the present embodiment, the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 may be any switches capable of being turned on or off according to a control signal, for example, a single-throw relay, a unidirectional electronic switch, a thyristor, etc. It should be understood that the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 may use the same switch, or may use different switches. For example, the first switch K1 is a thyristor, the second switch K2, the third switch K3 and the fourth switch K4 are single throw relays, and the like, which is not limited in this embodiment.

When the three-arm topology device having any one of the structures in fig. 22 to 23 is adopted, the states of the switches, the states of the switching tubes, and the current in different modes of the three-arm topology device are as follows:

external power supply mode: and controlling the first switch K1 to be opened, the second switch K2 and the third switch K3 to be closed, and controlling the fourth switch K4 to be closed when the voltage difference value between the BUS of the three-arm topology device and the voltage conversion circuit of the three-arm topology device is smaller than or equal to a preset threshold value. At this time, the voltage conversion circuit operates in Buck mode. The preset threshold may be, for example, less than or equal to 20V, and may be specifically determined according to a usage environment of a UPS system to which the three-arm topology apparatus is applied.

Battery-powered mode: the first switch K1 is controlled to be closed and the second switch K2, the third switch K3 and the fourth switch K4 are controlled to be open. At this time, the voltage conversion circuit operates in a Boost mode.

In this mode, the states of the switching tubes of the three-arm topology device in the battery power supply mode are the same as the states of the switching tubes of the three-arm topology device shown in fig. 6 in the battery power supply mode. The current direction of the three-bridge-arm topology device is the same as that of the three-bridge-arm topology device shown in fig. 6 in the battery power supply mode, and specific reference may be made to the descriptions corresponding to fig. 12 to fig. 13, which are not described again.

It should be understood that the switches shown in fig. 2, fig. 4 to fig. 7, and fig. 14 to fig. 23 are only examples, and since the implementation of the switches is numerous, the switches applied to the three-leg topology device are not listed here. During concrete implementation, a change-over switch can be selected according to actual requirements, so that the voltage conversion circuit is controlled to charge the battery pack in an external power supply mode, and the voltage conversion circuit is controlled to discharge the battery pack in a battery power supply mode, and the details are not repeated.

In the examples of the three-bridge arm topology devices shown in fig. 2, 4 to 7, and 14 to 23, the voltage conversion circuit may be any circuit having a bidirectional voltage conversion function. For example, the voltage conversion circuit shown in fig. 3, etc., but this is not limited thereto.

Structure B: the three-bridge arm topology device comprises: the system comprises a battery pack, a voltage conversion circuit, a three-bridge arm circuit and no change-over switch. The three-bridge-arm topological device can be applied to an inverter system of battery low-voltage large current or a battery low-voltage large current UPS system. It should be noted that, in the following embodiments, the same or similar concepts or processes as those in the foregoing three-arm topology device are referred to, and details are not repeated, and reference may be specifically made to the description of the foregoing three-arm topology device.

Fig. 24 is a schematic diagram of a sixteenth three-bridge-arm topology apparatus according to an embodiment of the present application. As shown in fig. 24, the three-bridge arm topology device may include: the circuit comprises a battery pack, a voltage conversion circuit and a three-bridge arm circuit. The voltage conversion circuit is respectively connected with the battery pack and the three-bridge arm circuit.

The three-bridge arm circuit includes: the bridge circuit comprises a first bridge arm, a second bridge arm, a third bridge arm, a direct current bus capacitor E1 and an LC filter. The first bridge arm comprises a first switching tube and a second switching tube which are connected in series; the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series; the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series; the LC filter includes: a first capacitor Co and a second inductor L2. The first bridge arm, the second bridge arm, the third bridge arm and the direct current BUS capacitor E1 are connected in parallel between a positive BUS output end BUS + and a negative BUS output end BUS-; the midpoint of the third bridge arm is connected with the first end of a second inductor L2, the second end of a second inductor L2 is connected with the first end of a first capacitor Co, and the second end of the first capacitor Co is connected with the midpoint of the second bridge arm. The first end of the first capacitor Co is a first output end of the three-bridge-arm topology device, and the second end of the first capacitor Co is a second output end of the three-bridge-arm topology device.

In this embodiment, the voltage conversion circuit may implement a voltage conversion function through its own circuit structure, or by multiplexing the bus capacitor E1 of the three-arm circuit, or by "multiplexing the second arm and the bus capacitor E1". Therefore, no matter the battery pack is charged or discharged, all the devices of the three-bridge-arm topological device participate in work, and the device reuse rate of the three-bridge-arm topological device is improved. When the three-bridge-arm topological device is applied to a battery low-voltage large-current UPS system or an inverter system, the device reuse rate of the battery low-voltage large-current UPS system or the inverter system can be improved, and the cost of the system is further reduced.

The following explains the specific structure and the working principle of the three-arm topology device, specifically:

structure B1: the voltage conversion circuit in the three-bridge-arm topological device realizes a voltage conversion function through a circuit structure of the voltage conversion circuit. The three-bridge-arm topology device is applied to a battery low-voltage large-current UPS system with a commercial power alternating current power supply AC as an external power supply. For example, a battery pack input voltage narrow range battery voltage high current UPS system, and, for example, a battery voltage high current UPS system using a lithium battery. It should be understood that the battery pack input voltage referred to herein refers to the voltage output by the battery pack when the battery pack is used to power a load. In some embodiments, the three-arm topology may also be applied to Emergency Power Supply (EPS) systems.

With continued reference to fig. 24, in this configuration B1, the three-bridge arm circuit of the three-bridge arm topology device further includes a first inductance L1.

The first inductor L1 is a high-frequency inductor on the PFC side, and an inductor (e.g., the second inductor L2) included in the filter is a high-frequency inductor on the INV side. The midpoint of the first bridge arm is connected to the first end of the first inductor L1, and the second end of the first inductor L1 serves as the positive voltage input AC _ L of the three-bridge arm topology device. And the middle point of the second bridge arm is used as a negative voltage input end AC _ N of the three-bridge-arm topological device. The live wire of the commercial power alternating current power supply AC is connected with the positive voltage input end AC _ L, and the zero line of the commercial power alternating current power supply AC is connected with the negative voltage input end AC _ N.

Optionally, in some embodiments, the live line of the mains AC supply is connected to the positive voltage input AC _ L through a switch K5 to meet the safety requirements of the three-arm topology device. It should be understood that the switch K5 may be, for example, a unidirectional electronic switch, a triac, etc.

The midpoint of the third bridge arm is connected with the first end of a second inductor L2, the second end of a second inductor L2 is connected with the first end of a first capacitor Co, and the second end of the first capacitor Co is connected with the midpoint of the second bridge arm. The first end of the first capacitor Co is a first output end of the three-bridge-arm topological device, and the second end of the first capacitor Co is a second output end of the three-bridge-arm topological device and is connected with the load.

The positive pole of the battery pack is connected with the first end of the voltage conversion circuit, and the negative pole of the battery pack is connected with the second end of the voltage conversion circuit. The third end of the voltage conversion circuit is connected with BUS +, and the fourth end of the voltage conversion circuit is connected with BUS-.

The three-bridge-arm circuit according to this embodiment is configured to implement rectification and inversion functions when the three-bridge-arm topology device supplies power to a load, and may be specifically introduced and described with reference to a power supply mode adopted when the three-bridge-arm topology device supplies power to the load. Therefore, in some embodiments, the three-arm circuit according to the present embodiment may also be referred to as a three-arm conversion circuit.

Specifically, the three-bridge-arm topology device has two power supply modes, which are respectively: an external power mode and a battery power mode.

Under the external power supply mode, a commercial power alternating current power supply AC supplies power for the three-bridge arm circuit, and the voltage conversion circuit charges the battery pack. At this time, the three-arm circuit operates in an AC-AC mode, the voltage conversion circuit operates in a BUCK mode (i.e., a step-down mode), and the BUS voltage output by the dc BUS capacitor E1 is stepped down to obtain a charging voltage of the battery pack, so that the battery pack is charged by using the charging voltage. At this time, the battery pack serves as an output source of the voltage conversion circuit.

In this way, in the external power supply mode, both the voltage conversion circuit and the three-bridge-arm circuit participate in operation, i.e., all devices of the three-bridge-arm topology device participate in operation. Regarding the technical effect of using the voltage conversion circuit to charge the battery pack, reference may be made to the description of using the voltage conversion circuit to charge the battery pack in fig. 2 of the foregoing embodiment.

In the battery power supply mode, the battery pack is an input source of the voltage conversion circuit, and the output of the voltage conversion circuit supplies power for the three-bridge arm circuit. That is, the voltage conversion circuit discharges the battery pack. At this time, the voltage conversion circuit operates in a Boost mode (i.e., a Boost mode), performs a Boost process on the output voltage of the battery pack, and inputs the boosted voltage to the dc bus capacitor E1 of the three-arm circuit to maintain the bus voltage balance. A first bridge arm of the three-bridge-arm circuit works in a DC-DC mode, a direct-current bus capacitor E1 filters boosted direct current to obtain stable direct current, a second bridge arm and a third bridge arm of the three-bridge-arm circuit work in an inversion mode, the stable direct current is converted into alternating current and then output to a load, and power is supplied to the load. Meanwhile, the direct current bus capacitor E1 can store energy. By the mode, in the battery power supply mode, the voltage conversion circuit and the three-bridge-arm circuit are both involved in working, namely all devices of the three-bridge-arm topological device are involved in working.

It can be understood that the voltage conversion circuit according to the embodiment of the present application may be a voltage conversion circuit with electrical isolation, or may be a voltage conversion circuit without electrical isolation. Illustratively, the voltage conversion circuit may also be referred to as a DCDC converter.

Continuing to refer to fig. 24, for example, the voltage conversion circuit according to the embodiment of the present application may include: the device comprises a first voltage conversion unit, a transformer, an LC resonant cavity and a second voltage conversion unit. The first voltage conversion unit is connected with the low-voltage side of the transformer, and the high-voltage side of the transformer is connected with the LC resonant cavity and the second voltage conversion unit.

With continued reference to fig. 24, illustratively, the first voltage converting unit includes: a fourth bridge arm and a fifth bridge arm. The LC resonant cavity includes: a fifth inductor Lik and a third capacitor Cr. The second voltage conversion unit includes: a sixth leg and a seventh leg. That is, the second voltage conversion unit in the present embodiment is a full-bridge topology.

Wherein the fourth leg comprises: a seventh switch tube Q7 and an eighth switch tube Q8 connected in series (i.e., the first end of the seventh switch tube Q7 is connected to the first end of the eighth switch tube Q8); the fifth leg includes: a ninth switching tube Q9 and a tenth switching tube Q10 (i.e. the first end of the ninth switching tube Q9 is connected to the first end of the tenth switching tube Q10) connected in series. The fourth leg is connected in parallel with the fifth leg (i.e., the second end of the seventh switching tube Q7 is connected to the second end of the ninth switching tube Q9, and the second end of the eighth switching tube Q8 is connected to the second end of the tenth switching tube Q10).

The sixth leg includes: an eleventh switch tube Q11 and a twelfth switch tube Q12 connected in series (i.e. a first end of the eleventh switch tube Q11 is connected with a first end of the twelfth switch tube Q12); the seventh bridge arm includes: a thirteenth switching tube Q13 and a fourteenth switching tube Q14 connected in series (i.e., the first end of the thirteenth switching tube Q13 is connected to the first end of the fourteenth switching tube Q14). The seventh bridge arm is connected in parallel with the sixth bridge arm (i.e., the second end of the eleventh switch tube Q11 is connected to the second end of the thirteenth switch tube Q13, and the second end of the twelfth switch tube Q12 is connected to the second end of the fourteenth switch tube Q14).

For the description of the fourth bridge arm, the fifth bridge arm, the sixth bridge arm, the seventh bridge arm and the LC resonant cavity, reference may be made to the description of the fourth bridge arm, the fifth bridge arm, the sixth bridge arm, the seventh bridge arm and the resonant cavity in fig. 3, and details are not repeated here. In some embodiments, the first voltage conversion unit shown in fig. 24 may also be referred to as a full-bridge conversion circuit.

The second terminal of the seventh switching tube Q7 is the first terminal of the voltage converting circuit, the second terminal of the eighth switching tube Q8 is the second terminal of the voltage converting circuit, the second terminal of the thirteenth switching tube Q13 is the third terminal of the voltage converting circuit, and the second terminal of the fourteenth switching tube Q14 is the fourth terminal of the voltage converting circuit.

The middle point of the fourth bridge arm is connected with the different-name end of the low-voltage side of the transformer TX1, and the middle point of the fifth bridge arm is connected with the same-name end of the low-voltage side of the transformer TX 1. The dotted end of the high-voltage side of the transformer is connected with the first end of the fifth inductor Lik, the second end of the fifth inductor Lik is connected with the midpoint of the sixth bridge arm, the dotted end of the high-voltage side of the transformer is connected with the first end of the third capacitor Cr, and the second end of the third capacitor Cr is connected with the midpoint of the seventh bridge arm.

When the voltage conversion circuit is used for charging the battery pack, the voltage conversion circuit works in a full-bridge LLC resonant converter mode. That is, the second voltage conversion unit of the voltage conversion circuit, the LC tank, and an inductor (not shown in the figure) in the transformer TX1 form a full-bridge LLC resonant network, so that the voltage conversion circuit forms a full-bridge LLC resonant converter. At this time, the full-bridge LLC resonant converter may be controlled by a full-bridge phase-shift control strategy, so that the leading arm in the full-bridge LLC resonant converter realizes zero-voltage switching-on, and the lagging arm in the full-bridge LLC resonant converter realizes zero-voltage switching-on and zero-current switching-off.

When the voltage conversion circuit is adopted to discharge the battery pack, the voltage conversion circuit works in a full-bridge secondary side LC resonance converter mode, namely, a first voltage conversion unit of the voltage conversion circuit, a secondary side of a transformer TX1 and an LC resonance cavity form a full-bridge secondary side LC resonance converter, and zero voltage switching-on and zero current switching-off are realized. For a specific operation principle, reference may be made to the description of the full-bridge secondary-side LC resonant converter in the prior art, and details thereof are not described herein.

It should be understood that when the voltage conversion circuit discharges the battery pack, the secondary side of the transformer TX1 connected to the LC resonant cavity is the high-voltage side of the voltage conversion circuit, and when the voltage conversion circuit charges the battery pack, the secondary side of the transformer TX1 connected to the first voltage conversion unit is the low-voltage side of the voltage conversion circuit.

Optionally, the high-voltage side of the transformer, the LC resonant cavity, and the second voltage conversion unit may also adopt the following connection modes:

fig. 25 is a first partial connection diagram of a voltage conversion circuit according to an embodiment of the present disclosure. As shown in fig. 25, the dotted terminal of the high-voltage side of the transformer TX1 is connected to the first terminal of the third capacitor Cr, the second terminal of the third capacitor Cr is connected to the midpoint of the sixth arm, the dotted terminal of the high-voltage side of the transformer TX1 is connected to the first terminal of the fifth inductor Lik, and the second terminal of the fifth inductor Lik is connected to the midpoint of the seventh arm.

Fig. 26 is a second partial connection schematic diagram of the voltage conversion circuit according to the embodiment of the present application. As shown in fig. 26, the dotted terminal of the high-voltage side of the transformer TX1 is connected to the first terminal of the third capacitor Cr, the second terminal of the third capacitor Cr is connected to the first terminal of the fifth inductor Lik, the second terminal of the fifth inductor Lik is connected to the midpoint of the sixth arm, and the dotted terminal of the high-voltage side of the transformer TX1 is connected to the midpoint of the seventh arm.

Fig. 27 is a schematic diagram of a partial connection of a voltage conversion circuit according to a third embodiment of the present disclosure. As shown in fig. 27, the dotted terminal on the high voltage side of the transformer TX1 is connected to the first terminal of the fifth inductor Lik, the second terminal of the fifth inductor Lik is connected to the first terminal of the third capacitor Cr, the second terminal of the third capacitor Cr is connected to the midpoint of the sixth arm, and the dotted terminal on the high voltage side of the transformer TX1 is connected to the midpoint of the seventh arm.

Fig. 28 is a schematic diagram illustrating a partial connection of a voltage conversion circuit according to an embodiment of the present disclosure. As shown in fig. 28, the dotted terminal of the high-voltage side of the transformer TX1 is connected to the midpoint of the sixth arm, the dotted terminal of the high-voltage side of the transformer TX1 is connected to the first terminal of the third capacitor Cr, the second terminal of the third capacitor Cr is connected to the first terminal of the fifth inductor Lik, and the second terminal of the fifth inductor Lik is connected to the midpoint of the seventh arm.

Fig. 29 is a partial connection schematic diagram of a voltage conversion circuit according to an embodiment of the present application. As shown in fig. 29, the dotted terminal of the high-voltage side of the transformer TX1 is connected to the midpoint of the sixth arm, the dotted terminal of the high-voltage side of the transformer TX1 is connected to the first terminal of the fifth inductor Lik, the second terminal of the fifth inductor Lik is connected to the first terminal of the third capacitor Cr, and the second terminal of the third capacitor Cr is connected to the midpoint of the seventh arm.

Fig. 30 is a schematic diagram illustrating a sixth partial connection of a voltage conversion circuit according to an embodiment of the present disclosure. As shown in fig. 30, a first end of a sixth arm (i.e., a second end of an eleventh switching tube Q11) is connected to a first different-name end of a high-voltage side of a transformer TX1, a second end of the sixth arm (i.e., a second end of a twelfth switching tube Q12) is connected to a second different-name end of the high-voltage side of the transformer TX1, a first end of the seventh arm (i.e., a second end of a thirteenth switching tube Q13) is connected to a first same-name end of the high-voltage side of the transformer TX1, a second end of the seventh arm (i.e., a second end of a fourteenth switching tube Q14) is connected to a second same-name end of the high-voltage side of the transformer TX1, a midpoint of the sixth arm is connected to a first end of a fifth inductor Lik, a second end of the fifth inductor Lik is connected to a first end of a third capacitor Cr, and a second end of the third capacitor Cr is connected to a midpoint of the seventh arm.

Fig. 31 is a schematic diagram illustrating a partial connection of a voltage conversion circuit according to an embodiment of the present application. As shown in fig. 31, a first end of the sixth arm (i.e., a second end of the eleventh switching tube Q11) is connected to a first different-name end of the high-voltage side of the transformer TX1, a second end of the sixth arm (i.e., a second end of the twelfth switching tube Q12) is connected to a second different-name end of the high-voltage side of the transformer TX1, a first end of the seventh arm (i.e., a second end of the thirteenth switching tube Q13) is connected to a first same-name end of the high-voltage side of the transformer TX1, a second end of the seventh arm (i.e., a second end of the fourteenth switching tube Q14) is connected to a second same-name end of the high-voltage side of the transformer TX1, a midpoint of the sixth arm is connected to a first end of the third capacitor Cr, a second end of the third capacitor Cr is connected to a first end of the fifth inductor Lik, and a second end of the fifth inductor Lik is connected to a midpoint of the seventh arm.

Optionally, the first voltage conversion unit may further adopt a structure as follows:

fig. 32 is a first schematic structural diagram of a first voltage conversion unit according to an embodiment of the present disclosure. As shown in fig. 32, in another implementation, the first voltage conversion unit may include: a seventh switching tube Q7 and an eighth switching tube Q8.

In this implementation, a first end of the seventh switching tube Q7 is connected to a first dotted end of the low voltage side of the transformer TX1, a first end of the eighth switching tube Q8 is connected to a dotted end of the low voltage side of the transformer TX1, and a second end of the seventh switching tube Q7 is connected to a second end of the eighth switching tube Q8.

The first end of the transformer TX1 with the same name as the low-voltage side is the first end of the voltage conversion circuit, and the second end of the seventh switch tube Q7 is the second end of the voltage conversion circuit. In some embodiments, the first voltage conversion unit shown in fig. 32 may also be referred to as a push-pull conversion circuit.

Fig. 33 is a second schematic structural diagram of the first voltage conversion unit according to the embodiment of the present application. As shown in fig. 33, in another implementation, the first voltage conversion unit may include: a seventh switch tube Q7, an eighth switch tube Q8 and a ninth switch tube Q9.

In this implementation, a first end of the seventh switching tube Q7 is connected to a first dotted terminal on the low voltage side of the transformer TX1, a first end of the ninth switching tube Q9 is connected to a second dotted terminal on the low voltage side of the transformer TX1, a first end of the eighth switching tube Q8 is connected to a dotted terminal on the low voltage side of the transformer TX1, and a second end of the seventh switching tube Q7 is connected to a second end of the eighth switching tube Q8.

The second terminal of the ninth switching tube Q9 is the first terminal of the voltage converting circuit, and the second terminal of the seventh switching tube Q7 is the second terminal of the voltage converting circuit.

In some embodiments, the first voltage conversion unit shown in fig. 33 may also be referred to as a three-transistor push-pull conversion circuit.

Fig. 34 is a third schematic structural diagram of the first voltage conversion unit according to the embodiment of the present application. As shown in fig. 34, in another implementation, the first voltage conversion unit may include: a fourth bridge arm, a fifth bridge arm and a fourth capacitor E4.

The fourth leg includes: a seventh switch tube Q7 and an eighth switch tube Q8 connected in series (i.e. the first end of the seventh switch tube Q7 is connected to the first end of the eighth switch tube Q8); the fifth leg includes: a ninth switching tube Q10 (i.e., the first end of the ninth switching tube Q9 is connected to the first end of the tenth switching tube Q10).

In this implementation, the second terminal of the seventh switching tube Q7 is the first terminal of the voltage conversion circuit, and the second terminal of the eighth switching tube Q8 is the second terminal of the voltage conversion circuit.

A first end of the fourth bridge arm (i.e., a second end of a seventh switching tube Q7) is connected to a first different-name end of a low-voltage side of the transformer TX1, a second end of the fourth bridge arm (i.e., a second end of an eighth switching tube Q8) is connected to a second different-name end of a low-voltage side of the transformer TX1, a first end of the fifth bridge arm (i.e., a second end of a ninth switching tube Q9) and a first end of the fourth capacitor E4 are both connected to a first same-name end of a low-voltage side of the transformer TX1, a second end of the fifth bridge arm (i.e., a second end of a tenth switching tube Q10) and a second end of the fourth capacitor E4 are both connected to a second same-name end of a low-voltage side of the transformer TX1, and a midpoint of the fourth bridge arm is connected to a midpoint of the fifth bridge arm.

In some embodiments, the first voltage conversion unit shown in fig. 34 may also be referred to as a full-bridge conversion circuit.

Fig. 35 is a fourth schematic structural diagram of the first voltage conversion unit according to the embodiment of the present application. As shown in fig. 35, if the battery pack of the three-arm topology device includes a first battery sub-pack and a second battery sub-pack connected in series. The negative electrode of the first battery sub-group is connected with the positive electrode of the second battery sub-group, the positive electrode of the first battery sub-group is the positive electrode of the battery pack, and the negative electrode of the second battery sub-group is the negative electrode of the battery pack. In this example, the first voltage conversion unit may include: a fourth bridge arm; the fourth leg includes: a seventh switch tube Q7 and an eighth switch tube Q8 connected in series (i.e., the first end of the seventh switch tube Q7 is connected to the first end of the eighth switch tube Q8).

The negative electrode of the first battery subgroup is connected with the different-name end of the low-voltage side of the transformer TX1, and the midpoint of the fourth bridge arm is connected with the same-name end of the low-voltage side of the transformer TX 1.

In some embodiments, the first voltage converting unit shown in fig. 35 may also be referred to as a half-bridge converting circuit.

It should be understood that, when the voltage conversion circuit is implemented by using any of the above-described modified schemes, the mode of the voltage conversion circuit operating when charging the battery pack and the mode of the voltage conversion circuit operating when discharging the battery pack are the same as those of the voltage conversion circuit shown in fig. 24, and details thereof are not repeated.

In addition, when the three-arm topology device of the B1 structure is adopted, the state of each switching tube in the external power supply mode of the three-arm topology device is similar to the state of each switching tube in the external power supply mode of the three-arm topology device shown in fig. 6. The current direction of the three-arm topology device is similar to the current direction of the three-arm topology device shown in fig. 6 in the external power supply mode, and specific reference may be made to the descriptions corresponding to fig. 8 to fig. 11, which are not described again.

Accordingly, in the battery power mode, the states of the switching tubes of the three-arm topology device in the battery power mode are similar to the states of the switching tubes of the three-arm topology device in the battery power mode shown in fig. 6. The current direction of the three-bridge-arm topology device is similar to that of the three-bridge-arm topology device shown in fig. 6 in the battery power supply mode, and specific reference may be made to the descriptions corresponding to fig. 12 to fig. 13, which are not described again.

Structure B2: the voltage conversion circuit in the three-bridge arm topology device realizes the voltage conversion function by multiplexing the second bridge arm of the three-bridge arm circuit and the bus capacitor E1 or only multiplexing the bus capacitor E1. The three-bridge-arm topological device can be applied to a battery low-voltage large-current inverter system and a battery low-voltage large-current UPS system. The external power supply of the UPS system can be a commercial power alternating current power supply AC, a photovoltaic PV direct current power supply + commercial power alternating current power supply AC and the like.

The structure B2 is described and introduced below by taking the application to a battery low-voltage large-current inverter system and a battery low-voltage large-current UPS system, respectively, as an example.

Structure B21: the UPS system is applied to the battery low-voltage large-current UPS system.

Fig. 36 is a schematic diagram of a seventeenth three-arm topology device according to an embodiment of the present application. As shown in fig. 36, taking the application of the three-arm topology device to a battery low-voltage high-current UPS system using a commercial AC power source AC as an external power supply as an example, the three-arm topology device shown in configuration B21 is different from the three-arm topology device shown in configuration B1 in the configuration of a voltage conversion circuit and the connection manner of the voltage conversion circuit and the three-arm circuit. The following description focuses on the differences:

Specifically, in the three-bridge-arm topology device shown in structure B21, the positive electrode of the battery pack is connected to the first end of the voltage conversion circuit, the negative electrode of the battery pack is connected to the second end of the voltage conversion circuit, the third end of the voltage conversion circuit is connected to BUS +, the fourth end of the voltage conversion circuit is connected to BUS-, and the fifth end of the voltage conversion circuit is connected to the midpoint of the second bridge arm. The voltage conversion circuit multiplexes a second bridge arm of the three-bridge arm circuit and a bus capacitor E1 to form a bidirectional DCDC topology, so that the function of bidirectional voltage conversion is realized.

In this embodiment, the three-bridge topology device also has two power supply modes, which are respectively: an external power mode and a battery power mode.

In an external power supply mode, a mains supply AC supplies power to the three-bridge-arm circuit, and the voltage conversion circuit is used for multiplexing a bidirectional DCDC topology formed by the second bridge arm and a bus capacitor E1 to charge the battery pack. At this time, the three-arm circuit operates in an AC-AC mode, the "bidirectional DCDC topology formed by the voltage conversion circuit multiplexing the second arm and the BUS capacitor E1" operates in a BUCK mode (i.e., a step-down mode), and the BUS voltage output by the dc BUS capacitor E1 is stepped down to obtain the charging voltage of the battery pack, so that the battery pack is charged by using the charging voltage. At this time, the battery pack serves as an output source of the bidirectional DCDC topology in which the voltage conversion circuit multiplexes the second arm and the bus capacitor E1.

In this way, in the external power supply mode, both the voltage conversion circuit and the three-bridge-arm circuit participate in operation, i.e., all devices of the three-bridge-arm topology device participate in operation. With respect to the technical effect of using the "bidirectional DCDC topology formed by multiplexing the second leg and the bus capacitor E1 by the voltage conversion circuit" to charge the battery pack, reference may be made to the description of using the voltage conversion circuit to charge the battery pack in fig. 2 in the foregoing embodiment.

In the battery power supply mode, the battery pack is an input source of a bidirectional DCDC topology formed by multiplexing the second bridge arm and the bus capacitor E1 by the voltage conversion circuit, and the output of the bidirectional DCDC topology formed by multiplexing the second bridge arm and the bus capacitor E1 by the voltage conversion circuit is used for supplying power for the three-bridge-arm circuit. That is, the "bidirectional DCDC topology in which the voltage conversion circuit multiplexes the second arm and the bus capacitor E1" discharges the battery pack. At this time, the bidirectional DCDC topology operates in a Boost mode (i.e., a Boost mode), the output voltage of the battery pack is boosted, and the boosted voltage is input to the dc bus capacitor E1 of the three-arm circuit to maintain the bus voltage balance. The boosted direct current is filtered by the direct current bus capacitor E1 to obtain stable direct current, a second bridge arm and a third bridge arm of the three-bridge-arm circuit work in an inversion mode, and the stable direct current is converted into alternating current and then output to a load to supply power to the load. Meanwhile, the direct current bus capacitor E1 can store energy. By the mode, in the battery power supply mode, the voltage conversion circuit and the three-bridge-arm circuit are both involved in working, namely all devices of the three-bridge-arm topological device are involved in working.

It can be understood that the voltage conversion circuit according to the embodiment of the present application may be a voltage conversion circuit with electrical isolation, or may be a voltage conversion circuit without electrical isolation.

With continued reference to fig. 36, the voltage conversion circuit according to the embodiment of the present application may include, for example: the device comprises a first voltage conversion unit, a transformer, an LC resonant cavity and a second voltage conversion unit. The first voltage conversion unit is connected with the low-voltage side of the transformer, and the high-voltage side of the transformer is connected with the LC resonant cavity and the second voltage conversion unit.

With continued reference to fig. 36, illustratively, the first voltage converting unit includes: a fourth bridge arm and a fifth bridge arm. The LC resonant cavity includes: a fifth inductance Lik and an inductance Cr. The second voltage conversion unit includes: and a sixth bridge arm. That is, the second voltage converting unit involved in this embodiment is a half-bridge topology.

Wherein the fourth leg comprises: a seventh switch tube Q7 and an eighth switch tube Q8 connected in series (i.e., the first end of the seventh switch tube Q7 is connected to the first end of the eighth switch tube Q8); the fifth leg includes: a ninth switching tube Q9 and a tenth switching tube Q10 connected in series (i.e., the first end of the ninth switching tube Q9 is connected to the first end of the tenth switching tube Q10). The fourth leg is connected in parallel with the fifth leg (i.e., the second end of the seventh switching tube Q7 is connected to the second end of the ninth switching tube Q9, and the second end of the eighth switching tube Q8 is connected to the second end of the tenth switching tube Q10).

The sixth bridge arm includes: an eleventh switch tube Q11 and a twelfth switch tube Q12 connected in series (i.e., the first end of the eleventh switch tube Q11 is connected to the first end of the twelfth switch tube Q12). The sixth bridge arm is connected in parallel between BUS + and BUS- (i.e., the second end of the eleventh switch tube Q11 is connected with BUS +, and the second end of the twelfth switch tube Q12 is connected with BUS-).

For the description of the fourth bridge arm, the fifth bridge arm, the sixth bridge arm and the LC resonant cavity, reference may be made to the description of the fourth bridge arm, the fifth bridge arm, the sixth bridge arm and the LC resonant cavity in fig. 3, and details are not repeated here. In some embodiments, the first voltage conversion unit shown in fig. 36 may also be referred to as a full-bridge conversion circuit.

The second terminal of the seventh switch tube Q7 is the first terminal of the voltage conversion circuit, the second terminal of the eighth switch tube Q8 is the second terminal of the voltage conversion circuit, the second terminal of the eleventh switch tube Q11 is the third terminal of the voltage conversion circuit, and the second terminal of the twelfth switch tube Q12 is the fourth terminal of the voltage conversion circuit.

The middle point of the fourth bridge arm is connected with the different-name end of the low-voltage side of the transformer TX1, and the middle point of the fifth bridge arm is connected with the same-name end of the low-voltage side of the transformer TX 1. The dotted end of the high-voltage side of the transformer is connected with the first end of the fifth inductor Lik, the second end of the fifth inductor Lik is connected with the midpoint of the sixth bridge arm, the dotted end of the high-voltage side of the transformer is connected with the first end of the third capacitor Cr, and the second end of the third capacitor Cr is connected with the midpoint of the second bridge arm. Namely, the second terminal of the third capacitor Cr is the fifth terminal of the voltage conversion circuit.

When the voltage conversion circuit is used for charging the battery pack, the bidirectional DCDC topology formed by the voltage conversion circuit multiplexing the second bridge arm and the bus capacitor E1 works in a half-bridge LLC resonant converter mode. That is, the LC resonant cavity and an inductor (not shown in the figure) in the transformer TX1 form an LLC resonant network, so that the bidirectional DCDC topology forms a half-bridge LLC resonant converter, and voltage regulation in a wider range and zero-voltage switching-on are realized.

When the voltage conversion circuit is adopted to discharge the battery pack, the bidirectional DCDC topology formed by multiplexing the second bridge arm and the bus capacitor E1 by the voltage conversion circuit works in a full-bridge secondary side LC resonance voltage-multiplying converter mode, namely, a secondary side of the transformer TX1 and an LC resonant cavity form a voltage-multiplying rectifying circuit, so that the bidirectional DCDC topology forms the full-bridge secondary side LC resonance voltage-multiplying converter, the output voltage of the bidirectional DCDC topology is twice of the secondary side voltage of the transformer TX1, the purpose of twice boosting is achieved, and the boosting ratio of the bidirectional DCDC topology is improved.

Specifically, in the positive half cycle of the secondary side output voltage V2 of the transformer TX1, the third capacitor Cr of the resonant cavity stores energy. At this time, the voltage of the third capacitor Cr may reach 2 times the root of the peak value of V2 and remain unchanged. In the negative half cycle of the output voltage V2 at the secondary side of the transformer TX1, the secondary side of the transformer TX1 and the third capacitor Cr of the resonant cavity simultaneously provide output voltage, so that the output voltage of the bidirectional DCDC topology reaches 2 times of the root sign V2 peak value and keeps unchanged. At this time, the output voltage of the bidirectional DCDC topology is 2 times of the secondary side voltage of the transformer TX 1.

For example, taking the output voltage of the bidirectional DCDC topology as 200V as an example, in the above full-bridge secondary LC resonant voltage-doubling converter mode, the transformer TX1 only needs to raise the voltage output by the battery pack to 100V, so that the output voltage of the bidirectional DCDC topology can reach 200V.

It should be understood that the secondary side of the transformer TX1 connected to the LC tank is the high-voltage side of the voltage conversion circuit when discharging the battery pack, and the secondary side of the transformer TX1 connected to the first voltage conversion unit is the low-voltage side of the voltage conversion circuit when charging the battery pack.

Optionally, the high voltage side of the transformer, the LC resonant cavity, the second voltage conversion unit, and the second bridge arm may also adopt a connection manner as shown in fig. 25 to fig. 31. The only difference is that when the connection method shown in fig. 25 to 31 is applied to the present embodiment, the second arm is used instead of the seventh arm in fig. 25 to 31. In these implementation manners, the end of the voltage conversion circuit connected to the midpoint of the second bridge arm is the fifth end of the voltage conversion circuit, which is not described again.

Fig. 36A is a schematic diagram eight of a partial connection of the voltage conversion circuit provided in the embodiment of the present application, and fig. 36B is a schematic diagram nine of a partial connection of the voltage conversion circuit provided in the embodiment of the present application. Referring to fig. 36A and 36B, when the high-voltage side of the transformer, the LC resonant cavity, the second voltage conversion unit, and the second bridge arm adopt the connection manner shown in fig. 30 or 31, the first end with the same name of the high-voltage side of the transformer TX1 is the third end of the voltage conversion circuit, and the second end with the same name of the high-voltage side of the transformer TX1 is the fourth end of the voltage conversion circuit, which is not described again. At this time, the connection manner between the high-voltage side of the transformer and the LC resonant cavity, the second voltage conversion unit, and the second bridge arm may be as shown in fig. 36A or fig. 36B, for example.

Accordingly, the first voltage converting unit according to this embodiment may also be replaced by the structure shown in fig. 32 to fig. 35, which is not described again.

It should be understood that, when the voltage conversion circuit is implemented by using any of the above-described modified schemes, "the mode of the voltage conversion circuit operating in charging the battery pack and the mode of the bidirectional DCDC topology constituted by multiplexing the second bridge arm and the bus capacitor E1" are the same as those of the voltage conversion circuit shown in fig. 36, and details thereof are not repeated.

The following takes the structure of the three-arm topology device shown in fig. 36 as an example, and schematically illustrates the states of the switches, the states of the switching tubes, and the current directions of the three-arm topology device in different power supply modes:

fig. 37 is a first current schematic diagram of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode. As shown in fig. 37, in the first phase of the external power supply mode, that is, in the first phase of the positive half cycle of the input ac power (i.e., the ac power input through the positive voltage input terminal and the negative voltage input terminal of the three-bridge arm topology device), the second switching tube Q2, the fourth switching tube Q4, the fifth switching tube Q5 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. BUS + → fifth switching tube Q5 → second inductor L2 → first capacitor Co → fourth switching tube Q4 → BUS-, to provide energy to the load through BUS capacitor E1. The second inductor L2 and the first capacitor Co are used to implement a filtering function.

3. BUS + → eleventh switching tube Q11 → fifth inductance Lik → TX1 high-voltage side dotted terminal → TX1 high-voltage side synonym terminal → third capacitance Cr → fourth switching tube Q4 → BUS-, so that BUS capacitance E1 transmits energy for transformer TX1, and constitutes an energy storage loop of third capacitance Cr. The dotted terminal on the low-voltage side of TX1 → the ninth switching tube Q9 → the positive electrode of the battery pack → the negative electrode of the battery pack → the eighth switching tube Q8 → the dotted terminal on the low-voltage side of TX1, which constitutes the energy storage circuit of the battery pack. The ninth switching tube Q9 and the eighth switching tube Q8 are used for achieving a rectifying function.

Fig. 38 is a current schematic diagram two of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode. As shown in fig. 38, in the second phase of the external power supply mode, that is, in the second phase of the positive half cycle of the input ac power, the second switching tube Q2, the fourth switching tube Q4, the fifth switching tube Q5 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The live line of the commercial power alternating-current power supply AC → the first inductor L1 → the second switching tube Q2 → the fourth switching tube Q4 → the zero line of the commercial power alternating-current power supply AC constitutes a tank circuit of the first inductor L1.

3. The Cr positive pole → the synonym end on the high-voltage side of TX1 → the synonym end on the high-voltage side of TX1 → the fifth inductor Lik → the twelfth switching tube Q12 → the fourth switching tube Q4 → the Cr negative pole, so that the Cr transmits energy for the transformer TX 1. The different name end on the low-voltage side of the TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the same name end on the low-voltage side of the TX1, and a storage circuit of the battery pack is formed. The seventh switch tube Q7 and the tenth switch tube Q10 are used for realizing a rectification function.

Fig. 39 is a current schematic diagram third of a seventeenth three-bridge-arm topology device according to the embodiment of the present application in an external power supply mode. As shown in fig. 39, in the third phase of the external power supply mode, that is, in the third phase of the positive half cycle of the input ac power, the fourth switching tube Q4, the fifth switching tube Q5 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The live wire of the commercial power alternating-current power supply AC → the first inductor L1 → the first switching tube Q1 → the bus capacitor E1 → the fourth switching tube Q4 → the zero line of the commercial power alternating-current power supply AC, and the energy storage loop of the bus capacitor E1 is formed. At this time, the mains supply and the first inductor L1 simultaneously supply energy to the bus capacitor E1.

Fig. 40 is a current schematic diagram of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode. As shown in fig. 40, in the fourth phase of the external power supply mode, that is, in the fourth phase of the positive half cycle of the input ac power, the fourth switching tube Q4, the fifth switching tube Q5 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

3. The Cr positive pole → the synonym terminal at the high-voltage side of TX1 → the synonym terminal at the high-voltage side of TX1 → the fifth inductor Lik → the twelfth switching tube Q12 → the fourth switching tube Q4 → the Cr negative pole, so that the Cr is the transformer TX1 to transmit energy. The different name end on the low-voltage side of the TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the same name end on the low-voltage side of the TX1, and a storage circuit of the battery pack is formed. The seventh switch tube Q7 and the tenth switch tube Q10 are used for realizing a rectification function.

Fig. 41 is a fifth current schematic diagram of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode. As shown in fig. 41, in the fifth phase of the external power supply mode, that is, in the fifth phase of the positive half cycle of the input ac power, the second switching tube Q2, the fourth switching tube Q4, the sixth switching tube Q6 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. The second inductor L2 → the first capacitor Co → the fourth switching tube Q4 → the sixth switching tube Q6 → the second inductor L2, so as to provide energy to the load through the second inductor L2. The second inductor L2 and the first capacitor Co are used to implement a filtering function.

3. BUS + → an eleventh switching tube Q11 → a fifth inductor Lik → a dotted terminal on the high-voltage side of TX1 → a different terminal on the high-voltage side of TX1 → a third capacitor Cr → a fourth switching tube Q4 → BUS-, so that the BUS capacitor E1 transmits energy for the transformer TX1, and an energy storage loop of the third capacitor Cr is formed. The dotted terminal on the low-voltage side of TX1 → the ninth switching tube Q9 → the positive electrode of the battery pack → the negative electrode of the battery pack → the eighth switching tube Q8 → the dotted terminal on the low-voltage side of TX1, which constitutes the energy storage circuit of the battery pack. The ninth switching tube Q9 and the eighth switching tube Q8 are used for achieving a rectifying function.

Fig. 42 is a sixth current schematic diagram of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode. As shown in fig. 42, in the sixth phase of the external power supply mode, that is, in the sixth phase of the positive half cycle of the input ac power, the second switching tube Q2, the fourth switching tube Q4, the sixth switching tube Q6 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

3. The Cr positive pole → the synonym terminal at the high-voltage side of TX1 → the synonym terminal at the high-voltage side of TX1 → the fifth inductor Lik → the twelfth switching tube Q12 → the fourth switching tube Q4 → the Cr negative pole, so that the Cr is the transformer TX1 to transmit energy. The synonym end of the low-voltage side of TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the synonym end of the low-voltage side of TX1 constitutes an energy storage loop of the battery pack. The seventh switch tube Q7 and the tenth switch tube Q10 are used for realizing a rectification function.

Fig. 43 is a current schematic diagram seven of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode. As shown in fig. 43, in the seventh phase of the external power supply mode, that is, in the seventh phase of the positive half cycle of the input ac power, the fourth switching tube Q4, the sixth switching tube Q6 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

3. BUS + → eleventh switching tube Q11 → fifth inductance Lik → TX1 high-voltage side dotted terminal → TX1 high-voltage side synonym terminal → third capacitance Cr → fourth switching tube Q4 → BUS-, so that BUS capacitance E1 transmits energy for transformer TX1, and constitutes an energy storage loop of third capacitance Cr. The dotted terminal on the low-voltage side of TX1 → the ninth switching tube Q9 → the positive electrode of the battery pack → the negative electrode of the battery pack → the eighth switching tube Q8 → the dotted terminal on the low-voltage side of TX1, which forms a storage circuit of the battery pack. The ninth switching tube Q9 and the eighth switching tube Q8 are used for achieving a rectifying function.

Fig. 44 is a current schematic diagram eight of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode. As shown in fig. 44, in the eighth phase of the external power supply mode, that is, in the eighth phase of the positive half cycle of the input ac power, the fourth switching tube Q4, the sixth switching tube Q6 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

3. The Cr positive pole → the synonym terminal at the high-voltage side of TX1 → the synonym terminal at the high-voltage side of TX1 → the fifth inductor Lik → the twelfth switching tube Q12 → the fourth switching tube Q4 → the Cr negative pole, so that the Cr is the transformer TX1 to transmit energy. The synonym end of the low-voltage side of TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the synonym end of the low-voltage side of TX1 constitutes an energy storage loop of the battery pack. The seventh switching tube Q7 and the tenth switching tube Q10 are used for achieving a rectification function.

Fig. 45 is a current schematic diagram nine of a seventeenth three-arm topology device according to an embodiment of the present application in an external power supply mode. As shown in fig. 45, in the ninth phase of the external power supply mode, that is, in the first phase of the negative half cycle of the input alternating current, the first switching tube Q1, the third switching tube Q3, the sixth switching tube Q6 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. BUS + → third switch tube Q3 → first capacitor Co → second inductor L2 → sixth switch tube Q6 → BUS-, to provide energy to the load through BUS capacitor E1. The second inductor L2 and the first capacitor Co are used to implement a filtering function.

3. BUS + → third switching tube Q3 → third capacitor Cr → synonym terminal of TX1 high-voltage side → synonym terminal of TX1 high-voltage side → fifth inductor Lik → twelfth switching tube Q12 → BUS-, so that BUS capacitor E1 transmits energy for transformer TX1, and an energy storage loop of third capacitor Cr is formed. The different name end on the low-voltage side of the TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the same name end on the low-voltage side of the TX1, and a storage circuit of the battery pack is formed. The seventh switch tube Q7 and the tenth switch tube Q10 are used for realizing a rectification function.

Fig. 46 is a current schematic diagram ten of a seventeenth three-bridge-arm topology device provided in the embodiment of the present application in an external power supply mode. As shown in fig. 46, in the tenth phase of the external power supply mode, i.e., in the second phase of the negative half cycle of the input ac power, the first switch Q1, the third switch Q3, the sixth switch Q6 and the eleventh switch Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. BUS + → third switching tube Q3 → first capacitor Co → second inductor L2 → sixth switching tube Q6 → BUS-, to provide energy to the load through BUS capacitor E1. The second inductor L2 and the first capacitor Co are used to implement a filtering function.

3. The Cr positive pole → the third switching tube Q3 → the eleventh switching tube Q11 → the fifth inductor Lik → the dotted terminal on the high-voltage side of TX1 → the different terminal on the high-voltage side of TX1 → the Cr negative pole, so that the Cr transmits energy to the transformer TX 1. The dotted terminal on the low-voltage side of TX1 → the ninth switching tube Q9 → the positive electrode of the battery pack → the negative electrode of the battery pack → the eighth switching tube Q8 → the dotted terminal on the low-voltage side of TX1, which constitutes the energy storage circuit of the battery pack. The ninth switching tube Q9 and the eighth switching tube Q8 are used for achieving a rectification function.

Fig. 47 is a schematic current diagram eleven of a seventeenth three-bridge-arm topology device provided in an embodiment of the present application in an external power supply mode. As shown in fig. 47, in the eleventh phase of the external power supply mode, that is, in the third phase of the negative half cycle of the input ac power, the third switching tube Q3, the sixth switching tube Q6 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The neutral line of the commercial power alternating-current power supply AC → the third switching tube Q3 → the bus capacitor E1 → the second switching tube Q2 → the first inductor L1 → the live wire of the commercial power alternating-current power supply AC, and the energy storage loop of the bus capacitor E1 is formed. At this time, the commercial power and the first inductor L1 simultaneously supply energy to the bus capacitor E1.

3. BUS + → third switching tube Q3 → third capacitor Cr → synonym terminal of TX1 high-voltage side → synonym terminal of TX1 high-voltage side → fifth inductor Lik → twelfth switching tube Q12 → BUS-, so that BUS capacitor E1 transmits energy for transformer TX1, and an energy storage loop of third capacitor Cr is formed. The synonym end of the low-voltage side of TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the synonym end of the low-voltage side of TX1 constitutes an energy storage loop of the battery pack. The seventh switch tube Q7 and the tenth switch tube Q10 are used for realizing a rectification function.

Fig. 48 is a current schematic diagram twelve of a seventeenth three-arm topology device provided in the embodiment of the present application in an external power supply mode. As shown in fig. 48, in the twelfth phase of the external power supply mode, that is, in the fourth phase of the negative half cycle of the input alternating current, the third switching tube Q3, the sixth switching tube Q6 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The neutral line of the commercial power alternating-current power supply AC → the third switching tube Q3 → the bus capacitor E1 → the second switching tube Q2 → the first inductor L1 → the live line of the commercial power alternating-current power supply AC, and the energy storage loop of the bus capacitor E1 is formed. At this time, the mains supply and the first inductor L1 simultaneously supply energy to the bus capacitor E1.

3. The Cr positive pole → the third switching tube Q3 → the eleventh switching tube Q11 → the fifth inductor Lik → the dotted terminal on the high-voltage side of TX1 → the different terminal on the high-voltage side of TX1 → the Cr negative pole, so that the Cr transmits energy to the transformer TX 1. The dotted terminal on the low-voltage side of TX1 → the ninth switching tube Q9 → the positive electrode of the battery pack → the negative electrode of the battery pack → the eighth switching tube Q8 → the dotted terminal on the low-voltage side of TX1, which constitutes the energy storage circuit of the battery pack. The ninth switching tube Q9 and the eighth switching tube Q8 are used for achieving a rectifying function.

Fig. 49 is a schematic current diagram thirteenth of a seventeenth three-arm topology device provided in the embodiment of the present application in an external power supply mode. As shown in fig. 49, in the thirteenth phase of the external power supply mode, that is, in the fifth phase of the negative half cycle of the input ac power, the first switch tube Q1, the third switch tube Q3, the fifth switch tube Q5 and the twelfth switch tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. The second inductor L2 → the fifth switching tube Q5 → the third switching tube Q3 → the first capacitor Co → the second inductor L2, so as to provide energy to the load through the second inductor L2. The second inductor L2 and the first capacitor Co are used to implement a filtering function.

Fig. 50 is a fourteenth current schematic diagram of a seventeenth three-bridge-arm topology device in an external power supply mode according to an embodiment of the present application. As shown in fig. 50, in the fourteenth phase of the external power supply mode, that is, in the sixth phase of the negative half cycle of the input ac power, the first switching tube Q1, the third switching tube Q3, the fifth switching tube Q5 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

Fig. 51 is a schematic current diagram fifteen illustrating a seventeenth three-arm topology device according to an embodiment of the present application in an external power supply mode. As shown in fig. 51, in the fifteenth phase of the external power supply mode, that is, in the seventh phase of the negative half cycle of the input alternating current, the third switching tube Q3, the fifth switching tube Q5 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. The second inductor L2 → the fifth switch Q5 → the third switch Q3 → the first capacitor Co → the second inductor L2, so as to provide energy to the load through the second inductor L2. The second inductor L2 and the first capacitor Co are used to implement a filtering function.

3. BUS + → third switching tube Q3 → third capacitor Cr → synonym terminal of the high-voltage side of TX1 → dotted terminal of the high-voltage side of TX1 → fifth inductor Lik → twelfth switching tube Q12 → BUS-, so that the BUS capacitor E1 transmits energy for the transformer TX1, and an energy storage loop of the third capacitor Cr is formed. The synonym end of the low-voltage side of TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the synonym end of the low-voltage side of TX1 constitutes an energy storage loop of the battery pack. The seventh switch tube Q7 and the tenth switch tube Q10 are used for realizing a rectification function.

Fig. 52 is a sixteenth schematic current diagram of a seventeenth three-arm topology device according to the embodiment of the present application in an external power supply mode. As shown in fig. 52, in the sixteenth phase of the external power supply mode, that is, in the eighth phase of the negative half cycle of the input ac power, the third switching tube Q3, the fifth switching tube Q5 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The neutral line of the commercial power alternating-current power supply AC → the third switching tube Q3 → the bus capacitor E1 → the second switching tube Q2 → the first inductor L1 → the live wire of the commercial power alternating-current power supply AC, and the energy storage loop of the bus capacitor E1 is formed. At this time, the mains supply and the first inductor L1 simultaneously supply energy to the bus capacitor E1.

Fig. 53 is a first current schematic diagram of a seventeenth three-arm topology device in a battery-powered mode according to the embodiment of the present application. As shown in fig. 53, in the first phase of the battery power supply mode, that is, in the first phase of the positive half cycle of the output alternating current (i.e., the alternating current output through the first output terminal and the second output terminal of the three-bridge arm topology device), the fourth switching tube Q4, the fifth switching tube Q5, the seventh switching tube Q7, the tenth switching tube Q10 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The positive pole of the battery pack → the seventh switching tube Q7 → the synonym end of the low-voltage side of TX1 → the synonym end of the low-voltage side of TX1 → the tenth switching tube Q10 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The synonym terminal of the high-voltage side of TX1 → the third capacitor Cr → the fourth switching tube Q4 → the twelfth switching tube Q12 → the fifth inductor Lik → the synonym terminal of the high-voltage side of TX1 constitute an energy storage loop of the third capacitor Cr.

Fig. 54 is a current schematic diagram two of a seventeenth three-arm topology device according to the embodiment of the present application in a battery power supply mode. As shown in fig. 54, in the second phase of the battery power supply mode, that is, in the second phase of the positive half cycle of the output alternating current, the fourth switching tube Q4, the fifth switching tube Q5, the eighth switching tube Q8, the ninth switching tube Q9 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the ninth switching tube Q9 → the homonymous terminal of the low-voltage side of the TX1 → the synonym terminal of the low-voltage side of the TX1 → the eighth switching tube Q8 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The dotted terminal on the high-voltage side of the TX1 → the fifth inductor Lik → the eleventh switching tube Q11 → BUS + → BUS- → the fourth switching tube Q4 → the third capacitor Cr → the synonym terminal on the high-voltage side of the TX1 constitute an energy storage loop of the BUS capacitor E1. At this time, the transformer TX1 and the third capacitor Cr simultaneously supply energy to the bus capacitor E1.

Fig. 55 is a current schematic diagram third of a seventeenth three-arm topology device in a battery-powered mode according to the embodiment of the present application. As shown in fig. 55, in the third phase of the battery powered mode, that is, in the third phase of the positive half cycle of the output ac power, the fourth switching tube Q4, the sixth switching tube Q6, the seventh switching tube Q7, the tenth switching tube Q10 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the seventh switching tube Q7 → the synonym end of the low-voltage side of TX1 → the synonym end of the low-voltage side of TX1 → the tenth switching tube Q10 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The different-name end on the high-voltage side of TX1 → the third capacitor Cr → the fourth switching tube Q4 → the twelfth switching tube Q12 → the fifth inductor Lik → the same-name end on the high-voltage side of TX1 form a storage loop of the third capacitor Cr.

Fig. 56 is a fourth current schematic diagram of a seventeenth three-arm topology device in a battery-powered mode according to the embodiment of the present application. As shown in fig. 56, in the fourth phase of the battery power supply mode, that is, in the fourth phase of the positive half cycle of the output alternating current, the fourth switching tube Q4, the sixth switching tube Q6, the eighth switching tube Q8, the ninth switching tube Q9 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

Fig. 57 is a fifth current schematic diagram of a seventeenth three-arm topology device in a battery-powered mode according to the embodiment of the present application. As shown in fig. 57, in the fifth phase of the battery power supply mode, i.e. in the first phase of the negative half cycle of the output alternating current, the third switching tube Q3, the sixth switching tube Q6, the seventh switching tube Q7, the tenth switching tube Q10 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the seventh switching tube Q7 → the synonym end of the low-voltage side of TX1 → the synonym end of the low-voltage side of TX1 → the tenth switching tube Q10 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The unlike terminal on the high-voltage side of the TX1 → the third capacitor Cr → the third switching tube Q3 → BUS + → BUS- → the twelfth switching tube Q12 → the fifth inductor Lik → the like terminal on the high-voltage side of the TX1 constitute an energy storage loop of the BUS capacitor E1. At this time, the transformer TX1 and the third capacitor Cr simultaneously supply energy to the bus capacitor E1.

Fig. 58 is a sixth schematic current diagram of a seventeenth three-arm topology device in a battery-powered mode according to an embodiment of the present application. As shown in fig. 58, in the sixth phase of the battery power supply mode, that is, in the second phase of the negative half cycle of the output alternating current, the third switching tube Q3, the sixth switching tube Q6, the eighth switching tube Q8, the ninth switching tube Q9 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the ninth switching tube Q9 → the homonymous terminal of the low-voltage side of the TX1 → the synonym terminal of the low-voltage side of the TX1 → the eighth switching tube Q8 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The homonymous terminal on the high-voltage side of the TX1 → the fifth inductor Lik → the eleventh switch tube Q11 → the third switch tube Q3 → the third capacitor Cr → the synonym terminal on the high-voltage side of the TX1, and a storage circuit of the third capacitor Cr is formed.

Fig. 59 is a current schematic diagram seventh of a seventeenth three-arm topology device according to the embodiment of the present application in a battery power supply mode. As shown in fig. 59, in the seventh phase of the battery power supply mode, that is, in the third phase of the negative half cycle of the output alternating current, the third switching tube Q3, the fifth switching tube Q5, the seventh switching tube Q7, the tenth switching tube Q10 and the twelfth switching tube Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

Fig. 60 is a current schematic diagram eight of a seventeenth three-arm topology device in a battery-powered mode according to the embodiment of the present application. As shown in fig. 60, in the eighth phase of the battery power supply mode, that is, in the fourth phase of the negative half cycle of the output alternating current, the third switching tube Q3, the fifth switching tube Q5, the eighth switching tube Q8, the ninth switching tube Q9 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The positive pole of the battery pack → the ninth switching tube Q9 → the homonymous terminal of the low-voltage side of the TX1 → the synonym terminal of the low-voltage side of the TX1 → the eighth switching tube Q8 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The dotted terminal on the high-voltage side of TX1 → the fifth inductor Lik → the eleventh switching tube Q11 → the third switching tube Q3 → the third capacitor Cr → the dotted terminal on the high-voltage side of TX1 constitute the tank circuit of the third capacitor Cr.

Although the above example is applied to a battery low-voltage high-current UPS system in which a commercial AC power supply AC is used as an external power supply, the three-bridge topology apparatus provided in the present embodiment is exemplified. However, it will be appreciated by those skilled in the art that the three-bridge topology arrangement may also be applied to UPS systems using other external power supplies.

Fig. 61 is a schematic diagram of an eighteenth three-leg topology device provided in the embodiment of the present application. For example, the commercial AC power source AC in fig. 36 may be replaced by a photovoltaic PV dc power source, resulting in a three-bridge arm topology device as shown in fig. 61. At this time, the three-bridge topology apparatus of the B21 structure shown in fig. 61 can be applied to a battery low-voltage large-current UPS system using a photovoltaic PV dc power source as an external power supply source.

In this application scenario, the second terminal of the first inductor L1 serves as the positive voltage input PV + of the three-bridge topology device. BUS-is used as a negative voltage input PV-of the three-bridge arm topological device. The positive pole of the photovoltaic PV direct current power supply is connected with the positive voltage input end PV +, and the negative pole of the photovoltaic PV direct current power supply is connected with the negative voltage input end PV-.

Optionally, in some embodiments, the positive pole of the photovoltaic PV dc power supply is connected to the positive voltage input PV + through a switch K6 to meet the safety requirements for the three-bridge arm topology device. It should be understood that the switch K6 may be, for example, a unidirectional electronic switch, a triac, or the like.

It should be understood that the working principle and technical effects of the three-arm topology device shown in fig. 61 can be referred to the description of the three-arm topology device in fig. 36, and the description thereof is omitted.

Fig. 62 is a schematic diagram of a nineteenth three-bridge-arm topology device according to an embodiment of the present application. For example, on the basis of fig. 36, a photovoltaic PV dc power supply, an eighth bridge arm, and a sixth inductor L6 may be added to the three-bridge-arm topology apparatus. At this time, the three-bridge topology apparatus of B21 structure shown in fig. 62 can be applied to a battery low-voltage large-current UPS system using the PV dc power supply + the AC mains power supply AC as an external power supply.

The eighth bridge arm comprises a seventeenth switching tube Q17 and an eighteenth switching tube Q18, and the seventeenth switching tube Q17 and the eighteenth switching tube Q18 are connected between BUS + and BUS-in series. For example, a first end of the seventeenth switching tube Q17 is connected to BUS +, a second end of the seventeenth switching tube Q17 is connected to a first end of the eighteenth switching tube Q18, and a second end of the eighteenth switching tube Q18 is connected to BUS-. The common end of the seventeenth switching tube Q17 and the eighteenth switching tube Q18 is referred to as the midpoint of the eighth arm. That is, the eighth arm is connected in parallel with bus capacitor E1 between the bus positive output terminal and the bus negative output terminal. Through the eighth bridge arm, the output voltage or current of the photovoltaic PV direct-current Power supply can be changed, so that the photovoltaic PV direct-current Power supply works at the Maximum Power Point, and Maximum Power Point Tracking (MPPT for short) of the photovoltaic PV direct-current Power supply is realized.

The second terminal of the first inductor L1 serves as a first positive voltage input terminal AC _ L of the three-bridge topology device. And the middle point of the second bridge arm is used as a first negative voltage input end AC _ N of the three-bridge-arm topological device. The live wire of the commercial power alternating current power supply AC is connected with the first positive voltage input end AC _ L, and the zero wire of the commercial power alternating current power supply AC is connected with the first negative voltage input end AC _ N.

The midpoint of the eighth bridge leg is connected to the first end of the sixth inductor L6, and the second end of the sixth inductor L6 serves as the second positive voltage input PV + of the three-bridge-leg topology device. And the negative output end of the bus is used as a second negative voltage input end PV-of the three-bridge-arm topological device. The positive pole of the photovoltaic PV direct current power supply is connected with the second positive voltage input end PV +, and the negative pole of the photovoltaic PV direct current power supply is connected with the second negative voltage input end PV-.

Optionally, in some embodiments, the positive electrode of the photovoltaic PV dc power supply is connected to the second positive voltage input PV + through a switch K6 to meet the safety requirements for the three-bridge arm topology device. It should be understood that the switch K6 may be, for example, a unidirectional electronic switch, a triac, or the like.

Optionally, the photovoltaic PV dc power supply and the commercial AC power supply AC are backup power supplies for each other, and in the specific implementation, the photovoltaic PV dc power supply and/or the commercial AC power supply AC may be selected as an external power supply source of the three-bridge-arm topology device according to actual requirements, which is not limited.

In the application scenario provided by this embodiment, the working principle and the technical effect of the three-bridge-arm topology device shown in fig. 62 can be referred to the description of the three-bridge-arm topology device in fig. 36, which is not described again.

In addition, the current flow of the three-arm topology devices shown in fig. 37 to 60 is schematically described by taking the seventeenth three-arm topology device shown in fig. 36 as an example. However, it can be understood by those skilled in the art that the current direction, and the states of the switches and the switch tubes are also applicable to the three-arm topology device shown in fig. 61 and 62, and the implementation principle is similar, and thus the detailed description is omitted.

Structure B22: the inverter is applied to a battery low-voltage large-current inverter system.

Fig. 63 is a schematic diagram of a twentieth three-bridge-arm topology device according to an embodiment of the present application. As shown in fig. 63, in this embodiment, the first terminal of the first capacitor Co is the first external connection terminal of the three-arm topology device, and the second terminal of the first capacitor Co is the second external connection terminal of the three-arm topology device.

When discharging the battery pack, the first external connection terminal may be referred to as a first output terminal of the three-arm topology device, and the second external connection terminal may be referred to as a second output terminal of the three-arm topology device, which are both connected to the load. When charging the battery pack, the first external connection terminal may be referred to as a positive voltage input terminal of the three-bridge topology device and connected to a first terminal of the external power supply source, and the second external connection terminal may be referred to as a negative voltage input terminal of the three-bridge topology device and connected to a second terminal of the external power supply source.

For example, taking the external power supply as a photovoltaic dc power supply as an example, the first end of the external power supply is a positive electrode of the photovoltaic dc power supply, and the second end of the external power supply is a negative electrode of the photovoltaic dc power supply. Taking the external power supply as an alternating current mains supply as an example, the first end of the external power supply is a live wire of the alternating current mains supply, and the second end of the external power supply is a zero line of the alternating current mains supply.

Taking the external power supply as an AC mains supply as an example, the AC mains supply and the load are respectively connected to the first end of the first capacitor Co and the second end of the first capacitor Co through a relay. When discharging the battery pack, the relay conducts a path between the load and the first capacitor Co. When the battery pack is charged, the relay conducts a path between the commercial power alternating current power supply AC and the first capacitor Co.

For ease of description, the figure is denoted AC. It should be understood that when discharging the battery pack, AC herein characterizes the alternating current output by the three-arm topology. When charging the battery pack, the AC herein characterizes the mains alternating current supply AC that supplies power to the three-bridge arm topology.

The positive pole of the battery pack is connected with the first end of the voltage conversion circuit, and the negative pole of the battery pack is connected with the second end of the voltage conversion circuit. The third end of the voltage conversion circuit is connected with a BUS +, the fourth end of the voltage conversion circuit is connected with a BUS-, and the fifth end of the voltage conversion circuit is connected with the midpoint of the first bridge arm.

In this embodiment, the voltage conversion circuit, the first arm of the three-arm circuit, and the bus capacitor E1 form a bidirectional DCDC topology (which may also be referred to as a bidirectional DCDC converter) to realize a bidirectional voltage conversion function. The bus capacitor E1, the second bridge arm, the third bridge arm and the LC filter of the three-bridge arm circuit form a bidirectional DCAC topology (also called a bidirectional DCAC converter) to realize an inversion or rectification function. That is, the bidirectional DCDC topology and the bidirectional DCAC topology multiplex the bus capacitance E1 of the three-arm circuit.

In this embodiment, the three-arm topology device has two modes, which are: a battery charging mode and a battery powered mode.

In the battery charging mode, a commercial power Alternating Current (AC) power supply supplies power for the three-bridge arm circuit, and the bidirectional direct current (DCDC) topology charges the battery pack. At this time, the bidirectional DCAC topology operates in an AC-DC mode (i.e., a full-bridge rectification PFC converter mode), the bidirectional DCDC topology operates in a BUCK mode (i.e., a step-down mode), and the BUS voltage output by the DC BUS capacitor E1 is stepped down to obtain a charging voltage of the battery pack, so that the battery pack is charged by using the charging voltage. At this time, the battery pack serves as an output source of the bidirectional DCDC topology. In this way, in the battery charging mode, the voltage conversion circuit and the three-arm circuit both participate in operation, that is, all devices of the three-arm topology device participate in operation.

In the battery power supply mode, the battery pack is an input source of the bidirectional DCDC topology, and the output of the bidirectional DCDC topology supplies power to the bidirectional DCAC topology. That is, the bidirectional DCDC topology discharges the battery pack. At this time, the bidirectional DCDC topology operates in a Boost mode (i.e., a Boost mode), the output voltage of the battery pack is boosted, and the boosted voltage is input to the dc bus capacitor E1 to maintain the bus voltage balance. The bidirectional DCAC topology works in a DC-AC mode (namely a full-bridge inverter mode), wherein a direct current bus capacitor E1 filters boosted direct current to obtain stable direct current, a second bridge arm and a third bridge arm of the three-bridge-arm circuit work in an inversion mode, and the stable direct current is converted into alternating current and then output to a load to supply power to the load. Meanwhile, the direct current bus capacitor E1 can store energy. By the mode, in the battery power supply mode, the voltage conversion circuit and the three-bridge-arm circuit are both involved in working, namely all devices of the three-bridge-arm topological device are involved in working.

With continued reference to fig. 63, the voltage conversion circuit according to the embodiment of the present application may include, for example: the device comprises a first voltage conversion unit, a transformer, an LC resonant cavity and a second voltage conversion unit. The first voltage conversion unit is connected with the low-voltage side of the transformer, and the high-voltage side of the transformer is connected with the LC resonant cavity and the second voltage conversion unit.

With continued reference to fig. 63, illustratively, the first voltage converting unit includes: a fourth bridge arm and a fifth bridge arm. The LC resonant cavity includes: a fifth inductance Lik and an inductance Cr. The second voltage conversion unit includes: and a sixth bridge arm. That is, the second voltage converting unit involved in this embodiment is a half-bridge topology.

It should be understood that the structure of the voltage conversion circuit involved in the present embodiment is the same as that of the voltage conversion circuit used in the three-bridge arm topology device shown in fig. 36. The description of the fourth leg, the fifth leg, and the LC resonant cavity can be referred to the description of this part in fig. 36, and will not be repeated. The difference is that in this embodiment, the fifth terminal of the voltage conversion circuit is connected to the midpoint of the first leg, whereas the fifth terminal of the voltage conversion circuit used in the three-leg topology apparatus shown in fig. 36 is connected to the midpoint of the second leg.

When the voltage conversion circuit shown in fig. 63 is used to charge the battery pack, the bidirectional DCDC topology operates in the full-bridge LLC resonant converter mode. At this time, the full-bridge LLC resonant converter can be controlled by adopting a full-bridge phase-shift control strategy, so that the leading arm in the full-bridge LLC resonant converter realizes zero-voltage turn-on, and the lagging arm in the full-bridge LLC resonant converter realizes zero-voltage turn-on and zero-current turn-off.

When the voltage conversion circuit shown in fig. 63 is used to discharge the battery pack, the bidirectional DCDC topology works in the full-bridge secondary-side LC resonant converter mode to achieve zero-voltage turn-on and zero-current turn-off, and specific working principles can be described in the prior art with respect to the full-bridge secondary-side LC resonant converter, which is not described again.

It should be understood that when the voltage conversion circuit is used for discharging the battery pack, the secondary side of the transformer TX1 connected to the LC resonant cavity is the high-voltage side of the voltage conversion circuit, and when the voltage conversion circuit is used for charging the battery pack, the secondary side of the transformer TX1 connected to the first voltage conversion unit is the low-voltage side of the voltage conversion circuit.

Alternatively, the high-voltage side of the transformer, the LC resonant cavity, the second voltage conversion unit, and the second bridge arm may also adopt a connection manner as shown in fig. 25 to fig. 31. The only difference is that when the connection method shown in fig. 25 to 31 is applied to the present embodiment, the first arm is used instead of the seventh arm in fig. 25 to 31. In these implementation manners, the end of the voltage conversion circuit connected to the midpoint of the first bridge arm is the fifth end of the voltage conversion circuit, which is not described again.

Fig. 63A is a schematic diagram ten of a partial connection of a voltage conversion circuit provided in the embodiment of the present application, and fig. 63B is a schematic diagram eleven of a partial connection of a voltage conversion circuit provided in the embodiment of the present application. Referring to fig. 63A and 63B, when the high-voltage side of the transformer, the LC resonant cavity, the second voltage conversion unit, and the second bridge arm adopt the connection manner shown in fig. 30 or 31, the first dotted terminal of the high-voltage side of the transformer is the third terminal of the voltage conversion circuit, and the second dotted terminal of the high-voltage side of the transformer is the fourth terminal of the voltage conversion circuit; the third end of the voltage conversion circuit is connected with the positive output end of the bus, and the fourth end of the voltage conversion circuit is connected with the negative output end of the bus; the voltage conversion circuit further comprises a fifth end, and the fifth end of the voltage conversion circuit is connected with the midpoint of the first bridge arm.

It should be understood that, when the voltage conversion circuit is implemented by using any of the above-described modified schemes, the mode of the bidirectional DCDC topology formed by the voltage conversion circuit, the first bridge arm, and the bus capacitor E1, which operates when the battery pack is charged, and the mode of the bidirectional DCDC topology formed by the voltage conversion circuit, the first bridge arm, and the bus capacitor E1, are the same as the mode of the voltage conversion circuit shown in fig. 63, and will not be described again.

The following takes the structure of the three-arm topology device shown in fig. 63 as an example, and schematically illustrates the states of the switches, the states of the switching tubes, and the current directions of the three-arm topology device in different power supply modes:

fig. 64 is a first current schematic diagram of a twentieth three-bridge-arm topology device in a battery-powered mode according to the embodiment of the present application. As shown in fig. 64, in the first phase of the battery power supply mode, i.e., in the positive half cycle of the output ac power, the second switching tube Q2, the eighth switching tube Q8, the ninth switching tube Q9 and the eleventh switching tube Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The positive pole of the battery pack → the ninth switching tube Q9 → the homonymous terminal of the low-voltage side of the TX1 → the synonym terminal of the low-voltage side of the TX1 → the eighth switching tube Q8 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The dotted terminal on the high-voltage side of the TX1 → the fifth inductor Lik → the eleventh switching tube Q11 → BUS + → BUS- → the second switching tube Q2 → the third capacitor Cr → the synonym terminal on the high-voltage side of the TX1 constitute an energy storage loop of the BUS capacitor E1. At this time, the transformer TX1 and the third capacitor Cr simultaneously supply energy to the bus capacitor E1.

Fig. 65 is a schematic current diagram of a twentieth three-bridge-arm topology device in a battery-powered mode according to the embodiment of the present application. As shown in fig. 65, in the second phase of the battery power supply mode, i.e., in the negative half cycle of the output ac power, the first switch Q1, the seventh switch Q7, the tenth switch Q10 and the twelfth switch Q12 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the seventh switching tube Q7 → the synonym end of the low-voltage side of TX1 → the synonym end of the low-voltage side of TX1 → the tenth switching tube Q10 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The unlike terminal on the high-voltage side of the TX1 → the third capacitor Cr → the first switching tube Q1 → BUS + → BUS- → the twelfth switching tube Q12 → the fifth inductor Lik → the like terminal on the high-voltage side of the TX1 constitute an energy storage loop of the BUS capacitor E1. At this time, the transformer TX1 and the third capacitor Cr simultaneously supply energy to the bus capacitor E1.

Fig. 66 is a first current schematic diagram of a twentieth three-bridge-arm topology device in a battery charging mode according to the embodiment of the present application. As shown in fig. 66, in the first phase of the battery charging mode, i.e., in the positive half-cycle of the input ac power, the second switch Q2 and the eleventh switch Q11 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. BUS + → eleventh switching tube Q11 → fifth inductance Lik → TX1 high-voltage side dotted terminal → TX1 high-voltage side synonym terminal → third capacitance Cr → second switching tube Q2 → BUS-, so that BUS capacitor E1 transmits energy for transformer TX1, and constitutes an energy storage loop of third capacitance Cr. The dotted terminal on the low-voltage side of TX1 → the ninth switching tube Q9 → the positive electrode of the battery pack → the negative electrode of the battery pack → the eighth switching tube Q8 → the dotted terminal on the low-voltage side of TX1, which constitutes the energy storage circuit of the battery pack. The ninth switching tube Q9 and the eighth switching tube Q8 are used for achieving a rectifying function.

Fig. 67 is a schematic current diagram of a twentieth three-bridge-arm topology device in a battery charging mode according to the embodiment of the present application. As shown in fig. 67, in the second phase of the battery charging mode, i.e. in the negative half-cycle of the input ac power, the first switch Q1 and the twelfth switch Q12 are controlled to be conductive. At this time, the current in the three-arm topology device flows as follows:

1. BUS + → the first switching tube Q1 → the third capacitor Cr → the different name end of the high voltage side of TX1 → the same name end of the high voltage side of TX1 → the fifth inductor Lik → the twelfth switching tube Q12 → BUS-, so that the BUS capacitor E1 transmits energy for the transformer TX1, and an energy storage loop of the third capacitor Cr is formed. The synonym end of the low-voltage side of TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the synonym end of the low-voltage side of TX1 constitutes an energy storage loop of the battery pack. The seventh switching tube Q7 and the tenth switching tube Q10 are used for achieving a rectification function.

Structure B23: the voltage conversion circuit in the three-bridge arm topology device realizes a voltage conversion function by multiplexing a second bridge arm of the three-bridge arm circuit and the bus capacitor E1. The three-bridge-arm topological device can be applied to a battery low-voltage large-current inverter system.

Fig. 68 is a schematic diagram of a twenty-first three-bridge-arm topology device according to an embodiment of the present application. As shown in fig. 68, in this embodiment, the first terminal of the first capacitor Co is the first external connection terminal of the three-arm topology device, and the second terminal of the first capacitor Co is the second external connection terminal of the three-arm topology device.

Taking the external power supply as a commercial AC power supply as an example, the commercial AC power supply AC and the load are connected to the first end of the first capacitor Co and the second end of the first capacitor Co through a relay, respectively. When discharging the battery pack, the relay conducts a path between the load and the first capacitor Co. When the battery pack is charged, the relay conducts a path between the commercial power alternating current power supply AC and the first capacitor Co.

For convenience of description, the figure is denoted AC. It should be understood that when discharging the battery pack, AC herein characterizes the alternating current output by the three-arm topology. When charging the battery pack, AC herein characterizes the mains alternating current supply AC that supplies power to the three-arm topology.

The positive pole of the battery pack is connected with the first end of the voltage conversion circuit, and the negative pole of the battery pack is connected with the second end of the voltage conversion circuit. And the third end of the voltage conversion circuit is connected with the midpoint of the first bridge arm, and the fourth end of the voltage conversion circuit is connected with the midpoint of the second bridge arm.

In the present embodiment, the voltage conversion circuit, the first arm and the second arm of the three-arm circuit, and the bus capacitor E1 form a bidirectional DCDC topology (may also be referred to as a bidirectional DCDC converter) to realize a bidirectional voltage conversion function. The bus capacitor E1, the second arm, the third arm, and the LC filter of the three-arm circuit form a bidirectional DCAC topology (which may also be referred to as a bidirectional DCAC converter). That is, the bidirectional DCDC topology and the bidirectional DCAC topology multiplex the second leg and the bus capacitance E1.

In a battery charging mode, a commercial power alternating current power supply AC supplies power to the three-bridge arm circuit, the bidirectional DCAC topology works in an AC-DC mode (namely a full-bridge rectification PFC converter mode), the bidirectional DCDC topology works in a BUCK mode (namely a voltage reduction mode), and the BUS voltage output by the direct current BUS capacitor E1 is subjected to voltage reduction processing to obtain the charging voltage of the battery pack, so that the battery pack is charged by using the charging voltage. At this time, the battery pack serves as an output source of the bidirectional DCDC topology. In this way, in the battery charging mode, the voltage conversion circuit and the three-arm circuit both participate in operation, that is, all devices of the three-arm topology device participate in operation.

In the battery power supply mode, the battery pack is an input source of the bidirectional DCDC topology, and the output of the bidirectional DCDC topology supplies power for the three-bridge-arm circuit. That is, the bidirectional DCDC topology discharges the battery pack. At this time, the bidirectional DCDC topology operates in a Boost mode (i.e., a Boost mode), the output voltage of the battery pack is boosted, and the boosted voltage is input to the dc bus capacitor E1 to maintain the bus voltage balance. The bidirectional DCAC topology works in a DC-AC mode (namely a full-bridge inverter mode), the direct current bus capacitor E1 filters the boosted direct current to obtain stable direct current, the second bridge arm and the third bridge arm work in an inverter mode, and the stable direct current is converted into alternating current and then output to a load to supply power to the load. Meanwhile, the direct current bus capacitor E1 can store energy. By the mode, in the battery power supply mode, the voltage conversion circuit and the three-bridge-arm circuit are both involved in working, namely all devices of the three-bridge-arm topological device are involved in working.

With continued reference to the conventional battery low-voltage large-current inverter system shown in fig. 1A, the conventional battery low-voltage large-current inverter system has the following problems, in addition to the problems of low integration level and low device reuse rate:

The first point is that: the switching device of the Buck converter is connected in series in a main power loop of the battery low-voltage large-current inverter system, so that the conduction loss and the heat cost of the existing battery low-voltage large-current inverter system are increased, and the reliability is reduced.

And a second point: under the battery charging mode, multiple voltage regulation (namely, alternating current provided by a commercial power alternating current power supply AC is firstly boosted by a full-bridge rectification PFC converter and then is provided for a bidirectional DCDC converter after being reduced by a Buck converter), the system complexity of the battery low-voltage large-current inverter system is increased, and the system efficiency is reduced.

Compared with the battery low-voltage large-current inverter system with the three-stage converter provided in fig. 1A, in the embodiment of the present application, when the three-arm topology apparatus provided in fig. 63 and 68 is applied to the battery voltage large-current inverter system, the battery low-voltage large-current inverter system is modified from the three-stage converter topology to the two-stage converter topology through the bidirectional DCDC topology and the bidirectional DCAC topology.

Under the topological structure of the secondary converter, no matter in a battery power supply mode or a battery charging mode, all devices of the three-bridge arm topological device participate in working, the integration level of the battery low-voltage high-current inverter system is improved, the reuse rate of the devices is improved, the material cost of the system is reduced, the conduction loss and the heat cost of the existing battery low-voltage high-current inverter system are reduced, and the reliability is improved.

In addition, after the battery low-voltage large-current inverter system is modified from a three-stage converter topology to a two-stage converter topology, a power conversion path is shorter, and the system efficiency is improved.

Fig. 69 is a schematic diagram of a twenty-second three-bridge arm topology device according to an embodiment of the present application. As shown in fig. 69, when the three-arm topology device shown in fig. 68 is applied to a unidirectional battery low-voltage high-current inverter system (i.e., the system only supports supplying power to a load, and charging of a battery pack needs to be implemented by means of an external charger), the first switching tube and the second switching tube included in the first arm of the three-arm topology device shown in fig. 68 may be replaced by two diodes, for example, the structure of the three-arm topology device shown in fig. 69. Under this structure, the principle of the three-bridge arm topology device for supplying power to the load is similar to that of the three-bridge arm topology device shown in fig. 68, and the description thereof is omitted.

The voltage conversion circuit according to the embodiment of the present application may be a voltage conversion circuit having electrical isolation, or may be a voltage conversion circuit without electrical isolation.

With continued reference to fig. 68, the voltage conversion circuit according to the embodiment of the present application may include, for example: the first voltage conversion unit, transformer, LC resonant cavity. The first voltage conversion unit is connected with the low-voltage side of the transformer, and the high-voltage side of the transformer is connected with the LC resonant cavity.

With continued reference to fig. 68, illustratively, the first voltage converting unit includes: a fourth bridge arm and a fifth bridge arm. The LC resonant cavity includes: a fifth inductance Lik and an inductance Cr.

Wherein the fourth leg comprises: a seventh switch tube Q7 and an eighth switch tube Q8 connected in series (i.e., the first end of the seventh switch tube Q7 is connected to the first end of the eighth switch tube Q8); the fifth arm includes: a ninth switching tube Q9 and a tenth switching tube Q10 connected in series (i.e., the first end of the ninth switching tube Q9 is connected to the first end of the tenth switching tube Q10). The fourth leg is connected in parallel with the fifth leg (i.e., the second end of the seventh switching tube Q7 is connected to the second end of the ninth switching tube Q9, and the second end of the eighth switching tube Q8 is connected to the second end of the tenth switching tube Q10).

For the description of the fourth leg, the fifth leg and the LC resonant cavity, reference may be made to the description of the fourth leg, the fifth leg and the LC resonant cavity in fig. 3, and details are not repeated here. In some embodiments, the first voltage conversion unit shown in fig. 68 may also be referred to as a full-bridge conversion circuit.

The second terminal of the seventh switch Q7 is the first terminal of the voltage converting circuit, and the second terminal of the eighth switch Q8 is the second terminal of the voltage converting circuit.

The midpoint of the fourth bridge arm is connected with the different-name end of the low-voltage side of the transformer TX1, and the midpoint of the fifth bridge arm is connected with the same-name end of the low-voltage side of the transformer TX 1. The dotted end of the high-voltage side of the transformer is connected with the first end of a fifth inductor Lik, the second end of the fifth inductor Lik is connected with the midpoint of the first bridge arm, the dotted end of the high-voltage side of the transformer is connected with the first end of a third capacitor Cr, and the second end of the third capacitor Cr is connected with the midpoint of the second bridge arm. That is, the second terminal of the fifth inductor Lik is the third terminal of the voltage conversion circuit, and the second terminal of the third capacitor Cr is the fourth terminal of the voltage conversion circuit.

When the voltage conversion circuit is used for charging the battery pack, the bidirectional DCDC topology works in a half-bridge LLC resonant converter mode, and therefore voltage regulation in a wide range is achieved, and zero-voltage switching-on is achieved. When the voltage conversion circuit is adopted to discharge the battery pack, the bidirectional DCDC topology works in a full-bridge secondary LC resonance voltage-multiplying converter mode, the purpose of twice boosting is achieved, and the boosting ratio of the bidirectional DCDC topology is improved.

Alternatively, the high-voltage side of the transformer and the LC resonant cavity, the first arm and the second arm may also be connected as shown in fig. 25 to fig. 31. The only difference is that when the connection method shown in fig. 25 to 31 is applied to this embodiment, the first arm is used instead of the sixth arm in fig. 25 to 31, and the second arm is used instead of the seventh arm in fig. 25 to 31. In these implementation manners, the end of the voltage conversion circuit connected to the midpoint of the first bridge arm is a third end of the voltage conversion circuit, and the end of the voltage conversion circuit connected to the midpoint of the second bridge arm is a fourth end of the voltage conversion circuit, which is not described again.

Fig. 68A is a twelfth partial connection schematic diagram of the voltage conversion circuit provided in the embodiment of the present application, and fig. 68B is a thirteenth partial connection schematic diagram of the voltage conversion circuit provided in the embodiment of the present application. Referring to fig. 68A, when the high-voltage side of the transformer and the LC resonant cavity, the first bridge arm, and the second bridge arm are connected in the manner shown in fig. 30, the second end of the first switching tube is connected to the first different name end of the high-voltage side of the transformer, and the second end of the second switching tube is connected to the second different name end of the high-voltage side of the transformer; the first dotted end of the high-voltage side of the transformer is connected with the positive output end of the bus, and the second dotted end of the high-voltage side of the transformer is connected with the negative output end of the bus; the first end of the fifth inductor is a third end of the voltage conversion circuit, the second end of the fifth inductor is connected with the first end of the third capacitor, and the second end of the third capacitor is a fourth end of the voltage conversion circuit.

Referring to fig. 68B, when the high-voltage side of the transformer and the LC resonant cavity, the first bridge arm, and the second bridge arm are connected in the manner shown in fig. 31, the second end of the first switching tube is connected to the first different name end of the high-voltage side of the transformer, and the second end of the second switching tube is connected to the second different name end of the high-voltage side of the transformer; the first dotted terminal of the high-voltage side of the transformer is connected with the positive output end of the bus, and the second dotted terminal of the high-voltage side of the transformer is connected with the negative output end of the bus; the first end of the third capacitor is the third end of the voltage conversion circuit, the second end of the third capacitor is connected with the first end of the fifth inductor, and the second end of the fifth inductor is the fourth end of the voltage conversion circuit.

It should be understood that, when the voltage conversion circuit is implemented by using any of the above-described modified schemes, the "bidirectional DCDC topology formed by the voltage conversion circuit, the first leg, the second leg, and the bus capacitor E1" is the same as the voltage conversion circuit shown in fig. 68, and thus the description thereof is omitted.

The following takes the structure of the three-arm topology device shown in fig. 68 as an example, and schematically illustrates the states of the switches, the states of the switching tubes, and the current directions of the three-arm topology device in different power supply modes:

fig. 70 is a first schematic current diagram of a twenty-first three-bridge-arm topology device in a battery-powered mode according to an embodiment of the present application. As shown in fig. 70, in the first phase of the battery power supply mode, that is, in the first phase of the positive half cycle of the output ac power, the second switching tube Q2, the fourth switching tube Q4, the fifth switching tube Q5, the seventh switching tube Q7 and the tenth switching tube Q10 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the seventh switching tube Q7 → the synonym end of the low-voltage side of TX1 → the synonym end of the low-voltage side of TX1 → the tenth switching tube Q10 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The synonym terminal of the high-voltage side of TX1 → the third capacitor Cr → the fourth switching tube Q4 → the second switching tube Q2 → the fifth inductor Lik → the synonym terminal of the high-voltage side of TX1 constitute an energy storage loop of the third capacitor Cr.

Fig. 71 is a schematic current diagram of a twenty-first three-bridge-arm topology device in a battery-powered mode according to an embodiment of the present application. As shown in fig. 71, in the second phase of the battery power mode, that is, in the second phase of the positive half cycle of the output ac power, the first switching tube Q1, the fourth switching tube Q4, the fifth switching tube Q5, the eighth switching tube Q8 and the ninth switching tube Q9 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the ninth switching tube Q9 → the homonymous terminal of the low-voltage side of the TX1 → the synonym terminal of the low-voltage side of the TX1 → the eighth switching tube Q8 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The dotted terminal on the high-voltage side of TX1 → the fifth inductor Lik → the first switching tube Q1 → BUS + → BUS- → the fourth switching tube Q4 → the third capacitor Cr → the dotted terminal on the high-voltage side of TX1 form an energy storage loop of the BUS capacitor E1. At this time, the transformer TX1 and the third capacitor Cr simultaneously supply energy to the bus capacitor E1.

Fig. 72 is a current schematic diagram third of a twenty-first three-bridge topology device in a battery power supply mode according to the embodiment of the present application. As shown in fig. 72, in the third phase of the battery power supply mode, that is, in the third phase of the positive half cycle of the output ac power, the second switching tube Q2, the fourth switching tube Q4, the sixth switching tube Q6, the seventh switching tube Q7 and the tenth switching tube Q10 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the seventh switching tube Q7 → the different name end of the low-voltage side of the TX1 → the same name end of the low-voltage side of the TX1 → the tenth switching tube Q10 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The synonym terminal of the high-voltage side of TX1 → the third capacitor Cr → the fourth switching tube Q4 → the second switching tube Q2 → the fifth inductor Lik → the synonym terminal of the high-voltage side of TX1 constitute an energy storage loop of the third capacitor Cr.

Fig. 73 is a current schematic diagram of a twenty-first three-bridge topology device in a battery power supply mode according to an embodiment of the present application. As shown in fig. 73, in the fourth phase of the battery power supply mode, that is, in the fourth phase of the positive half cycle of the output ac power, the first switching tube Q1, the fourth switching tube Q4, the sixth switching tube Q6, the eighth switching tube Q8 and the ninth switching tube Q9 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The positive pole of the battery pack → the ninth switching tube Q9 → the dotted terminal on the low-voltage side of TX1 → the different-dotted terminal on the low-voltage side of TX1 → the eighth switching tube Q8 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The dotted terminal on the high-voltage side of the TX1 → the fifth inductor Lik → the first switching tube Q1 → BUS + → BUS- → the fourth switching tube Q4 → the third capacitor Cr → the dotted terminal on the high-voltage side of the TX1 constitute an energy storage loop of the BUS capacitor E1. At this time, the transformer TX1 and the third capacitor Cr simultaneously supply energy to the bus capacitor E1.

Fig. 74 is a fifth current schematic diagram of a twenty-first three-bridge-arm topology device in a battery power supply mode according to an embodiment of the present application. As shown in fig. 74, in the fifth phase of the battery power supply mode, i.e., in the first phase of the negative half cycle of the output alternating current, the first switch tube Q1, the third switch tube Q3, the sixth switch tube Q6, the eighth switch tube Q8 and the ninth switch tube Q9 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The positive pole of the battery pack → the ninth switching tube Q9 → the homonymous terminal of the low-voltage side of the TX1 → the synonym terminal of the low-voltage side of the TX1 → the eighth switching tube Q8 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The dotted terminal on the high-voltage side of the TX1 → the fifth inductor Lik → the first switching tube Q1 → the third switching tube Q3 → the third capacitor Cr → the dotted terminal on the high-voltage side of the TX1, which constitutes the energy storage loop of the third capacitor Cr.

Fig. 75 is a current schematic diagram six of a twenty-first three-bridge topology device in a battery power supply mode according to the embodiment of the present application. As shown in fig. 75, in the sixth phase of the battery power supply mode, that is, in the second phase of the negative half cycle of the output alternating current, the first switching tube Q1, the second switching tube Q2, the third switching tube Q3, the sixth switching tube Q6, the seventh switching tube Q7 and the tenth switching tube Q10 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the seventh switching tube Q7 → the synonym end of the low-voltage side of TX1 → the synonym end of the low-voltage side of TX1 → the tenth switching tube Q10 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The unlike terminal on the high-voltage side of the TX1 → the third capacitor Cr → the first switching tube Q1 → BUS + → BUS- → the second switching tube Q2 → the fifth inductor Lik → the like terminal on the high-voltage side of the TX1, and an energy storage loop of the BUS capacitor E1 is formed. At this time, the transformer TX1 and the third capacitor Cr simultaneously supply energy to the bus capacitor E1.

Fig. 76 is a seventh current schematic diagram of a twenty-first three-bridge-arm topology device in a battery-powered mode according to an embodiment of the present application. As shown in fig. 76, in the seventh phase of the battery power supply mode, i.e., in the third phase of the negative half cycle of the output ac power, the first switch tube Q1, the third switch tube Q3, the fifth switch tube Q5, the eighth switch tube Q8 and the ninth switch tube Q9 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

Fig. 77 is a schematic current diagram eight of a twenty-first three-bridge-arm topology device in a battery power supply mode according to the embodiment of the present application. As shown in fig. 77, in the eighth phase of the battery power supply mode, that is, in the fourth phase of the negative half cycle of the output alternating current, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fifth switch tube Q5, the seventh switch tube Q7 and the tenth switch tube Q10 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the positive pole of the battery pack → the seventh switching tube Q7 → the different name end of the low-voltage side of the TX1 → the same name end of the low-voltage side of the TX1 → the tenth switching tube Q10 → the negative pole of the battery pack, so that the battery pack transmits energy to the transformer TX 1. The unlike terminal on the high-voltage side of the TX1 → the third capacitor Cr → the first switching tube Q1 → BUS + → BUS- → the second switching tube Q2 → the fifth inductor Lik → the like terminal on the high-voltage side of the TX1, and an energy storage loop of the BUS capacitor E1 is formed. At this time, the transformer TX1 and the third capacitor Cr simultaneously supply energy to the bus capacitor E1.

Fig. 78 is a first schematic current diagram of a twenty-first three-bridge topology device in a battery charging mode according to an embodiment of the present disclosure. As shown in fig. 78, in the first phase of the battery charging mode, i.e. in the first phase of the positive half-cycle of the input ac power, the first switching tube Q1, the fourth switching tube Q4 and the sixth switching tube Q6 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the live wire of the commercial power alternating-current power supply AC → the second inductor L2 → the sixth switching tube Q6 → the fourth switching tube Q4 → the zero wire of the commercial power alternating-current power supply AC, and the energy storage loop of the second inductor L2 is formed.

2. BUS + → first switch tube Q1 → fifth inductance Lik → TX1 high-voltage side dotted terminal → TX1 high-voltage side dotted terminal → third capacitor Cr → fourth switch tube Q4 → BUS-, so that BUS capacitor E1 transmits energy for transformer TX1, and constitutes an energy storage loop of third capacitor Cr.

The dotted terminal on the low-voltage side of TX1 → the ninth switching tube Q9 → the positive electrode of the battery pack → the negative electrode of the battery pack → the eighth switching tube Q8 → the dotted terminal on the low-voltage side of TX1, which constitutes the energy storage circuit of the battery pack. The ninth switching tube Q9 and the eighth switching tube Q8 are used for achieving a rectifying function.

Fig. 79 is a schematic current diagram of a twenty-first three-bridge topology device in a battery charging mode according to an embodiment of the present application. As shown in fig. 79, in the second phase of the battery charging mode, i.e., in the second phase of the positive half cycle of the input ac power, the second switching tube Q2, the fourth switching tube Q4 and the sixth switching tube Q6 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. The Cr positive pole → the synonym terminal at the high-voltage side of TX1 → the synonym terminal at the high-voltage side of TX1 → the fifth inductor Lik → the second switching tube Q2 → the fourth switching tube Q4 → the Cr negative pole, so that the Cr transmits energy for the transformer TX 1. The synonym end of the low-voltage side of TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the synonym end of the low-voltage side of TX1 constitutes an energy storage loop of the battery pack. The seventh switch tube Q7 and the tenth switch tube Q10 are used for realizing a rectification function.

Fig. 80 is a current schematic diagram of a twenty-first three-bridge topology device in a battery charging mode according to the embodiment of the present application. As shown in fig. 80, in the third phase of the battery charging mode, i.e., in the third phase of the positive half-cycle of the input ac power, the first switch transistor Q1, the fourth switch transistor Q4 and the fifth switch transistor Q5 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the live wire of the mains supply alternating-current power supply AC → the second inductor L2 → the fifth switching tube Q5 → BUS + → BUS- → the fourth switching tube Q4 → the zero line of the mains supply alternating-current power supply AC, and an energy storage loop is formed, wherein the second inductor L2 and the mains supply simultaneously store energy for the direct-current BUS capacitor E1.

Fig. 81 is a fourth current schematic diagram of a twenty-first three-bridge topology device in a battery charging mode according to the embodiment of the present application. As shown in fig. 81, in the fourth phase of the battery charging mode, i.e., in the fourth phase of the positive half cycle of the input ac power, the second switching tube Q2, the fourth switching tube Q4 and the fifth switching tube Q5 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. The Cr positive pole → the synonym terminal at the high-voltage side of TX1 → the synonym terminal at the high-voltage side of TX1 → the fifth inductor Lik → the second switching tube Q2 → the fourth switching tube Q4 → the Cr negative pole, so that the Cr transmits energy for the transformer TX 1. The different name end on the low-voltage side of the TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the same name end on the low-voltage side of the TX1, and a storage circuit of the battery pack is formed. The seventh switch tube Q7 and the tenth switch tube Q10 are used for realizing a rectification function.

Fig. 82 is a fifth current schematic diagram of a twenty-first three-bridge topology device in a battery charging mode according to an embodiment of the present application. As shown in fig. 82, in the fifth phase of the battery charging mode, i.e., in the first phase of the negative half cycle of the input ac power, the second switching tube Q2, the third switching tube Q3 and the fifth switching tube Q5 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. the neutral line of the commercial power alternating-current power supply AC → the third switching tube Q3 → the fifth switching tube Q5 → the second inductor L2 → the live wire of the commercial power alternating-current power supply AC constitute an energy storage loop of the second inductor L2.

2. BUS + → third switching tube Q3 → third capacitor Cr → synonym terminal of TX1 high-voltage side → synonym terminal of TX1 high-voltage side → fifth inductor Lik → second switching tube Q2 → BUS-, so that BUS capacitor E1 transmits energy for transformer TX1, and an energy storage loop of third capacitor Cr is formed. The synonym end of the low-voltage side of TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the synonym end of the low-voltage side of TX1 constitutes an energy storage loop of the battery pack. The seventh switching tube Q7 and the tenth switching tube Q10 are used for achieving a rectification function.

Fig. 83 is a sixth schematic current diagram of a twenty-first three-bridge topology device in a battery charging mode according to an embodiment of the present application. As shown in fig. 83, in the sixth phase of the battery charging mode, i.e., in the second phase of the negative half cycle of the input ac power, the first switch tube Q1, the third switch tube Q3 and the fifth switch tube Q5 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. The Cr positive pole → the third switching tube Q3 → the first switching tube Q1 → the fifth inductor Lik → the dotted terminal on the high-voltage side of TX1 → the different terminal on the high-voltage side of TX1 → the Cr negative pole, so that the Cr transmits energy to the transformer TX 1.

Fig. 84 is a seventh schematic current diagram of a twenty-first three-bridge topology device in a battery charging mode according to an embodiment of the present application. As shown in fig. 84, in the seventh phase of the battery charging mode, i.e., in the third phase of the negative half cycle of the input ac power, the second switching tube Q2, the third switching tube Q3 and the sixth switching tube Q6 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

1. The zero line of the commercial power alternating-current power supply AC → the third switching tube Q3 → BUS + → BUS- → the sixth switching tube Q6 → the second inductor L2 → the live wire of the commercial power alternating-current power supply AC, and an energy storage loop is formed, wherein the second inductor L2 and the commercial power simultaneously store energy for the direct-current BUS capacitor E1.

2. BUS + → third switching tube Q3 → third capacitor Cr → synonym terminal of TX1 high-voltage side → synonym terminal of TX1 high-voltage side → fifth inductor Lik → second switching tube Q2 → BUS-, so that BUS capacitor E1 transmits energy for transformer TX1, and an energy storage loop of third capacitor Cr is formed. The synonym end of the low-voltage side of TX1 → the seventh switch tube Q7 → the positive pole of the battery pack → the negative pole of the battery pack → the tenth switch tube Q10 → the synonym end of the low-voltage side of TX1 constitutes an energy storage loop of the battery pack. The seventh switch tube Q7 and the tenth switch tube Q10 are used for realizing a rectification function.

Fig. 85 is a current schematic diagram eight of a twenty-first three-bridge topology device in a battery charging mode according to an embodiment of the present application. As shown in fig. 85, in the eighth phase of the battery charging mode, that is, in the fourth phase of the negative half-cycle of the input alternating current, the first switching tube Q1, the third switching tube Q3 and the sixth switching tube Q6 are controlled to be turned on. At this time, the current in the three-arm topology device flows as follows:

2. The positive pole of Cr → the third switching tube Q3 → the first switching tube Q1 → the fifth inductor Lik → the dotted terminal on the high-voltage side of TX1 → the synonym terminal on the high-voltage side of TX1 → the negative pole of Cr, so that Cr transmits energy to the transformer TX 1.

The dotted terminal on the low-voltage side of TX1 → the ninth switching tube Q9 → the positive electrode of the battery pack → the negative electrode of the battery pack → the eighth switching tube Q8 → the dotted terminal on the low-voltage side of TX1, which forms a storage circuit of the battery pack. The ninth switching tube Q9 and the eighth switching tube Q8 are used for achieving a rectification function.

In the three-arm topology device (the three-arm topology device shown in fig. 63 to 85) applied to the battery low-voltage large-current inverter system, the connection relationship between the LC filter and the second and third arms may be as follows:

fig. 86 is a schematic diagram of a connection relationship between an LC filter and the second and third bridge arms according to an embodiment of the present application. As shown in fig. 86, the midpoint of the second leg is connected to the first end of the second inductor L2, the second end of the second inductor L2 is connected to the second end of the first capacitor Co, and the first end of the first capacitor Co is connected to the midpoint of the third leg. The first end of the first capacitor Co is a first external connection end of the three-bridge-arm topology device, and the second end of the first capacitor Co is a second external connection end of the three-bridge-arm topology device.

In some implementations, the LC filter applied to the three-arm topology device (the three-arm topology device shown in fig. 63 to 85) of the battery low-voltage high-current inverter system may be replaced by an LCL filter (i.e., a filter composed of two inductors and one capacitor).

Fig. 87 is a schematic diagram of a connection relationship between an LCL filter and the second and third bridge arms according to an embodiment of the present disclosure. Taking the LCL filter including "the second inductor L2, the first capacitor Co, and the fourth inductor L4" as an example, the connection relationship may be as follows:

the midpoint of the third leg is connected to the first end of the second inductor L2, the second end of the second inductor L2 is connected to the first end of the first capacitor Co, the second end of the first capacitor Co is connected to the first end of the fourth inductor L4, and the second end of the fourth inductor L4 is connected to the midpoint of the second leg. The first end of the first capacitor Co is a first external connection end of the three-bridge-arm topology device, and the second end of the first capacitor Co is a second external connection end of the three-bridge-arm topology device.

It should be understood that, although the three-bridge arm topology apparatus described above is exemplified by being applied to a battery low-voltage large-current UPS system or a battery low-voltage large-current inverter system, those skilled in the art can understand that, for the three-bridge arm topology apparatus applied to the battery low-voltage large-current UPS system, the three-bridge arm topology apparatus may also be applied to other UPS systems (e.g., a high-power UPS system), or other systems (e.g., an inverter system) that use different power sources (mains supply or battery packs) to supply power under different conditions, and the details are not described herein again. For a three-bridge arm topology device applied to a battery low-voltage large-current inverter system, the three-bridge arm topology device can also be applied to other inverter systems (such as a high-power UPS system) and the like, and details are not repeated here.

It is to be understood that various numbers (for example, the first switch tube, the second switch tube, the first switch, the second switch, etc.) referred to in the embodiments of the present application are only for convenience of description and are not used to limit the scope of the embodiments of the present application.

It is understood that each of the switching tubes according to the embodiments of the present application may be any switching tube capable of being turned on or off based on control, for example, an Insulated Gate Bipolar Transistor (IGBT), a Metal Oxide Semiconductor field effect Transistor (MOS), a triode, or a thyristor. The switching tubes used in different circuits may be different or the same, for example, the switching tube in the voltage conversion circuit uses an MOS tube, the switching tube in the three-bridge arm circuit uses an IGBT, or the switching tubes in the voltage conversion circuit and the three-bridge arm circuit are both IGBTs. In addition, the same switching tube may be used in the same circuit, or different switching tubes may be used, which is not limited to this.

In addition, although the foregoing embodiments schematically illustrate the states of the switching tubes and the current directions of the three-arm topology devices with various structures in different power supply modes according to the embodiments of the present application. However, it can be understood by those skilled in the art that, for the switching tube not mentioned in the above description, in an external power supply mode or a battery power supply mode of the three-arm topology device, the switching tube may be in an off state, or rectification is achieved by an external diode of the switching tube, or rectification is achieved by body conduction of the switching tube, which may be determined according to a control manner. That is to say, the control method of each switching tube in the three-bridge arm topology device provided in the embodiment of the present application includes, but is not limited to, the method listed in the above embodiment, and may also be implemented in other ways, which is not limited in the embodiment of the present application.

On the other hand, an embodiment of the present application further provides an uninterruptible power supply system, where the system includes: an external power supply, a load, and, a three-bridge arm topology device as shown in the foregoing embodiments (e.g., a three-bridge arm topology device as shown in any one of fig. 2, 4 to 7, and 14 to 23, 24 to 61). The first end of the external power supply is connected with the positive voltage input end AC _ L of the three-bridge arm topology device, the second end of the external power supply is connected with the negative voltage input end AC _ N of the three-bridge arm topology device, and the first output end and the second output end of the three-bridge arm topology device are connected with the load. The external power supply referred to herein may be, for example, a mains AC power supply or a photovoltaic PV dc power supply.

In another aspect, an embodiment of the present application further provides an uninterruptible power supply system, where the uninterruptible power supply system includes: a first external power supply, a second external power supply, a load, and a three-bridge arm topology device shown in the foregoing embodiments (e.g., the three-bridge arm topology device illustrated in fig. 62). The first end of the first external power supply source is connected with a first positive voltage input end of the three-bridge-arm topological device, the second end of the first external power supply source is connected with a first negative voltage input end of the three-bridge-arm topological device, the first end of the second external power supply source is connected with a second positive voltage input end of the three-bridge-arm topological device, the second end of the second external power supply source is connected with a second negative voltage input end of the three-bridge-arm topological device, and a first output end and a second output end of the three-bridge-arm topological device are both connected with a load.

The first external power supply and the second external power supply referred to herein may be two different power supplies. For example, the first external power source may be, for example, a mains AC power source and the second external power source may be, for example, a photovoltaic PV dc power source. In this example, the live wire of the AC mains supply is connected to the first positive voltage input AC _ L of the three-arm topology device, the zero line of the AC mains supply is connected to the first negative voltage input AC _ N of the three-arm topology device, the positive pole of the PV dc power supply is connected to the second positive voltage input PV + of the three-arm topology device, and the negative pole of the PV dc power supply is connected to the second negative voltage input PV-of the three-arm topology device.

Alternatively, the first external power supply may be, for example, a photovoltaic PV dc power supply and the second external power supply may be, for example, a mains AC power supply. In this example, a live wire of the commercial AC power supply AC is connected to the second positive voltage input terminal AC _ L of the three-arm topology device, a zero line of the commercial AC power supply AC is connected to the second negative voltage input terminal AC _ N of the three-arm topology device, a positive electrode of the photovoltaic PV dc power supply is connected to the first positive voltage input terminal PV + of the three-arm topology device, and a negative electrode of the photovoltaic PV dc power supply is connected to the first negative voltage input terminal PV-of the three-arm topology device.

The uninterruptible power supply system provided by the embodiment of the application can be a battery low-voltage large-current UPS system or an online medium-small power UPS system and the like.

The UPS system provided in the embodiment of the present application has the similar implementation principle and technical effect to the aforementioned three-bridge-arm topology device applied to the battery low-voltage large-current UPS system, and is not described herein again.

In another aspect, an embodiment of the present application further provides an inverter system, which includes: a load, and a three-arm topology as shown in the previous embodiments (e.g., a three-arm topology as shown in any of fig. 63-68, 70-85).

In a battery powered mode, the first external connection end and the second external connection end of the three-arm topology device are both connected to the load.

Optionally, the inverter system may further include: an external power supply; and when the battery is in a charging mode, the first external connecting end and the second external connecting end of the three-bridge-arm topological device are both connected with the external power supply.

The inverter system provided by the embodiment of the application can be a battery low-voltage large-current inverter system or an online medium-low power inverter system. The inverter system provided by the embodiment of the application has the implementation principle and the technical effect similar to those of the three-bridge-arm topology device applied to the battery low-voltage large-current inverter system, and is not repeated herein.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the embodiments of the present application, and are not limited thereto; although the embodiments of the present application have been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

A three-leg topology device, comprising: the device comprises a battery pack, a voltage conversion circuit and a three-bridge circuit;

the three-bridge arm circuit includes: the bridge comprises a first bridge arm, a second bridge arm, a third bridge arm, a first inductor, a second inductor, a direct current bus capacitor and a first capacitor;

the first bridge arm comprises a first switching tube and a second switching tube which are connected in series;

the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series;

the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series;

the first bridge arm, the second bridge arm, the third bridge arm and the direct current bus capacitor are connected in parallel between a positive output end and a negative output end of a bus; the midpoint of the first bridge arm is connected with the first end of the first inductor, and the second end of the first inductor is used as a positive voltage input end of the three-bridge-arm topology device; the midpoint of the second bridge arm or the negative output end of the bus is used as a negative voltage input end of the three-bridge-arm topological device; the middle point of the third bridge arm is connected with the first end of the second inductor, the second end of the second inductor is connected with the first end of the first capacitor, the second end of the first capacitor is connected with the middle point of the second bridge arm, the first end of the first capacitor is a first output end of the three-bridge-arm topological device, the second end of the first capacitor is a second output end of the three-bridge-arm topological device, and the first output end and the second output end are both connected with a load;

The positive electrode of the battery pack is connected with the first end of the voltage conversion circuit, the negative electrode of the battery pack is connected with the second end of the voltage conversion circuit, the third end of the voltage conversion circuit is connected with the positive output end of the bus, the fourth end of the voltage conversion circuit is connected with the negative output end of the bus, the first end of an external power supply is connected with the positive voltage input end, and the second end of the external power supply is connected with the negative voltage input end;

the voltage conversion circuit is used for charging the battery pack in an external power supply mode; discharging the battery pack in a battery powered mode.
The apparatus of claim 1, wherein the voltage conversion circuit comprises: the device comprises a first voltage conversion unit, a second voltage conversion unit, a transformer and an LC resonant cavity; the LC resonant cavity comprises: a fifth inductor and a third capacitor;

the first voltage conversion unit is connected with the low-voltage side of the transformer, and the high-voltage side of the transformer is connected with the resonant cavity and the second voltage conversion unit.
The apparatus of claim 2, wherein the first voltage conversion unit comprises: a fourth bridge arm and a fifth bridge arm; the fourth leg includes: a seventh switching tube and an eighth switching tube; the fifth bridge arm comprises a ninth switching tube and a tenth switching tube;

A first end of the seventh switching tube is connected with a first end of the eighth switching tube, a first end of the ninth switching tube is connected with a first end of the tenth switching tube, a second end of the seventh switching tube is connected with a second end of the ninth switching tube, and a second end of the eighth switching tube is connected with a second end of the tenth switching tube;

the midpoint of the fourth bridge arm is connected with the synonym end of the low-voltage side of the transformer, and the midpoint of the fifth bridge arm is connected with the synonym end of the low-voltage side of the transformer;

the second end of the seventh switching tube is the first end of the voltage conversion circuit, and the second end of the eighth switching tube is the second end of the voltage conversion circuit.
The apparatus of claim 2, wherein the first voltage conversion unit comprises: a seventh switching tube and an eighth switching tube;

a first end of the seventh switching tube is connected with a first homonymous end on the low-voltage side of the transformer, a first end of the eighth switching tube is connected with a heteronymous end on the low-voltage side of the transformer, and a second end of the seventh switching tube is connected with a second end of the eighth switching tube;

and the second end of the seventh switching tube is the second end of the voltage conversion circuit.
The apparatus of claim 4, wherein the second dotted terminal on the low voltage side of the transformer is the first terminal of the voltage conversion circuit;

or, the first voltage conversion unit further includes: a ninth switching tube; and a first end of the ninth switching tube is connected with a second dotted end on the low-voltage side of the transformer, and a second end of the ninth switching tube is a first end of the voltage conversion circuit.
The apparatus of claim 2, wherein the first voltage conversion unit comprises: a fourth bridge arm, a fifth bridge arm and a fourth capacitor;

the fourth leg includes: a seventh switching tube and an eighth switching tube; the fifth bridge arm comprises a ninth switching tube and a tenth switching tube; a first end of the seventh switching tube is connected with a first end of the eighth switching tube, and a first end of the ninth switching tube is connected with a first end of the tenth switching tube;

a second end of the seventh switching tube is connected with a first synonym end of the low-voltage side of the transformer, a second end of the eighth switching tube is connected with a second synonym end of the low-voltage side of the transformer, a second end of the ninth switching tube and a first end of the fourth capacitor are both connected with a first synonym end of the low-voltage side of the transformer, a second end of the tenth switching tube and a second end of the fourth capacitor are both connected with a second synonym end of the low-voltage side of the transformer, and a midpoint of the fourth bridge arm is connected with a midpoint of the fifth bridge arm;

The second end of the seventh switching tube is the first end of the voltage conversion circuit, and the second end of the eighth switching tube is the second end of the voltage conversion circuit.
The device of claim 2, wherein the battery pack comprises a first battery subset and a second battery subset connected in series, a negative electrode of the first battery subset being connected to a positive electrode of the second battery subset, the positive electrode of the first battery subset being a positive electrode of the battery pack, the negative electrode of the second battery subset being a negative electrode of the battery pack;

the first voltage conversion unit includes: a fourth leg comprising: a seventh switching tube and an eighth switching tube; the first end of the seventh switching tube is connected with the first end of the eighth switching tube;

the negative electrode of the first battery subgroup is connected with the synonym end of the low-voltage side of the transformer, and the midpoint of the fourth bridge arm is connected with the synonym end of the low-voltage side of the transformer;

the second end of the seventh switching tube is the first end of the voltage conversion circuit, and the second end of the eighth switching tube is the second end of the voltage conversion circuit.
The apparatus according to any one of claims 2-7, wherein the second voltage converting unit comprises: a sixth bridge arm and a seventh bridge arm;

The sixth leg includes: an eleventh switching tube and a twelfth switching tube; the seventh bridge arm comprises a thirteenth switching tube and a fourteenth switching tube;

a first end of the eleventh switching tube is connected with a first end of the twelfth switching tube, a first end of the thirteenth switching tube is connected with a first end of the fourteenth switching tube, a second end of the eleventh switching tube is connected with a second end of the thirteenth switching tube, and a second end of the twelfth switching tube is connected with a second end of the fourteenth switching tube;

the second end of the thirteenth switching tube is a third end of the voltage conversion circuit, and the second end of the fourteenth switching tube is a fourth end of the voltage conversion circuit.
The apparatus of claim 8, wherein the second voltage conversion unit further comprises: and a first end of the second capacitor is connected with a second end of the thirteenth switching tube, and a second end of the second capacitor is connected with a second end of the fourteenth switching tube.
The device according to claim 8 or 9, wherein the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the fifth inductor, the second terminal of the fifth inductor is connected to the midpoint of the sixth leg, the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the third capacitor, and the second terminal of the third capacitor is connected to the midpoint of the seventh leg.
The device according to claim 8 or 9, wherein the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the third capacitor, the second terminal of the third capacitor is connected to the midpoint of the sixth leg, the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the fifth inductor, and the second terminal of the fifth inductor is connected to the midpoint of the seventh leg.
The device according to claim 8 or 9, wherein the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the third capacitor, the second terminal of the third capacitor is connected to the first terminal of the fifth inductor, the second terminal of the fifth inductor is connected to the midpoint of the sixth leg, and the dotted terminal of the high voltage side of the transformer is connected to the midpoint of the seventh leg.
The device according to claim 8 or 9, wherein the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the fifth inductor, the second terminal of the fifth inductor is connected to the first terminal of the third capacitor, the second terminal of the third capacitor is connected to the midpoint of the sixth leg, and the dotted terminal of the high voltage side of the transformer is connected to the midpoint of the seventh leg.
The device according to claim 8 or 9, wherein the dotted terminal of the high voltage side of the transformer is connected to the midpoint of the sixth leg, the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the third capacitor, the second terminal of the third capacitor is connected to the first terminal of the fifth inductor, and the second terminal of the fifth inductor is connected to the midpoint of the seventh leg.
The device according to claim 8 or 9, wherein the dotted terminal of the high voltage side of the transformer is connected to the midpoint of the sixth leg, the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the fifth inductor, the second terminal of the fifth inductor is connected to the first terminal of the third capacitor, and the second terminal of the third capacitor is connected to the midpoint of the seventh leg.
The device according to claim 8 or 9, wherein a second end of the eleventh switching tube is connected to a first different-name end of the high-voltage side of the transformer, a second end of the twelfth switching tube is connected to a second different-name end of the high-voltage side of the transformer, a second end of the thirteenth switching tube is connected to a first same-name end of the high-voltage side of the transformer, a second end of the fourteenth switching tube is connected to a second same-name end of the high-voltage side of the transformer, a middle point of the sixth bridge arm is connected to a first end of a fifth inductor, a second end of the fifth inductor is connected to a first end of the third capacitor, and a second end of the third capacitor is connected to a middle point of the seventh bridge arm.
The device according to claim 8 or 9, wherein a second end of the eleventh switching tube is connected to a first different-name end of the high-voltage side of the transformer, a second end of the twelfth switching tube is connected to a second different-name end of the high-voltage side of the transformer, a second end of the thirteenth switching tube is connected to a first same-name end of the high-voltage side of the transformer, a second end of the fourteenth switching tube is connected to a second same-name end of the high-voltage side of the transformer, a middle point of the sixth bridge arm is connected to a first end of the third capacitor, a second end of the third capacitor is connected to a first end of the fifth inductor, and a second end of the fifth inductor is connected to a middle point of the seventh bridge arm.
The apparatus according to any one of claims 2-7, wherein the second voltage converting unit comprises: a sixth bridge arm; the sixth leg includes: an eleventh switch tube and a twelfth switch tube;

a first end of the eleventh switching tube is connected with a first end of the twelfth switching tube, a second end of the eleventh switching tube is a third end of the voltage conversion circuit, and a second end of the twelfth switching tube is a fourth end of the voltage conversion circuit;

The voltage conversion circuit further comprises a fifth end, and the fifth end of the voltage conversion circuit is connected with the midpoint of the second bridge arm.
The device according to claim 18, wherein a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the fifth inductor, a second terminal of the fifth inductor is connected to the midpoint of the sixth leg, and a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the third capacitor;

the second end of the third capacitor is a fifth end of the voltage conversion circuit.
The device according to claim 18, wherein a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the third capacitor, a second terminal of the third capacitor is connected to the midpoint of the sixth leg, and a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the fifth inductor;

the second end of the fifth inductor is a fifth end of the voltage conversion circuit.
The apparatus of claim 18, wherein a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the third capacitor, a second terminal of the third capacitor is connected to a first terminal of the fifth inductor, and a second terminal of the fifth inductor is connected to the midpoint of the sixth leg;

And the synonym end of the high-voltage side of the transformer is the fifth end of the voltage conversion circuit.
The apparatus of claim 18, wherein a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the fifth inductor, a second terminal of the fifth inductor is connected to a first terminal of the third capacitor, and a second terminal of the third capacitor is connected to the midpoint of the sixth leg;

and the synonym end of the high-voltage side of the transformer is the fifth end of the voltage conversion circuit.
The apparatus of claim 18, wherein a dotted terminal of the high voltage side of the transformer is connected to the midpoint of the sixth leg, a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the third capacitor, and a second terminal of the third capacitor is connected to a first terminal of the fifth inductor;

the second end of the fifth inductor is a fifth end of the voltage conversion circuit.
The apparatus of claim 18, wherein a dotted terminal of the high voltage side of the transformer is connected to the midpoint of the sixth leg, a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the fifth inductor, and a second terminal of the fifth inductor is connected to a first terminal of the third capacitor;

The second end of the third capacitor is a fifth end of the voltage conversion circuit.
The apparatus according to any one of claims 2-7, wherein the second voltage converting unit comprises: a sixth bridge arm; the sixth leg includes: an eleventh switch tube and a twelfth switch tube;

a first end of the eleventh switching tube is connected with a first end of the twelfth switching tube, a second end of the eleventh switching tube is connected with a first synonym end of the high-voltage side of the transformer, and a second end of the twelfth switching tube is connected with a second synonym end of the high-voltage side of the transformer;

the first dotted terminal of the high-voltage side of the transformer is a third terminal of the voltage conversion circuit, and the second dotted terminal of the high-voltage side of the transformer is a fourth terminal of the voltage conversion circuit;

and the fifth end of the voltage conversion circuit is connected with the midpoint of the second bridge arm.
The apparatus of claim 25, wherein the midpoint of the sixth leg is connected to a first terminal of a fifth inductor, and a second terminal of the fifth inductor is connected to a first terminal of the third capacitor;

the second end of the third capacitor is a fifth end of the voltage conversion circuit.
The apparatus of claim 25, wherein the midpoint of the sixth leg is connected to a first terminal of the third capacitor, and a second terminal of the third capacitor is connected to a first terminal of the fifth inductor;

the second end of the fifth inductor is a fifth end of the voltage conversion circuit.
The device of any one of claims 1-7 and 9, wherein the midpoint of the second bridge leg is used as a negative voltage input terminal of the three-bridge-leg topology device;

the three-bridge-arm topology device further comprises: a switch;

the third end of the voltage conversion circuit is respectively connected with the positive output end of the bus and the positive voltage input end through the selector switch;

the change-over switch is used for controlling the voltage conversion circuit to charge the battery pack in an external power supply mode; and when in a battery power supply mode, controlling the voltage conversion circuit to discharge the battery pack.
The apparatus of claim 28, wherein the switch comprises: the circuit comprises a first switch, a second switch and a balance component;

the third end of the voltage conversion circuit is connected with the fixed end of the first switch, the first selection end of the first switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, the second selection end of the first switch is connected with the positive voltage input end, the first end of the second switch is connected with the first end of the external power supply, the second end of the second switch is connected with the positive voltage input end, and the fourth end of the voltage conversion circuit is connected with the negative output end of the bus;

And the balance component is used for balancing the voltage between the bus and the voltage conversion circuit.
The apparatus of claim 29, wherein the balancing component is a resistor, the switch further comprising: a third switch;

the third end of the voltage conversion circuit is connected with the first end of the third switch, and the second end of the third switch is connected with the positive output end of the bus; alternatively, the third switch is connected in parallel with the resistor.
The apparatus of claim 28, wherein the switch comprises: the circuit comprises a first switch, a second switch and a balance component;

the third end of the voltage conversion circuit is connected with the first end of the first switch and the first selection end of the second switch respectively, the second end of the first switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, the second selection end of the second switch is connected with the first end of the external power supply, the fixed end of the second switch is connected with the positive voltage input end, and the fourth end of the voltage conversion circuit is connected with the negative output end of the bus;

And the balance component is used for balancing the voltage between the bus and the voltage conversion circuit.
The apparatus of claim 31, wherein the balancing component is a resistor, and the switch further comprises: a third switch;

the third end of the voltage conversion circuit is connected with the first end of the third switch, and the second end of the third switch is connected with the positive output end of the bus; alternatively, the third switch is connected in parallel with the resistor.
The apparatus of claim 28, wherein the switch comprises: the first switch, the second switch, the third switch and the balance component;

the third end of the voltage conversion circuit is connected with the first end of the first switch and the first end of the third switch respectively, the second end of the first switch is connected with the positive voltage input end, the first end of the second switch is connected with the first end of the external power supply source, the second end of the second switch is connected with the positive voltage input end, the second end of the third switch is connected with the first end of the balance component, the second end of the balance component is connected with the positive output end of the bus, and the fourth end of the voltage conversion circuit is connected with the negative output end of the bus;

And the balance component is used for balancing the voltage between the bus and the voltage conversion circuit.
The apparatus of claim 33, wherein the balancing component is a resistor, the switch further comprising: a fourth switch;

the third end of the voltage conversion circuit is connected with the first end of the fourth switch, and the second end of the fourth switch is connected with the positive output end of the bus; alternatively, the fourth switch is connected in parallel with the resistor.
The device of any one of claims 29, 31, and 33, wherein the balancing component is any one of: a piezoresistor, a thermistor with negative temperature coefficient and a third inductor.
The apparatus according to any one of claims 28-35, wherein the external power supply is a mains ac power supply;

the first end of the external power supply is the live wire of the commercial power alternating current power supply, and the second end of the external power supply is the zero line of the commercial power alternating current power supply.
The device according to any one of claims 1 to 8 and 18 to 27, wherein the midpoint of the second bridge arm is used as a negative voltage input end of the three-bridge arm topology device, and the external power supply is a commercial alternating current power supply; the first end of the external power supply is a live wire of the commercial power alternating-current power supply, and the second end of the external power supply is a zero line of the commercial power alternating-current power supply;

Or the negative output end of the bus is used as the negative voltage input end of the three-bridge-arm topological device, the external power supply is a photovoltaic direct-current power supply, the first end of the external power supply is the positive electrode of the photovoltaic direct-current power supply, and the second end of the external power supply is the negative electrode of the photovoltaic direct-current power supply.
The device according to any one of claims 1 to 8 and 18 to 27, wherein a second end of the first inductor is used as a first positive voltage input end of the three-leg topology device, a midpoint of the second leg is used as a first negative voltage input end of the three-leg topology device, the external power supply is a commercial power alternating current power supply, a first end of the external power supply is a live wire of the commercial power alternating current power supply, and a second end of the external power supply is a zero wire of the commercial power alternating current power supply;

the device further comprises: an eighth bridge arm and a sixth inductor;

the eighth bridge arm comprises a seventeenth switching tube and an eighteenth switching tube, and the seventeenth switching tube and the eighteenth switching tube are connected between the positive output end and the negative output end of the bus in series;

the middle point of the eighth bridge arm is connected with the first end of the sixth inductor, the second end of the sixth inductor is used as a second positive voltage input end of the three-bridge-arm topology device, and the negative output end of the bus is used as a second negative voltage input end of the three-bridge-arm topology device; the positive electrode of the photovoltaic direct-current power supply is connected with the second positive voltage input end, and the negative electrode of the photovoltaic direct-current power supply is connected with the second negative voltage input end.
An uninterruptible power supply system, the system comprising: an external power supply, a load, and a three-bridge arm topology device of any one of claims 1 to 37;

the first end of the external power supply is connected with the positive voltage input end of the three-bridge arm topology device, the second end of the external power supply is connected with the negative voltage input end of the three-bridge arm topology device, and the first output end and the second output end of the three-bridge arm topology device are both connected with the load.
An uninterruptible power supply system, the system comprising: a first external power supply, a second external power supply, a load, and the three-bridge arm topology apparatus of claim 38;

the first end of the first external power supply is connected with the first positive voltage input end of the three-bridge arm topology device, the second end of the first external power supply is connected with the first negative voltage input end of the three-bridge arm topology device, the first end of the second external power supply is connected with the second positive voltage input end of the three-bridge arm topology device, the second end of the second external power supply is connected with the second negative voltage input end of the three-bridge arm topology device, and the first output end and the second output end of the three-bridge arm topology device are both connected with the load.
A method of controlling a three-arm topology device, the method being for controlling the three-arm topology device of claim 29, the method comprising:

when in an external power supply mode, controlling the fixed end of a first switch to be communicated with a first selection end of the first switch, and closing a second switch;

and when the battery is in a power supply mode, the fixed end of the first switch is controlled to be communicated with the second selection end of the first switch, and the second switch is switched off.
A method of controlling a three-arm topology device, the method being for controlling the three-arm topology device of claim 30, the method comprising:

in an external power supply mode, controlling a fixed end of a first switch to be communicated with a first selection end of the first switch, closing a second switch, and controlling a third switch to be closed when a voltage difference value between a bus and a voltage conversion circuit of the three-bridge-arm topological device is smaller than or equal to a preset threshold value;

and when in a battery power supply mode, the fixed end of the first switch is controlled to be communicated with the second selection end of the first switch, and the second switch and the third switch are disconnected.
A method of controlling a three-arm topology device according to claim 31, the method comprising:

When in an external power supply mode, controlling the first switch to be closed, wherein the fixed end of the second switch is communicated with the second selection end of the second switch;

and when the battery is in a power supply mode, the first switch is controlled to be switched off, and the fixed end of the second switch is communicated with the first selection end of the second switch.
A method of controlling a three-arm topology device, the method being for controlling the three-arm topology device of claim 32, the method comprising:

when the power supply device is in an external power supply mode, controlling a first switch to be closed, communicating a fixed end of a second switch with a second selection end of the second switch, and controlling a third switch to be closed when a voltage difference value between a bus and a voltage conversion circuit of the three-bridge-arm topological device is smaller than or equal to a preset threshold value;

and when in a battery power supply mode, the third switch and the first switch are controlled to be disconnected, and the fixed end of the second switch is communicated with the first selection end of the second switch.
A method of controlling a three-arm topology device, the method being for controlling the three-arm topology device of claim 33, the method comprising:

in the external power supply mode, the first switch is controlled to be switched off, and the second switch and the third switch are controlled to be switched on;

And in the battery power supply mode, the first switch is controlled to be closed, and the second switch and the third switch are controlled to be opened.
A method of controlling a three-arm topology device according to claim 34, the method comprising:

in the external power supply mode, the first switch is controlled to be switched off, the second switch and the third switch are controlled to be switched on, and when the voltage difference value between the bus and the voltage conversion circuit of the three-bridge-arm topological device is smaller than or equal to a preset threshold value, the fourth switch is controlled to be switched on and off;

and in a battery power supply mode, the first switch is controlled to be closed, and the second switch, the third switch and the fourth switch are controlled to be opened.
A method of controlling a three-arm topology arrangement, the method being for controlling a three-arm topology arrangement according to any of claims 18-27, the method comprising:

in the first stage of the external power supply mode, the second switching tube, the fourth switching tube, the fifth switching tube and the eleventh switching tube are controlled to be conducted;

in a second stage of the external power supply mode, the second switch tube, the fourth switch tube, the fifth switch tube and the twelfth switch tube are controlled to be conducted;

In a third stage of the external power supply mode, controlling the fourth switching tube, the fifth switching tube and the eleventh switching tube to be conducted;

in a fourth stage of the external power supply mode, controlling the fourth switching tube, the fifth switching tube and the twelfth switching tube to be conducted;

in a fifth stage of the external power supply mode, the second switching tube, the fourth switching tube, the sixth switching tube and the eleventh switching tube are controlled to be conducted;

in a sixth stage of the external power supply mode, the second switching tube, the fourth switching tube, the sixth switching tube and the twelfth switching tube are controlled to be conducted;

in a seventh stage of the external power supply mode, controlling the fourth switching tube, the sixth switching tube and the eleventh switching tube to be conducted;

in an eighth stage of the external power supply mode, controlling the fourth switching tube, the sixth switching tube and the twelfth switching tube to be conducted;

in a ninth stage of the external power supply mode, controlling the conduction of a first switch tube, a third switch tube, the sixth switch tube and the twelfth switch tube;

in a tenth stage of the external power supply mode, controlling the first switch tube, the third switch tube, the sixth switch tube and the eleventh switch to be conducted;

In an eleventh stage of the external power supply mode, the third switching tube, the sixth switching tube and the twelfth switching tube are controlled to be conducted;

in a twelfth stage of the external power supply mode, the third switching tube, the sixth switching tube and the eleventh switching tube are controlled to be conducted;

in a thirteenth stage of the external power supply mode, the first switching tube, the third switching tube, the fifth switching tube and the twelfth switching tube are controlled to be conducted;

in a fourteenth stage of the external power supply mode, the first switching tube, the third switching tube, the fifth switching tube and the eleventh switching tube are controlled to be conducted;

in a fifteenth stage of the external power supply mode, the third switching tube, the fifth switching tube and the twelfth switching tube are controlled to be conducted;

in a sixteenth stage of the external power supply mode, the third switching tube, the fifth switching tube and the eleventh switching tube are controlled to be conducted;

in the first stage of the battery power supply mode, controlling the fourth switching tube, the fifth switching tube, the seventh switching tube, the tenth switching tube and the twelfth switching tube to be conducted;

In a second stage of the battery power supply mode, the fourth switching tube, the fifth switching tube, the eighth switching tube, the ninth switching tube and the eleventh switching tube are controlled to be conducted;

in a third stage of the battery power supply mode, controlling the fourth switching tube, the sixth switching tube, the seventh switching tube, the tenth switching tube and the twelfth switching tube to be conducted;

in a fourth stage of the battery power supply mode, controlling the fourth switching tube, the sixth switching tube, the eighth switching tube, the ninth switching tube and the eleventh switching tube to be conducted;

in a fifth stage of the battery power supply mode, controlling a third switching tube, the sixth switching tube, the seventh switching tube, the tenth switching tube and the twelfth switching tube to be conducted;

in a sixth stage of the battery power supply mode, the third switching tube, the sixth switching tube, the eighth switching tube, the ninth switching tube and the eleventh switching tube are controlled to be conducted;

in a seventh stage of the battery power supply mode, the third switching tube, the fifth switching tube, the seventh switching tube, the tenth switching tube and the twelfth switching tube are controlled to be conducted;

And in an eighth stage of the battery power supply mode, the third switching tube, the fifth switching tube, the eighth switching tube, the ninth switching tube and the eleventh switching tube are controlled to be conducted.
A three-leg topology device, comprising: the device comprises a battery pack, a voltage conversion circuit and a three-bridge arm circuit;

the three-bridge arm circuit includes: the bridge comprises a first bridge arm, a second bridge arm, a third bridge arm, a direct current bus capacitor and a filter;

the first bridge arm comprises a first switching tube and a second switching tube which are connected in series;

the second bridge arm comprises a third switching tube and a fourth switching tube which are connected in series;

the third bridge arm comprises a fifth switching tube and a sixth switching tube which are connected in series;

the first bridge arm, the second bridge arm, the third bridge arm and the direct current bus capacitor are connected in parallel between a positive output end and a negative output end of a bus; the middle point of the second bridge arm and the middle point of the third bridge arm are both connected with the filter;

the positive electrode of the battery pack is connected with the first end of the voltage conversion circuit, the negative electrode of the battery pack is connected with the second end of the voltage conversion circuit, the third end and the fourth end of the voltage conversion circuit are both connected with the three-bridge-arm circuit, the filter is provided with a first external connecting end of the three-bridge-arm topological device and a second external connecting end of the three-bridge-arm topological device, and the filter is connected with a load in a battery power supply mode;

The voltage conversion circuit discharges the battery pack in the battery power mode.
The apparatus of claim 48, wherein the voltage conversion circuit comprises: the first voltage conversion unit, the transformer and the LC resonant cavity; the LC resonant cavity comprises: a fifth inductor and a third capacitor;

the first voltage conversion unit is connected with the low-voltage side of the transformer, and the high-voltage side of the transformer is connected with the resonant cavity.
The apparatus of claim 49, wherein the first voltage conversion unit comprises: a fourth bridge arm and a fifth bridge arm; the fourth leg includes: a seventh switching tube and an eighth switching tube; the fifth bridge arm comprises a ninth switching tube and a tenth switching tube;

a first end of the seventh switching tube is connected with a first end of the eighth switching tube, a first end of the ninth switching tube is connected with a first end of the tenth switching tube, a second end of the seventh switching tube is connected with a second end of the ninth switching tube, and a second end of the eighth switching tube is connected with a second end of the tenth switching tube;

the midpoint of the fourth bridge arm is connected with the synonym end of the low-voltage side of the transformer, and the midpoint of the fifth bridge arm is connected with the synonym end of the low-voltage side of the transformer;

The second end of the seventh switching tube is the first end of the voltage conversion circuit, and the second end of the eighth switching tube is the second end of the voltage conversion circuit.
The apparatus of claim 49, wherein the first voltage conversion unit comprises: a seventh switching tube and an eighth switching tube;

a first end of the seventh switching tube is connected with a first homonymous end on the low-voltage side of the transformer, a first end of the eighth switching tube is connected with a heteronymous end on the low-voltage side of the transformer, and a second end of the seventh switching tube is connected with a second end of the eighth switching tube;

and the second end of the seventh switching tube is the second end of the voltage conversion circuit.
The apparatus of claim 51, wherein the second dotted terminal of the low voltage side of the transformer is the first terminal of the voltage conversion circuit;

or, the first voltage conversion unit further includes: a ninth switching tube; and a first end of the ninth switching tube is connected with a second dotted end on the low-voltage side of the transformer, and a second end of the ninth switching tube is a first end of the voltage conversion circuit.
The apparatus of claim 49, wherein the first voltage conversion unit comprises: a fourth bridge arm, a fifth bridge arm and a fourth capacitor;

The fourth leg includes: a seventh switching tube and an eighth switching tube; the fifth bridge arm comprises a ninth switching tube and a tenth switching tube; a first end of the seventh switching tube is connected with a first end of the eighth switching tube, and a first end of the ninth switching tube is connected with a first end of the tenth switching tube;

a second end of the seventh switching tube is connected with a first synonym end of the low-voltage side of the transformer, a second end of the eighth switching tube is connected with a second synonym end of the low-voltage side of the transformer, a second end of the ninth switching tube and a first end of the fourth capacitor are both connected with a first synonym end of the low-voltage side of the transformer, a second end of the tenth switching tube and a second end of the fourth capacitor are both connected with a second synonym end of the low-voltage side of the transformer, and a midpoint of the fourth bridge arm is connected with a midpoint of the fifth bridge arm;

the second end of the seventh switching tube is the first end of the voltage conversion circuit, and the second end of the eighth switching tube is the second end of the voltage conversion circuit.
The device of claim 49, wherein the battery pack comprises a first sub-battery and a second sub-battery connected in series, a negative electrode of the first sub-battery being connected to a positive electrode of the second sub-battery, the positive electrode of the first sub-battery being the positive electrode of the battery pack, and the negative electrode of the second sub-battery being the negative electrode of the battery pack;

The first voltage conversion unit includes: a fourth leg comprising: a seventh switching tube and an eighth switching tube; the first end of the seventh switching tube is connected with the first end of the eighth switching tube;

the negative electrode of the first battery subgroup is connected with the synonym end of the low-voltage side of the transformer, and the midpoint of the fourth bridge arm is connected with the synonym end of the low-voltage side of the transformer;

the second end of the seventh switching tube is the first end of the voltage conversion circuit, and the second end of the eighth switching tube is the second end of the voltage conversion circuit.
The apparatus of any one of claims 49-54, wherein the voltage conversion circuit comprises: a second voltage conversion unit including: a sixth bridge arm; the sixth leg includes: an eleventh switch tube and a twelfth switch tube;

a first end of the eleventh switching tube is connected with a first end of the twelfth switching tube, a second end of the eleventh switching tube is a third end of the voltage conversion circuit, and a second end of the twelfth switching tube is a fourth end of the voltage conversion circuit; the third end of the voltage conversion circuit is connected with the positive output end of the bus, and the fourth end of the voltage conversion circuit is connected with the negative output end of the bus;

The voltage conversion circuit further comprises a fifth end, and the fifth end of the voltage conversion circuit is connected with the midpoint of the first bridge arm.
The device according to claim 55, wherein a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the fifth inductor, a second terminal of the fifth inductor is connected to the midpoint of the sixth leg, and a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the third capacitor;

the second end of the third capacitor is a fifth end of the voltage conversion circuit.
The device according to claim 55, wherein a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the third capacitor, a second terminal of the third capacitor is connected to the midpoint of the sixth leg, and a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the fifth inductor;

the second end of the fifth inductor is a fifth end of the voltage conversion circuit.
The device of claim 55, wherein a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the third capacitor, a second terminal of the third capacitor is connected to a first terminal of the fifth inductor, and a second terminal of the fifth inductor is connected to the midpoint of the sixth leg;

And the synonym end of the high-voltage side of the transformer is the fifth end of the voltage conversion circuit.
The device according to claim 55, wherein the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the fifth inductor, the second terminal of the fifth inductor is connected to the first terminal of the third capacitor, and the second terminal of the third capacitor is connected to the midpoint of the sixth leg;

and the synonym end of the high-voltage side of the transformer is the fifth end of the voltage conversion circuit.
The device according to claim 55, wherein a dotted terminal of the high voltage side of the transformer is connected to the midpoint of the sixth leg, a dotted terminal of the high voltage side of the transformer is connected to the first terminal of the third capacitor, and the second terminal of the third capacitor is connected to the first terminal of the fifth inductor;

the second end of the fifth inductor is a fifth end of the voltage conversion circuit.
The device according to claim 55, wherein the dotted terminal of the high voltage side of the transformer is connected to the midpoint of the sixth leg, the synonym terminal of the high voltage side of the transformer is connected to the first terminal of the fifth inductor, and the second terminal of the fifth inductor is connected to the first terminal of the third capacitor;

The second end of the third capacitor is a fifth end of the voltage conversion circuit.
The apparatus of any one of claims 49-54, wherein the second voltage conversion unit comprises: a sixth bridge arm; the sixth leg includes: an eleventh switch tube and a twelfth switch tube;

a first end of the eleventh switch tube is connected with a first end of the twelfth switch tube, a second end of the eleventh switch tube is connected with a first synonym end of the high-voltage side of the transformer, and a second end of the twelfth switch tube is connected with a second synonym end of the high-voltage side of the transformer;

the first dotted terminal of the high-voltage side of the transformer is a third terminal of the voltage conversion circuit, and the second dotted terminal of the high-voltage side of the transformer is a fourth terminal of the voltage conversion circuit; the third end of the voltage conversion circuit is connected with the positive output end of the bus, and the fourth end of the voltage conversion circuit is connected with the negative output end of the bus;

the voltage conversion circuit further comprises a fifth end, and the fifth end of the voltage conversion circuit is connected with the midpoint of the first bridge arm.
The device of claim 62, wherein the midpoint of the sixth leg is connected to a first terminal of a fifth inductor, and a second terminal of the fifth inductor is connected to a first terminal of the third capacitor;

The second end of the third capacitor is a fifth end of the voltage conversion circuit.
The device of claim 62, wherein the midpoint of the sixth leg is connected to a first terminal of the third capacitor, and a second terminal of the third capacitor is connected to a first terminal of the fifth inductor;

the second end of the fifth inductor is a fifth end of the voltage conversion circuit.
The device of any one of claims 49-54, wherein a third terminal of the voltage conversion circuit is connected to the midpoint of the first leg and a fourth terminal of the voltage conversion circuit is connected to the midpoint of the second leg.
The apparatus as claimed in claim 65, wherein the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the fifth inductor, and the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the third capacitor;

the second end of the fifth inductor is the third end of the voltage conversion circuit, and the second end of the third capacitor is the fourth end of the voltage conversion circuit.
The apparatus as claimed in claim 65, wherein the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the third capacitor, and the dotted terminal of the high voltage side of the transformer is connected to the first terminal of the fifth inductor;

The second end of the third capacitor is the third end of the voltage conversion circuit, and the second end of the fifth inductor is the fourth end of the voltage conversion circuit.
The apparatus of claim 65, wherein a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the third capacitor, and a second terminal of the third capacitor is connected to a first terminal of the fifth inductor;

the second end of the fifth inductor is a third end of the voltage conversion circuit, and the synonym end of the high-voltage side of the transformer is a fourth end of the voltage conversion circuit.
The apparatus of claim 65, wherein a dotted terminal of the high voltage side of the transformer is connected to a first terminal of the fifth inductor, and a second terminal of the fifth inductor is connected to a first terminal of the third capacitor;

the second end of the third capacitor is the third end of the voltage conversion circuit, and the synonym end of the high-voltage side of the transformer is the fourth end of the voltage conversion circuit.
The apparatus of claim 65, wherein the synonym terminal of the high-voltage side of the transformer is connected to the first terminal of the third capacitor, and the second terminal of the third capacitor is connected to the first terminal of the fifth inductor;

The dotted terminal of the high-voltage side of the transformer is the third terminal of the voltage conversion circuit, and the second terminal of the fifth inductor is the fourth terminal of the voltage conversion circuit.
The device according to claim 65, wherein the synonym terminal of the high-voltage side of the transformer is connected with the first terminal of the fifth inductor, and the second terminal of the fifth inductor is connected with the first terminal of the third capacitor;

the dotted terminal of the high-voltage side of the transformer is a third terminal of the voltage conversion circuit, and the second terminal of the third capacitor is a fourth terminal of the voltage conversion circuit.
The apparatus as claimed in claim 65, wherein the second terminal of the first switching tube is connected to the first synonym terminal of the high-voltage side of the transformer, and the second terminal of the second switching tube is connected to the second synonym terminal of the high-voltage side of the transformer;

the first dotted end of the high-voltage side of the transformer is connected with the positive output end of the bus, and the second dotted end of the high-voltage side of the transformer is connected with the negative output end of the bus;

the first end of the fifth inductor is a third end of the voltage conversion circuit, the second end of the fifth inductor is connected with the first end of the third capacitor, and the second end of the third capacitor is a fourth end of the voltage conversion circuit; or the first end of the third capacitor is the third end of the voltage conversion circuit, the second end of the third capacitor is connected with the first end of the fifth inductor, and the second end of the fifth inductor is the fourth end of the voltage conversion circuit.
The device as claimed in any one of claims 65 to 72, wherein the first switching tube and the second switching tube are both diodes.
The device according to any one of claims 48-72, wherein the first external connection terminal and the second external connection terminal are connected to an external power supply source in a battery charging mode;

the voltage conversion circuit is further used for charging the battery pack in the battery charging mode.
The apparatus of any one of claims 48-74, wherein the filter comprises: a second inductor and a first capacitor; a first end of the first capacitor is a first external connection end of the three-bridge-arm topology device, and a second end of the first capacitor is a second external connection end of the three-bridge-arm topology device;

the midpoint of the third bridge arm is connected with the first end of the second inductor, the second end of the second inductor is connected with the first end of the first capacitor, and the second end of the first capacitor is connected with the midpoint of the second bridge arm;

or the midpoint of the second bridge arm is connected with the first end of the second inductor, the second end of the second inductor is connected with the second end of the first capacitor, and the first end of the first capacitor is connected with the midpoint of the third bridge arm.
The apparatus of any one of claims 48-74, wherein the filter comprises: the second inductor, the first capacitor and the fourth inductor;

the midpoint of the third bridge arm is connected with the first end of the second inductor, the second end of the second inductor is connected with the first end of the first capacitor, the second end of the first capacitor is connected with the first end of the fourth inductor, and the second end of the fourth inductor is connected with the midpoint of the second bridge arm;

the first end of the first capacitor is a first external connecting end of the three-bridge-arm topological device, and the second end of the first capacitor is a second external connecting end of the three-bridge-arm topological device.
An inversion system, the system comprising: a load, and a three-bridge arm topology device of any one of claims 48 to 76;

in a battery powered mode, the first external connection end and the second external connection end of the three-arm topology device are both connected to the load.
The system of claim 77, further comprising: an external power supply; and when the battery is in a charging mode, the first external connecting end and the second external connecting end of the three-bridge-arm topological device are both connected with the external power supply.
A method of controlling a three-arm topology arrangement, the method being for controlling a three-arm topology arrangement according to any of claims 55-64, the method comprising:

in the first stage of the battery power supply mode, the second switch tube, the eighth switch tube, the ninth switch tube and the eleventh switch tube are controlled to be conducted;

in the second stage of the battery power supply mode, the first switch tube, the seventh switch tube, the tenth switch tube and the twelfth switch tube are controlled to be conducted;

in the first stage of the battery charging mode, the second switch tube and the eleventh switch tube are controlled to be conducted;

and in the second stage of the battery charging mode, the first switching tube and the twelfth switching tube are controlled to be conducted.
A method of controlling a three-arm topology arrangement, the method being for controlling a three-arm topology arrangement according to any of claims 65-72, the method comprising:

in the first stage of the battery power supply mode, the second switching tube, the fourth switching tube, the fifth switching tube, the seventh switching tube and the tenth switching tube are controlled to be conducted;

in the second stage of the battery power supply mode, controlling the conduction of a first switch tube, the fourth switch tube, the fifth switch tube, an eighth switch tube and a ninth switch tube;

In a third stage of the battery power supply mode, controlling the second switch tube, the fourth switch tube, the sixth switch tube, the seventh switch tube and the tenth switch tube to be conducted;

in a fourth stage of the battery power supply mode, controlling the first switch tube, the fourth switch tube, the sixth switch tube, the eighth switch tube and the ninth switch tube to be conducted;

in a fifth stage of the battery power supply mode, the first switching tube, the third switching tube, the sixth switching tube, the eighth switching tube and the ninth switching tube are controlled to be conducted;

in a sixth stage of the battery power supply mode, the first switching tube, the second switching tube, the third switching tube, the sixth switching tube, the seventh switching tube and the tenth switching tube are controlled to be conducted;

in a seventh stage of the battery power supply mode, controlling the first switching tube, the third switching tube, the fifth switching tube, the eighth switching tube and the ninth switching tube to be conducted;

in an eighth stage of the battery power supply mode, controlling the first switching tube, the second switching tube, the third switching tube, the fifth switching tube, the seventh switching tube and the tenth switching tube to be conducted;

In the first stage of the battery charging mode, controlling the first switch tube, the fourth switch tube and the sixth switch tube to be conducted;

in a second stage of the battery charging mode, the second switch tube, the fourth switch tube and the sixth switch tube are controlled to be conducted;

in a third stage of the battery charging mode, controlling the first switch tube, the fourth switch tube and the fifth switch tube to be conducted;

in a fourth stage of the battery charging mode, controlling the second switch tube, the fourth switch tube and the fifth switch tube to be conducted;

in a fifth stage of the battery charging mode, controlling the second switching tube, the third switching tube and the fifth switching tube to be conducted;

in a sixth stage of the battery charging mode, the first switching tube, the third switching tube and the fifth switching tube are controlled to be conducted;

in a seventh stage of the battery charging mode, the second switching tube, the third switching tube and the sixth switching tube are controlled to be conducted;

and in an eighth stage of the battery charging mode, the first switching tube, the third switching tube and the sixth switching tube are controlled to be conducted.