CN116545287A - Soft start circuit of energy storage inverter - Google Patents
Soft start circuit of energy storage inverter Download PDFInfo
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- CN116545287A CN116545287A CN202310528663.XA CN202310528663A CN116545287A CN 116545287 A CN116545287 A CN 116545287A CN 202310528663 A CN202310528663 A CN 202310528663A CN 116545287 A CN116545287 A CN 116545287A
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- 238000004146 energy storage Methods 0.000 title claims abstract description 34
- 239000003990 capacitor Substances 0.000 claims abstract description 65
- 238000010521 absorption reaction Methods 0.000 claims description 21
- 238000007599 discharging Methods 0.000 claims description 16
- 238000010586 diagram Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 8
- 239000012943 hotmelt Substances 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5375—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with special starting equipment
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- Inverter Devices (AREA)
Abstract
A soft start circuit of an energy storage inverter, comprising: the direct-current bus capacitor, the inverter circuit and the alternating-current soft start circuit comprise a first resistor, a second resistor, a third resistor, a first relay, a second relay and a third relay. The inverter circuit is connected with the power grid according to the second port of the alternating current soft start circuit, and the alternating current soft start circuit is controlled to be closed so as to charge the direct current bus capacitor by the power grid, and finally the inverter circuit is soft started through the direct current bus capacitor. The problem that the inverter circuit is damaged due to the fact that the inverter circuit cannot be started normally and the inverter circuit is started directly under the condition that the initial value of the direct current bus capacitor voltage is zero is solved.
Description
Technical Field
The invention relates to the field of electronic circuits, in particular to a soft start circuit of an energy storage inverter.
Background
In the existing energy storage inverter circuit, a battery at a direct current side charges a direct current bus capacitor through a direct current soft starting circuit, the inverter circuit is started in a soft mode, then a grid-connected relay at an alternating current side is closed, so that the inverter circuit works in a rectifying state or an inversion state, and meanwhile safety is guaranteed through a fuse protection circuit. In the existing circuit, if the voltage of the direct current bus capacitor is zero, the inverter circuit needs to be started through the alternating current side, if the grid-connected relay is directly closed, the power grid is rectified to the bus capacitor through the IGBT body diode of the inverter circuit in an uncontrolled manner, but because the impedance of a circuit loop is very low, a large impact current is generated, and the IGBT body diode is damaged before the fuse is fused.
Disclosure of Invention
The embodiment of the invention provides a soft start circuit of an energy storage inverter, which solves the problem that the inverter cannot be started normally and is damaged by directly starting the inverter under the condition that the initial value of the voltage of a direct current bus capacitor is zero by measuring the soft start inverter of the soft start circuit through alternating current.
In a first aspect, an embodiment of the present invention provides a soft start circuit of an energy storage inverter, including a dc bus capacitor, an inverter circuit, and an ac soft start circuit, where the ac soft start circuit includes a first resistor, a second resistor, a third resistor, a first relay, a second relay, and a third relay;
the direct current bus capacitor is connected with the inverter circuit in parallel; the second port of the inverter circuit is connected with the first port of the first relay, the third port of the inverter circuit is connected with the first port of the second relay, and the fourth port of the inverter circuit is connected with the first port of the third relay; the second port of the first relay is connected with the first resistor; the second port of the second relay is connected with a second resistor; the second port of the third relay is connected with a third resistor;
the inverter circuit is used for controlling the alternating current soft start circuit to be closed if the first port of the inverter circuit and the first port of the direct current bus capacitor are connected with the direct current load so as to realize that the power grid charges the direct current bus capacitor, wherein the second port of the alternating current soft start circuit comprises a first resistor, a second resistor and a second port of a third resistor;
the direct current bus capacitor is used for soft starting the inverter circuit.
With reference to the first aspect, in one possible embodiment, a first port of the inverter circuit and a first port of the dc bus capacitor are connected to a first port of the dc load, and a fifth port of the inverter circuit and a second port of the dc bus capacitor are connected to a second port of the dc load; the soft start circuit of the energy storage inverter further comprises a first grid-connected relay, a second grid-connected relay and a third grid-connected relay; the first port of the first grid-connected relay is connected with the second port of the inverter circuit, and the second port of the first grid-connected relay is connected with a power grid; the first port of the second grid-connected relay is connected with the third port of the inverter circuit, and the second port of the second grid-connected relay is connected with a power grid; the first port of the third grid-connected relay is connected with the fourth port of the inverter circuit, and the second port of the first grid-connected relay is connected with a power grid;
the inverter circuit is further used for controlling the first relay, the second relay and the third relay to be closed and opened and controlling the first grid-connected relay, the second grid-connected relay and the third grid-connected relay to be closed if the voltage of the direct current bus is larger than the second preset voltage within the first preset time period after the first relay, the second relay and the third relay are closed; the direct current bus voltage is the voltage between the first port of the direct current load and the first port of the direct current bus capacitor.
With reference to the first aspect, in one possible embodiment, the soft start circuit of the energy storage inverter further includes: a rapid discharge circuit; the first port of the rapid discharging circuit is connected with the first port of the direct current load; the second port of the rapid discharging circuit is connected with the second port of the direct current load; before the first relay, the second relay and the third relay in the alternating current soft start circuit are controlled to be closed, the inverter circuit is further specifically used for: when the voltage of the direct current bus is larger than a first preset voltage, the rapid discharging circuit is controlled to be closed, so that the voltage of the direct current bus is released to the rapid discharging circuit; and when the voltage of the direct current bus is smaller than the first preset voltage, the quick discharging circuit is controlled to be disconnected.
In the embodiment of the application, before the alternating-current soft start circuit is controlled to be closed, if the voltage of the direct-current bus is larger than the first preset voltage, the inverter circuit controls the quick discharge circuit to be closed; until the dc bus voltage is less than the first preset voltage. The direct-current bus voltage is discharged to a safe voltage range, so that the damage risk of the electronic element in the circuit bearing larger impact current during starting is reduced.
With reference to the first aspect, in one possible embodiment, if the first port of the inverter circuit and the first port of the dc bus capacitor are connected to a battery, the soft start circuit of the energy storage inverter further includes: the direct-current soft start relay, the direct-current soft start resistor, the direct-current contactor, the absorption circuit and the quick turn-off circuit;
the first port of the inverter circuit and the first port of the direct current bus capacitor are connected with the first port of the battery, and the fifth port of the inverter circuit and the second port of the direct current bus capacitor are connected with the second port of the battery; the direct-current contactor is connected with the direct-current soft start relay in parallel, and a first port of the direct-current contactor and a first port of the direct-current soft start relay are connected with a first port of the direct-current load; the direct-current soft start relay is connected with the direct-current soft start resistor in series, and a second port of the direct-current soft start relay is connected with a first port of the direct-current soft start resistor; the second port of the direct current contactor and the second port of the direct current soft start resistor are connected with the first port of the direct current bus capacitor; the first port of the quick turn-off circuit is connected with the second port of the direct current contactor, and the second port of the quick turn-off circuit is connected with the first port of the direct current bus capacitor and the first port of the inverter circuit; the first port of the absorption circuit is connected with the second port of the direct current contactor, and the second port of the absorption circuit is connected with the second port of the direct current load;
the inverter circuit is also specifically used for controlling the direct-current soft start relay to be closed; after the direct-current soft start relay is closed, if the direct-current bus voltage is larger than the second preset voltage within the first preset time period, the quick turn-off circuit is controlled to be closed, and then the direct-current contactor is controlled to be closed; after the direct-current contactor is closed, the direct-current soft start relay is controlled to be opened, and the first grid-connected relay, the second grid-connected relay and the third grid-connected relay are controlled to be closed;
wherein the dc bus voltage is a voltage between the first port of the battery and the first port of the dc bus capacitor; the absorption circuit is used for reducing the voltage stress of the turn-off circuit.
In the embodiment of the application, it can be seen that when the second port of the ac soft start circuit is connected to an ac load, the inverter circuit can also close the soft start inverter circuit by controlling the dc soft start relay. The risk of damaging electronic elements in the circuit when the impact current is large in the soft start process of the circuit is reduced by controlling the quick turn-off circuit and the absorption circuit.
With reference to the first aspect, in one possible embodiment, if a soft start circuit of the energy storage inverter is shorted, the inverter circuit is further configured to control the quick turn-off circuit to be closed.
In the embodiment of the application, it can be seen that when the circuit is short-circuited, the inverter circuit controls the quick turn-off circuit to be closed, so that the problem that the inverter circuit cannot be timely disconnected to protect electronic elements in the inverter circuit when the circuit is short-circuited is solved.
With reference to the first aspect, in one possible embodiment, if the second port of the ac soft start circuit is connected to the power grid, the inverter circuit is further configured to control the quick shutdown circuit to be closed before controlling the ac soft start circuit to be closed; and then controlling the direct current contactor to be closed.
With reference to the first aspect, in one possible embodiment, the soft start circuit of the energy storage inverter further includes: a fuse; the first port of the fuse is connected with the first port of the direct current load or the battery, and the second port of the fuse is connected with the first port of the direct current soft start relay and the first port of the direct current contactor.
With reference to the first aspect, in one possible embodiment, the first passive filter, the second passive filter, and the third passive filter;
the first port of the first passive filter is connected with the second port of the inverter circuit, and the second port of the first passive filter is connected with the first port of the first relay and the first port of the first grid-connected relay; the first port of the second passive filter is connected with the third port of the inverter circuit, and the second port of the second passive filter is connected with the first port of the second relay and the first port of the second grid-connected relay; the first port of the third passive filter is connected with the fourth port of the inverter circuit, and the second port of the third passive filter is connected with the first port of the third relay and the first port of the third grid-connected relay;
the first passive filter, the second passive filter and the third passive filter respectively filter out harmonic waves passing through the first passive filter, the second passive filter and the third passive filter.
Through implementing the circuit in this application embodiment, through soft start inverter circuit of soft start circuit, solved under the condition that direct current bus capacitance voltage initial value is zero, inverter circuit can't normally start, direct start inverter circuit leads to inverter circuit's problem damaged. Through the absorption circuit, when the voltage of the direct current bus is larger, the voltage of the direct current bus is discharged to a safe voltage range, and the damage risk that electronic elements in the circuit bear larger impact current during starting is reduced. The circuit is short-circuited, and the quick turn-off circuit is controlled to be closed through the inverter circuit, so that the problem that the inverter circuit cannot timely protect elements in the inverter circuit by controlling to turn off the direct current contactor and the grid-connected relay is solved.
These and other aspects of the invention will be more readily apparent from the following description of the embodiments.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a soft start circuit connection of an energy storage inverter according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a soft start circuit connection of another energy storage inverter according to an embodiment of the present disclosure;
fig. 3 is a schematic connection diagram of a fast discharging circuit according to an embodiment of the present disclosure;
fig. 4 is a schematic diagram of a soft start circuit connection of a third energy storage inverter according to an embodiment of the present disclosure;
fig. 5 is a schematic connection diagram of a fuse according to an embodiment of the present application;
fig. 6 is a schematic connection diagram of a passive filter according to an embodiment of the present application;
fig. 7 is a schematic diagram of a soft start circuit connection of a three-level inverter according to an embodiment of the present disclosure;
fig. 8 is a flowchart of a method for soft-starting an inverter circuit of a dc soft-start circuit according to an embodiment of the present application;
fig. 9 is a flowchart of a method for soft-starting an inverter circuit of an ac soft-start circuit according to an embodiment of the present application.
Detailed Description
Embodiments of the present application are described below with reference to the accompanying drawings.
Referring to fig. 1, fig. 1 is a schematic diagram of a soft start circuit connection of an energy storage inverter according to an embodiment of the present invention. As shown in fig. 1, the soft start circuit of the energy storage inverter includes: the direct current bus capacitor 101, the inverter circuit 102 and the alternating current soft start circuit 103, wherein the alternating current soft start circuit 103 comprises a first relay 1031, a second relay 1032, a third relay 1033, a first resistor 1034, a second resistor 1035 and a third resistor 1036.
The direct current bus capacitor 101 is connected with the inverter circuit 102 in parallel; a second port of the inverter circuit 102 is connected to the first port of the first relay 1031, a third port of the inverter circuit 102 is connected to the first port of the second relay 1032, and a fourth port of the inverter circuit 102 is connected to the first port of the third relay 1033; the second port of the first relay 1031 is connected to the first resistor 1034; a second port of the second relay 1032 is connected to a second resistor 1035; the second port of the third relay 1033 is connected to a third resistor 1036.
The working principle of the soft start circuit of the energy storage inverter is described below.
The first port of the dc bus capacitor and the first port of the inverter circuit may be connected to a dc power supply for supplying power, where the dc power supply is used for starting the inverter circuit, but when the dc power supply capacity is zero or the first port of the dc bus capacitor and the first port of the inverter circuit are connected to a dc load, the inverter circuit needs to be started by connecting the second port of the ac soft start circuit to an ac power supply. The inverter circuit here may be a three-phase inverter, for example. The second port of the first resistor, the second port of the second resistor and the second port of the third resistor can be respectively connected with three live wires of a three-phase alternating current power supply. In addition, the inverter circuit can also comprise a micro control unit (Microcontroller Unit; MCU), and the DC bus voltage in the embodiment of the application can be obtained through the MCU to control the on and off of the first relay, the second relay and the third relay. The first relay, the second relay and the third relay are controlled to be closed through the inverter circuit, and the direct current bus capacitor is charged, so that the inverter circuit is started in a soft mode.
In one possible embodiment, a first port of the inverter circuit and a first port of the dc bus capacitor are connected to a first port of the dc load, and a fifth port of the inverter circuit and a second port of the dc bus capacitor are connected to a second port of the dc load; the soft start circuit of the energy storage inverter further comprises a first grid-connected relay, a second grid-connected relay and a third grid-connected relay; the first port of the first grid-connected relay is connected with the second port of the inverter circuit, and the second port of the first grid-connected relay is connected with a power grid; the first port of the second grid-connected relay is connected with the third port of the inverter circuit, and the second port of the second grid-connected relay is connected with a power grid; the first port of the third grid-connected relay is connected with the fourth port of the inverter circuit, and the second port of the first grid-connected relay is connected with a power grid; the inverter circuit is further used for controlling the first relay, the second relay and the third relay to be closed and opened and controlling the first grid-connected relay, the second grid-connected relay and the third grid-connected relay to be closed if the voltage of the direct current bus is larger than the second preset voltage within the first preset time period after the first relay, the second relay and the third relay are closed; the direct current bus voltage is the voltage between the first port of the direct current load and the first port of the direct current bus capacitor.
Referring to fig. 2, fig. 2 is a schematic diagram of a soft start circuit connection of another energy storage inverter according to an embodiment of the present application, where the embodiment of the present application further includes a dc load and a first grid-connected relay, a second grid-connected relay and a third grid-connected relay based on the circuit of fig. 1. The first port of the first grid-connected relay is connected with the second port of the inverter circuit, and the second port of the first grid-connected relay is connected with a power grid; the first port of the second grid-connected relay is connected with the third port of the inverter circuit, and the second port of the second grid-connected relay is connected with a power grid; the first port of the third grid-connected relay is connected with the fourth port of the inverter circuit, and the second port of the first grid-connected relay is connected with the power grid.
The working principle of the soft start circuit of the energy storage inverter is described below.
The inverter circuit controls a first relay, a second relay and a third relay in the alternating current soft start circuit to acquire direct current bus voltage after the first relay, the second relay and the third relay are closed, wherein the voltage between a first port of a direct current bus voltage direct current load and a first port of a direct current bus capacitor is obtained. When the voltage of the direct current bus is larger than the second preset voltage within the first preset time, the completion of charging of the direct current bus capacitor can be judged, and the soft start of the inverter circuit is successful. At the moment, the first relay, the second relay and the third relay can be controlled to be opened, the first grid-connected relay is controlled to be closed, and the second grid-connected relay and the third grid-connected relay enable the inverter circuit to work in a rectifying state.
In one possible embodiment, the soft start circuit of the energy storage inverter further comprises: a rapid discharge circuit; the first port of the rapid discharging circuit is connected with the first port of the direct current load; the second port of the rapid discharging circuit is connected with the second port of the direct current load; before the first relay, the second relay and the third relay in the alternating current soft start circuit are controlled to be closed, the inverter circuit is further specifically used for: when the voltage of the direct current bus is larger than a first preset voltage, the rapid discharging circuit is controlled to be closed, so that the voltage of the direct current bus is released to the rapid discharging circuit; and when the voltage of the direct current bus is smaller than the first preset voltage, the quick discharging circuit is controlled to be disconnected.
Specifically, referring to fig. 3, fig. 3 is a schematic connection diagram of a fast discharging circuit provided in an embodiment of the present application, where the fast discharging circuit is connected in parallel with a dc bus capacitor; before the direct-current soft start circuit is controlled to be closed, the voltage on the direct-current bus voltage needs to be detected, if the direct-current bus voltage is larger than a first preset voltage, the quick discharge circuit is closed, the voltage on the direct-current bus voltage is discharged through the quick discharge circuit until the direct-current bus voltage is smaller than the first preset voltage, and the first preset voltage is smaller than a second preset voltage.
In the embodiment of the application, before the alternating-current soft start circuit is controlled to be closed, if the voltage of the direct-current bus is larger than the first preset voltage, the inverter circuit controls the quick discharge circuit to be closed; until the dc bus voltage is less than the first preset voltage. The direct-current bus voltage is discharged to a safe voltage range, so that the damage risk of the electronic element in the circuit bearing larger impact current during starting is reduced.
In one possible embodiment, if the first port of the inverter circuit and the first port of the dc bus capacitor are connected to the battery, the soft start circuit of the energy storage inverter further includes: the direct-current soft start relay, the direct-current soft start resistor, the direct-current contactor, the absorption circuit and the quick turn-off circuit; the first port of the inverter circuit and the first port of the direct current bus capacitor are connected with the first port of the battery, and the fifth port of the inverter circuit and the second port of the direct current bus capacitor are connected with the second port of the battery; the direct-current contactor is connected with the direct-current soft start relay in parallel, and a first port of the direct-current contactor and a first port of the direct-current soft start relay are connected with a first port of the direct-current load; the direct-current soft start relay is connected with the direct-current soft start resistor in series, and a second port of the direct-current soft start relay is connected with a first port of the direct-current soft start resistor; the second port of the direct current contactor and the second port of the direct current soft start resistor are connected with the first port of the direct current bus capacitor; the first port of the quick turn-off circuit is connected with the second port of the direct current contactor, and the second port of the quick turn-off circuit is connected with the first port of the direct current bus capacitor and the first port of the inverter circuit; the first port of the absorption circuit is connected with the second port of the direct current contactor, and the second port of the absorption circuit is connected with the second port of the direct current load; the inverter circuit is also specifically used for controlling the direct-current soft start relay to be closed; after the direct-current soft start relay is closed, if the direct-current bus voltage is larger than the second preset voltage within the first preset time period, the quick turn-off circuit is controlled to be closed, and then the direct-current contactor is controlled to be closed; after the direct-current contactor is closed, the direct-current soft start relay is controlled to be opened, and the first grid-connected relay, the second grid-connected relay and the third grid-connected relay are controlled to be closed; wherein the dc bus voltage is a voltage between the first port of the battery and the first port of the dc bus capacitor; the absorption circuit is used for reducing the voltage stress of the turn-off circuit.
Referring to fig. 4, fig. 4 is a schematic diagram of a soft start circuit connection of a third energy storage inverter provided in an embodiment of the present application, where based on the circuit of fig. 2, the embodiment of the present application further includes a dc soft start relay, a dc soft start resistor, a dc contactor, a fast turn-off circuit and an absorption circuit, a first port of the inverter circuit and a first port of a dc bus capacitor are connected to a first port of a battery, and a fifth port of the inverter circuit and a second port of the dc bus capacitor are connected to a second port of the battery; the direct-current contactor is connected with the direct-current soft start relay in parallel, and a first port of the direct-current contactor and a first port of the direct-current soft start relay are connected with a first port of the direct-current load; the direct-current soft start relay is connected with the direct-current soft start resistor in series, and a second port of the direct-current soft start relay is connected with a first port of the direct-current soft start resistor; the second port of the direct current contactor and the second port of the direct current soft start resistor are connected with the first port of the direct current bus capacitor; the first port of the quick turn-off circuit is connected with the second port of the direct current contactor, and the second port of the quick turn-off circuit is connected with the first port of the direct current bus capacitor and the first port of the inverter circuit; the first port of the absorption circuit is connected with the second port of the direct current contactor, and the second port of the absorption circuit is connected with the second port of the direct current load.
The working principle of the soft start circuit of the energy storage inverter is described below.
When the dc bus capacitor and the inverter circuit are connected to the battery on the dc side, the inverter circuit can be soft-started by the battery. The inverter circuit controls the direct-current soft start relay to be closed, and after the direct-current soft start relay is closed, if the direct-current bus voltage is greater than the second preset voltage within the first preset time period, the inverter circuit is successfully started in a soft mode. The dc soft start relay may be a diode, and since the on time node of the diode is not known, when the dc soft start relay is a diode, whether the inverter circuit is successfully soft started needs to be judged by acquiring whether the dc bus voltage is greater than a second preset threshold value, and when the dc bus voltage is greater than the second preset threshold value, the inverter circuit is successfully soft started. After the soft start of the inverter circuit is successful, in order to reduce the overlarge impact current borne by the absorption circuit as much as possible, the quick turn-off circuit is firstly closed, and then the direct current contactor is closed, so that the inverter circuit works in a rectifying state or an inversion state. When the direct-current soft start relay is not a diode, the direct-current soft start relay also needs to be disconnected. The fast turn-off circuit may include an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), a triode, or a MOS transistor.
In the embodiment of the application, it can be seen that when the second port of the ac soft start circuit is connected to an ac load, the inverter circuit can also close the soft start inverter circuit by controlling the dc soft start relay. The risk of damaging electronic elements in the circuit when the impact current is large in the soft start process of the circuit is reduced by controlling the quick turn-off circuit and the absorption circuit.
In one possible embodiment, the inverter circuit is further configured to control the quick turn-off circuit to close if a short circuit occurs in the soft start circuit of the energy storage inverter.
Specifically, if a short circuit occurs suddenly during the operation of the inverter circuit, since the fuse has a hot melt value I2T that is often greater than that of the IGBT body diode in the inverter circuit, the IGBT body diode of the IGBT inverter circuit is already damaged by overcurrent before the fuse plays a role in protection, and thus the inverter circuit is required to control the quick turn-off circuit to be turned on.
In the embodiment of the application, it can be seen that when the circuit is short-circuited, the inverter circuit controls the quick turn-off circuit to be closed, so that the problem that the inverter circuit cannot be timely disconnected to protect electronic elements in the inverter circuit when the circuit is short-circuited is solved.
In one possible embodiment, if the second port of the ac soft start circuit is connected to the power grid, the inverter circuit is further configured to control the quick-turn-off circuit to be turned on before the first relay, the second relay, and the third relay in the ac soft start circuit are controlled to be turned on; and then controlling the direct current contactor to be closed.
Specifically, when the inverter circuit is soft-started by the ac soft-start circuit, if the load is a larger capacitive load, after the ac soft-start, the dc bus capacitor is electrified, and then the fast turn-off circuit and the dc contactor are turned on, a large surge current is inevitably generated, and the surge current damages IGBTs in the fast turn-off circuit and the inverter circuit.
In one possible embodiment, the soft start circuit of the energy storage inverter further comprises: a fuse; the first port of the fuse is connected with the first port of the direct current load or the battery, and the second port of the fuse is connected with the first port of the direct current soft start relay and the first port of the direct current contactor.
Specifically, referring to fig. 5, fig. 5 is a schematic connection diagram of a fuse according to an embodiment of the present application. The first port of the fuse is connected with the first port of the direct current load or the battery, and the second port of the fuse is connected with the first port of the direct current soft start relay and the first port of the direct current contactor. The protection circuit is blown when the current through the fuse exceeds the I2T of the fuse.
In one possible embodiment, a first passive filter, a second passive filter, and a third passive filter; the first port of the first passive filter is connected with the second port of the inverter circuit, and the second port of the first passive filter is connected with the first port of the first relay and the first port of the first grid-connected relay; the first port of the second passive filter is connected with the third port of the inverter circuit, and the second port of the second passive filter is connected with the first port of the second relay and the first port of the second grid-connected relay; the first port of the third passive filter is connected with the fourth port of the inverter circuit, and the second port of the third passive filter is connected with the first port of the third relay and the first port of the third grid-connected relay; the first passive filter, the second passive filter and the third passive filter respectively filter out harmonic waves passing through the first passive filter, the second passive filter and the third passive filter.
Specifically, referring to fig. 6, fig. 6 is a schematic connection diagram of a passive filter provided in the embodiment of the present application, wherein a passive filter circuit is connected before a first relay, a second relay and a third relay, respectively, and includes an inductor and a capacitor, a first port of the inductor L is connected to an inverter circuit, a second port of the inductor L is connected to a first port of the capacitor C and a first port of the first relay, and a second port of the capacitor C is grounded. The harmonics passing through the passive filter can be filtered by adding the passive filter, only the connection of the passive filter before the first relay is illustrated here, the passive filters of the second relay and the third relay are connected in the same connection method.
Referring to fig. 7, fig. 7 is a schematic diagram of a soft start circuit connection of a three-level inverter according to an embodiment of the present application. The power supply circuit comprises fuses F1, direct-current soft start circuits D1 and Rs, direct-current contactors K1, a quick turn-off circuit Q1, absorption circuits R3 and Cs, quick discharge circuits K2 and R4, direct-current bus capacitors BUSN, first passive filter circuits La and Ca, second passive filter circuits Lb and Cb, third passive filter circuits Lc and Cc, first alternating-current soft start circuits Ks1 and R1, second alternating-current soft start circuits Ks2 and R2, third alternating-current soft start circuits Ks3 and R3, first grid-connected relays Ka, second grid-connected relays Kb and third grid-connected relays Kc.
The first port of F1 is connected with the battery, and the second port is connected with the first port of D1 and the first port of K1; the second port of the D1 is connected with the first port of the Rs, and the second port of the Rs is connected with the first port of the BUSN and the first port of the three-level inverter circuit; the second port of K1 is connected with the first port of Q1 and the first port of R3; the second port of the Q1 is connected with the first port of the BUSN and the first port of the three-level inverter circuit; the second port of R3 is connected with the first port of Cs, and the first port of Cs is connected with the second port of the battery; the first port of K2 is connected with the second port of Q1, the second port of K2 is connected with the first port of R4, and the second port of R4 is connected; the second port of BUSN is connected with the second port of the battery; the second port of the three-level inverter circuit is connected with the first port of La, the third port of the three-level inverter circuit is connected with the first port of Lb, and the fourth port of the three-level inverter circuit is connected with the first port of Lc; the fifth port of the three-level inverter circuit is connected with the second port of the battery; the second port of La is connected with the first port of Ca, the first port of Ks1 and the first port of Ka; the second port of Lb is connected with the first port of Cb, the first port of Ks2 and the first port of Kb; the second port of Lc is connected to the first port of Cc, the first port of Ks3 and the first port of Kc; the second port of Ks1 is connected with the first port of R1, and the second port of R1 is connected with a power grid; the second port of Ks2 is connected with the first port of R2, and the second port of R2 is connected with the power grid; the second port of Ks3 is connected with the first port of R3, and the second port of R3 is connected with the power grid; the second ports of Ka, kb and Kc are connected to the grid.
Specifically, referring to fig. 8, fig. 8 is a flowchart of a method for soft-starting an inverter circuit of a dc soft-start circuit according to an embodiment of the present application. When the battery capacity is not zero, the three-level inverter circuit charges BUSN through D1 and Rs, so that the BUSN soft start is enabled to be a diode, the starting time for starting charging the direct current bus capacitor cannot be obtained, and therefore whether the three-level inverter circuit is successfully soft started is judged through the direct current bus voltage. And when the voltage of the direct current bus is larger than a first preset threshold value, judging that the soft start of the three-level inverter circuit is successful. After the soft start of the three-level inverter circuit is successful, the Q1 and K1 inverter circuits are closed successively, and normal operation is started. Finally Ka, kb and Kc are closed so that the three-level inverter circuit works in a PWM rectification state or an inversion state.
Referring to fig. 9, fig. 9 is a flowchart of a method for soft-starting an inverter circuit of an ac soft-start circuit according to an embodiment of the present application, if the initial values of the battery capacity and the dc bus capacitor voltage are zero, or if the battery is a dc load, the voltage on the dc bus is detected first, if the dc bus voltage is not less than a first preset voltage, the K2 needs to be controlled to be closed, and the dc bus voltage is discharged to be less than the first preset voltage. If the voltage of the direct current bus is smaller than the first preset voltage, Q1 and K1 are closed successively. Then Ks1, ks2 and Ks3 are closed, and BUSN is charged through an alternating current power grid, so that BUSN is started in a soft mode. When the voltage of the direct current bus is larger than the second preset voltage within the first preset time, the soft start of the three-level inverter circuit is successful, ks1, ks2 and Ks3 are disconnected after the soft start of the three-level inverter circuit is successful, and Ka, kb and Kc are closed to enable the three-level inverter circuit to work in a rectifying state. When the three-level inverter circuit is in short circuit during operation, the Q1 is controlled to be disconnected to protect electronic elements such as IGBT body diodes and the like in the three-level inverter circuit.
Through the circuit in this application embodiment, control soft start circuit soft start inverter circuit has solved under the condition that direct current bus capacitance voltage initial value is zero, and inverter circuit can't normally start, and direct start inverter circuit leads to inverter circuit's problem of damage. Through the absorption circuit, when the voltage of the direct current bus is larger, the voltage of the direct current bus is discharged to a safe voltage range, and the damage risk that electronic elements in the circuit bear larger impact current during starting is reduced. The circuit is short-circuited, and the quick turn-off circuit is controlled to be closed through the inverter circuit, so that the problem that the inverter circuit cannot timely protect elements in the inverter circuit by controlling to turn off the direct current contactor and the grid-connected relay is solved.
The foregoing has outlined rather broadly the more detailed description of embodiments of the invention, wherein the principles and embodiments of the invention are explained in detail using specific examples, the above examples being provided solely to facilitate the understanding of the method and core concepts of the invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Claims (8)
1. The soft start circuit of the energy storage inverter is characterized by comprising a direct current bus capacitor, an inverter circuit and an alternating current soft start circuit, wherein the alternating current soft start circuit comprises a first resistor, a second resistor, a third resistor, a first relay, a second relay and a third relay;
the direct current bus capacitor is connected with the inverter circuit in parallel; the second port of the inverter circuit is connected with the first port of the first relay, the third port of the inverter circuit is connected with the first port of the second relay, and the fourth port of the inverter circuit is connected with the first port of the third relay; the second port of the first relay is connected with the first port of the first resistor phase; the second port of the second relay is connected with the first port of the second resistor; the second port of the third relay is connected with the first port of the third resistor; the second port of the first resistive phase, the second port of the second resistive phase, and the second port of the third resistive phase are connected to a power grid;
the inverter circuit is used for controlling the first relay, the second relay and the third relay in the alternating current soft start circuit to be closed if the first port of the inverter circuit and the first port of the direct current bus capacitor are connected to a direct current load so as to charge the direct current bus capacitor by a power grid, wherein the second port of the alternating current soft start circuit comprises the second ports of the first resistor, the second resistor and the third resistor;
the direct current bus capacitor is used for soft starting the inverter circuit.
2. The circuit of claim 1, wherein a first port of the inverter circuit and a first port of the dc bus capacitor are connected to a first port of a dc load, and a fifth port of the inverter circuit and a second port of the dc bus capacitor are connected to a second port of the dc load; the soft start circuit of the energy storage inverter further comprises a first grid-connected relay, a second grid-connected relay and a third grid-connected relay; the first port of the first grid-connected relay is connected with the second port of the inverter circuit, and the second port of the first grid-connected relay is connected with a power grid; the first port of the second grid-connected relay is connected with the third port of the inverter circuit, and the second port of the second grid-connected relay is connected with a power grid; the first port of the third grid-connected relay is connected with the fourth port of the inverter circuit, and the second port of the first grid-connected relay is connected with a power grid;
the inverter circuit is further used for controlling the first relay, the second relay and the third relay to be closed and opened and controlling the first grid-connected relay, the second grid-connected relay and the third grid-connected relay to be closed if the direct current bus voltage is larger than a second preset voltage within a first preset duration after the first relay, the second relay and the third relay are closed;
the direct current bus voltage is the voltage between the first port of the direct current load and the first port of the direct current bus capacitor.
3. The circuit of claim 2, wherein the soft start circuit of the energy storage inverter further comprises: a rapid discharge circuit;
the first port of the rapid discharge circuit is connected with the first port of the direct current load; the second port of the rapid discharge circuit is connected with the second port of the direct current load;
before the first relay, the second relay and the third relay in the alternating current soft start circuit are controlled to be closed, the inverter circuit is further specifically configured to:
when the voltage of the direct current bus is larger than a first preset voltage, controlling the quick discharging circuit to be closed so that the voltage of the direct current bus is released to the quick discharging circuit; and when the voltage of the direct current bus is smaller than a first preset voltage, the quick discharging circuit is controlled to be disconnected.
4. The circuit of claim 2, wherein if the first port of the inverter circuit and the first port of the dc bus capacitor are connected to a battery, the soft start circuit of the energy storage inverter further comprises: the direct-current soft start relay, the direct-current soft start resistor, the direct-current contactor, the absorption circuit and the quick turn-off circuit;
the first port of the inverter circuit and the first port of the direct current bus capacitor are connected with the first port of the battery, and the fifth port of the inverter circuit and the second port of the direct current bus capacitor are connected with the second port of the battery; the direct-current contactor is connected with the direct-current soft start relay in parallel, and a first port of the direct-current contactor and a first port of the direct-current soft start relay are connected with a first port of the direct-current load; the direct-current soft start relay is connected with the direct-current soft start resistor in series, and a second port of the direct-current soft start relay is connected with a first port of the direct-current soft start resistor; the second port of the direct current contactor and the second port of the direct current soft start resistor are connected with the first port of the direct current bus capacitor; the first port of the quick turn-off circuit is connected with the second port of the direct current contactor, and the second port of the quick turn-off circuit is connected with the first port of the direct current bus capacitor and the first port of the inverter circuit; the first port of the absorption circuit is connected with the second port of the direct current contactor, and the second port of the absorption circuit is connected with the second port of the direct current load;
the inverter circuit is also specifically used for controlling the direct-current soft start relay to be closed; after the direct-current soft start relay is closed, if the direct-current bus voltage is larger than a second preset voltage within a first preset time period, the quick turn-off circuit is controlled to be closed, and then the direct-current contactor is controlled to be closed; after the direct current contactor is closed, the direct current soft start relay is controlled to be opened, and the first grid-connected relay, the second grid-connected relay and the third grid-connected relay are controlled to be closed;
wherein the dc bus voltage is a voltage between the first port of the battery and the first port of the dc bus capacitor;
the absorption circuit is used for reducing the voltage stress of the quick turn-off circuit.
5. The circuit of any of claims 1-4, wherein the inverter circuit is further configured to control the quick-turn-off circuit to close if a soft start circuit of the energy storage inverter is shorted.
6. The circuit of any of claims 1-4, wherein if the second port of the ac soft start circuit is connected to a power grid, the inverter circuit is further configured to control the quick turn-off circuit to close and then control the dc contactor to close before controlling the first, second, and third relays in the ac soft start circuit to close.
7. The circuit of any of claims 1-4, wherein the soft start circuit of the energy storage inverter further comprises: a fuse;
the first port of the fuse is connected with the first port of the direct current load or the battery, and the second port of the fuse is connected with the first port of the direct current soft start relay and the first port of the direct current contactor.
8. The circuit of any of claims 1-4, wherein the soft start circuit of the energy storage inverter further comprises: a first passive filter, a second passive filter, and a third passive filter;
the first port of the first passive filter is connected with the second port of the inverter circuit, and the second port of the first passive filter is connected with the first port of the first relay and the first port of the first grid-connected relay; the first port of the second passive filter is connected with the third port of the inverter circuit, and the second port of the second passive filter is connected with the first port of the second relay and the first port of the second grid-connected relay; the first port of the third passive filter is connected with the fourth port of the inverter circuit, and the second port of the third passive filter is connected with the first port of the third relay and the first port of the third grid-connected relay;
the first passive filter, the second passive filter and the third passive filter respectively filter out harmonic waves passing through the first passive filter, the second passive filter and the third passive filter.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310528663.XA CN116545287A (en) | 2023-05-09 | 2023-05-09 | Soft start circuit of energy storage inverter |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310528663.XA CN116545287A (en) | 2023-05-09 | 2023-05-09 | Soft start circuit of energy storage inverter |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2008252967A (en) * | 2007-03-29 | 2008-10-16 | Matsushita Electric Ind Co Ltd | Motor control device |
| CN112653101A (en) * | 2021-01-05 | 2021-04-13 | 江苏固德威电源科技股份有限公司 | Protection device applied to direct current bus system |
| CN113992111A (en) * | 2021-10-22 | 2022-01-28 | 珠海格力电器股份有限公司 | Dynamic braking circuit of servo driver and servo driver |
| US20220131458A1 (en) * | 2020-10-23 | 2022-04-28 | Delta Electronics (Shanghai) Co.,Ltd. | Auxiliary power supply device for inverter, inverter, and method for starting the same |
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2023
- 2023-05-09 CN CN202310528663.XA patent/CN116545287A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008252967A (en) * | 2007-03-29 | 2008-10-16 | Matsushita Electric Ind Co Ltd | Motor control device |
| US20220131458A1 (en) * | 2020-10-23 | 2022-04-28 | Delta Electronics (Shanghai) Co.,Ltd. | Auxiliary power supply device for inverter, inverter, and method for starting the same |
| CN112653101A (en) * | 2021-01-05 | 2021-04-13 | 江苏固德威电源科技股份有限公司 | Protection device applied to direct current bus system |
| CN113992111A (en) * | 2021-10-22 | 2022-01-28 | 珠海格力电器股份有限公司 | Dynamic braking circuit of servo driver and servo driver |
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