WO2023024848A1

WO2023024848A1 - Multi-level capacitive pre-charging circuit and power supply device

Info

Publication number: WO2023024848A1
Application number: PCT/CN2022/109792
Authority: WO
Inventors: 崔玉龙; 周建平; 林国仙; 王恰; 张伟; 樊珊珊; 董秀锋
Original assignee: 中兴通讯股份有限公司
Priority date: 2021-08-24
Filing date: 2022-08-02
Publication date: 2023-03-02
Also published as: CN115720049A

Abstract

A multi-level capacitive pre-charging circuit and a power supply device. When an input alternating current power supply (500) is connected, and a first switching device and a second switching device are in an off state, the input alternating current power supply (500) can pre-charge a flying capacitor by means of a circuit that is formed by connecting an inductor, the first switching device, the flying capacitor, a second auxiliary diode, an auxiliary resistor, an auxiliary capacitor, a second rectification device, and the input alternating current power supply (500) in series, and can also pre-charge the flying capacitor by means of a circuit formed by connecting the inductor, the input alternating current power supply (500), a first rectification device, the auxiliary capacitor, the auxiliary resistor, a first auxiliary diode, the flying capacitor, and the second switching device in series.

Description

Multilevel Capacitor Precharge Circuits and Power Supplies

Cross References to Related Applications

This application is based on a Chinese patent application with application number 202110972431.4 and a filing date of August 24, 2021, and claims the priority of this Chinese patent application. The entire content of this Chinese patent application is hereby incorporated by reference into this application.

technical field

The embodiments of the present application relate to but are not limited to the technical field of charging, and in particular relate to a multi-level capacitor precharging circuit and a power supply device.

Background technique

With the development and application of 5G technology, the demand for communication power is increasing rapidly. At the same time, the new market puts forward new requirements for various performance indicators of communication power supplies. Low cost, high efficiency, and high power density have become the inevitable trend of power supply development.

Compared with other AC (Alternating Current, alternating current)/DC (Direct Current, direct current) conversion topologies, the multi-level AC/DC conversion topology has the following advantages: Under the same ripple requirement, the inductor volume can be reduced and the The power density of the system; under the same output voltage, the multi-level AC/DC conversion topology can reduce the voltage stress of the switch tube, and the switch device with low withstand voltage can be selected to reduce the on-resistance.

However, when some multilevel converters, such as the flying capacitor type multilevel converter, start to work, the flying capacitor needs to be precharged to ensure that the voltage across the semiconductor switching tube cannot exceed the limit value. However, when the system is first powered on, the flying capacitor does not have a charging circuit, so the BUS (bus) voltage will be charged to the maximum input voltage, and the voltage on the flying capacitor is 0. If this state is maintained until the converter starts to work , that is, the switching tube starts to act, which will cause the voltage stress of the switching tube to exceed the standard and be damaged.

Therefore, in order to ensure that the switch tube stress remains within a reasonable range when the converter is working, it is necessary to precharge the capacitors of the multilevel converter, and the existing precharging schemes are mostly active precharging schemes, usually An additional auxiliary source is required to complete the pre-charging of the capacitor before the system is powered on, or an additional switch is added to the power circuit. The initial state of the switch is off, and an additional auxiliary source or auxiliary charging circuit is used to charge the capacitor until the capacitor reaches Design value, the switch is closed, and the converter starts to work. The above two solutions require an additional auxiliary source for power supply, which increases the complexity of the system, and second, add switches in the power loop, which will bring additional losses when the converter is working normally.

Contents of the invention

The following is an overview of the topics described in detail in this article. This summary is not intended to limit the scope of the claims.

The embodiment of the present application provides a multi-level capacitor pre-charging circuit and power supply equipment, which can complete the capacitor pre-charging circuit before the switching device starts to work without the need for additional auxiliary source power supply, and without adding additional switches in the power circuit. Charge.

In the first aspect, the embodiment of the present application provides a multi-level capacitor precharging circuit, including: a rectification module, including a first rectification device and a second rectification device; a switched capacitor module, including an inductor, a flying capacitor, a plurality of A first switching device connected in series and a plurality of second switching devices connected in series in sequence, the inductor, the plurality of first switching devices, the first rectifying device and the input AC power supply are connected in series in sequence, the inductor, A plurality of the second switching devices, the second rectifying device and the input AC power supply are connected in series in sequence, one end of the flying capacitor is connected to a common point between two adjacent first switching devices, The other end is connected to a common point between two adjacent second switching devices; the auxiliary charging module includes a first auxiliary diode, a second auxiliary diode, an auxiliary resistor and a plurality of auxiliary capacitors, the inductor, the The first switching device, the flying capacitor, the second auxiliary diode, the auxiliary resistor, the auxiliary capacitor, the second rectifier device and the input AC power supply are sequentially connected in series to form a loop; the inductor , the input AC power supply, the first rectifying device, the auxiliary capacitor, the auxiliary resistor, the first auxiliary diode, the flying capacitor and the second switching device are sequentially connected in series to form a loop.

In the second aspect, the embodiment of the present application further provides a power supply device, including the multi-level capacitor precharging circuit as described in the first aspect.

The embodiment of the present application includes: the multi-level capacitor precharging circuit of the embodiment of the present application includes a rectification module, a switched capacitor module and an auxiliary charging module, the rectification module includes a first rectification device and a second rectification device; the switched capacitor module includes an inductor, A flying capacitor, a plurality of first switching devices connected in series in series and a plurality of second switching devices connected in series in sequence, an inductor, a plurality of first switching devices, a first rectifier device and an input AC power supply connected in series in sequence, the inductor, a plurality of The second switching device, the second rectifying device and the input AC power are connected in series in sequence, one end of the flying capacitor is connected to a common point between two adjacent first switching devices, and the other end is connected to two adjacent second switches The common point between devices; the auxiliary charging module includes a first auxiliary diode, a second auxiliary diode, an auxiliary resistor and a plurality of auxiliary capacitors, an inductor, a first switching device, a flying capacitor, a second auxiliary diode, an auxiliary resistor, an auxiliary The capacitor, the second rectifying device and the input AC power supply are connected in series to form a loop; the inductor, the input AC power supply, the first rectifying device, the auxiliary capacitor, the auxiliary resistor, the first auxiliary diode, the flying capacitor and the second switching device are connected in series to form a loop . According to the technical solution of the embodiment of the present application, when the input AC power is connected, before the first switching device and the second switching device work, that is, when the first switching device and the second switching device are in the off state, the input AC power can In a certain half cycle, the flying capacitor is precharged through the loop formed by the inductor, the first switching device, the flying capacitor, the second auxiliary diode, the auxiliary resistor, the auxiliary capacitor, the second rectifier device and the input AC power in series. , at the same time, in the other half cycle, the input AC power supply can also be formed by serially connecting the inductor, the input AC power supply, the first rectifier device, the auxiliary capacitor, the auxiliary resistor, the first auxiliary diode, the flying capacitor and the second switching device loop to precharge the flying capacitor.

Additional features and advantages of the application will be set forth in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Description of drawings

The accompanying drawings are used to provide an understanding of the technical solution of the present application, and constitute a part of the description, and are used together with the embodiments of the present application to explain the technical solution of the present application, and do not constitute a limitation to the technical solution of the present application.

Fig. 1 is a schematic diagram of the voltage stress of the switching tube of the flying capacitor type multilevel converter when the flying capacitor voltage is V _o /2;

Fig. 2 is a schematic diagram of the voltage stress of the switching tube of the flying capacitor type multilevel converter when the flying capacitor voltage is 0;

Fig. 3 is a circuit block diagram of a multilevel capacitor precharging circuit provided by an embodiment of the present application;

FIG. 4 is a circuit topology diagram of a multi-level capacitor precharging circuit provided by an embodiment of the present application;

FIG. 5 is a circuit topology diagram of a three-level capacitor precharging circuit provided by an embodiment of the present application;

FIG. 6 is a circuit topology diagram of a four-level capacitor precharging circuit provided by an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments described here are only used to explain the present application, not to limit the present application.

It should be noted that although the functional modules are divided in the schematic diagram of the device, and the logical sequence is shown in the flowchart, in some cases, it can be executed in a different order than the module division in the device or the flowchart in the flowchart. steps shown or described. The terms "first", "second" and the like in the specification, claims or the above drawings are used to distinguish similar objects, and not necessarily used to describe a specific order or sequence.

In some cases, with the development and application of 5G technology, the demand for communication power has increased rapidly. At the same time, the new market puts forward new requirements for various performance indicators of communication power supplies. Low cost, high efficiency, and high power density have become the inevitable trend of power supply development.

Compared with other AC/DC conversion topologies, the multi-level AC/DC conversion topology has the following advantages:

(1) Under the same ripple requirement, the volume of the inductor can be reduced and the power density of the system can be improved;

(2) Under the same output voltage, the multi-level AC/DC conversion topology can reduce the voltage stress of the switch tube, and the switch device with low withstand voltage can be selected to reduce the on-resistance.

However, when some multilevel converters, such as the flying capacitor type multilevel converter, start to work, the flying capacitor needs to be precharged to ensure that the voltage across the semiconductor switching tube cannot exceed the limit value. However, when the system is first powered on, the flying capacitor does not have a charging circuit, so the BUS voltage will be charged to the maximum input voltage, while the voltage on the flying capacitor is 0. If this state is maintained until the converter starts to work, that is, the switch If the tube starts to move, it will cause the voltage stress of the switch tube to exceed the standard and be damaged.

As shown in Figure 1, Figure 1 is a schematic diagram of the voltage stress of the switch tube when the flying capacitor voltage of the flying capacitor multilevel converter starts to work when the flying capacitor voltage is V _o /2; where C _f1 is the Capacitor, that is, the flying capacitor, when the flying capacitor is pre-charged before the converter works and reaches the design value V _o /2, when the semiconductor switch _S3 is turned on, the voltage borne by the semiconductor switch _S4 is V _o /2, under normal working conditions, the maximum platform voltage value of each semiconductor switching tube is V _o /2.

In addition, as shown in Figure 2, Figure 2 is a schematic diagram of the voltage stress of the switch tube when the flying capacitor voltage is 0 when the flying capacitor multilevel converter starts to work; the flying capacitor C _f1 starts working when the converter starts , its voltage is 0V. When the converter starts to work, the semiconductor switch _S3 is turned on. At this time, the semiconductor switch _S4 bears the entire busbar voltage V _o , and there is a risk of overvoltage breakdown.

Based on the above situation, an embodiment of the present application provides a multi-level capacitor pre-charging circuit and a power supply device, wherein the multi-level capacitor pre-charging circuit includes but is not limited to a rectifier module, a switched capacitor module and an auxiliary charging module, and the rectifier module Including but not limited to a first rectifying device and a second rectifying device; the switched capacitor module includes but not limited to an inductor, a flying capacitor, a plurality of first switching devices connected in series and a plurality of second switching devices connected in series, Inductors, multiple first switching devices, first rectifying devices, and input AC power are connected in series in sequence, inductors, multiple second switching devices, second rectifying devices, and input AC power are connected in series in sequence, and one end of the flying capacitor is connected to the phase The common point between two adjacent first switching devices, and the other end is connected to the common point between two adjacent second switching devices; the auxiliary charging module includes but is not limited to a first auxiliary diode, a second auxiliary diode , an auxiliary resistor and a plurality of auxiliary capacitors, an inductor, a first switching device, a flying capacitor, a second auxiliary diode, an auxiliary resistor, an auxiliary capacitor, a second rectifier device and an input AC power supply are connected in series to form a loop; the inductor, the input AC The power supply, the first rectifying device, the auxiliary capacitor, the auxiliary resistor, the first auxiliary diode, the flying capacitor and the second switching device are connected in series in sequence to form a loop. According to the technical solution of the embodiment of the present application, when the input AC power is connected, before the first switching device and the second switching device work, that is, when the first switching device and the second switching device are in the off state, the input AC power can In a certain half cycle, the flying capacitor is precharged through the loop formed by the inductor, the first switching device, the flying capacitor, the second auxiliary diode, the auxiliary resistor, the auxiliary capacitor, the second rectifier device and the input AC power in series. , at the same time, in the other half cycle, the input AC power supply can also be formed by serially connecting the inductor, the input AC power supply, the first rectifier device, the auxiliary capacitor, the auxiliary resistor, the first auxiliary diode, the flying capacitor and the second switching device The loop precharges the flying capacitor. Therefore, in the embodiment of the present application, when the input AC power is connected, the first switching device and the second switching device remain in the off state, and no additional auxiliary source power supply is required, and no power supply is required. By adding an extra switch to the circuit, the voltage value of the flying capacitor can be precharged to the designed voltage value before the first switching device and the second switching device work by using a simple auxiliary charging circuit. Therefore, the embodiment of the present application not only reduces It reduces the complexity of the circuit without causing additional losses.

Embodiments of the present application will be described below in conjunction with the accompanying drawings.

As shown in Figures 3 to 4, Figure 3 is a circuit block diagram of a multi-level capacitor pre-charging circuit provided by an embodiment of the present application, and Figure 4 is a circuit diagram of a multi-level capacitor pre-charging circuit provided by an embodiment of the present application Topology. The multi-level capacitor precharging circuit in the embodiment of the present application includes but is not limited to a rectifier module 100 , a switched capacitor module 200 , an auxiliary charging module 300 and a bus capacitor 400 .

The aforementioned rectification module 100 includes but is not limited to a first rectification device Q ₁ and a second rectification device Q ₂ .

In addition, the above switched capacitor module 200 includes, but is not limited to, inductor L ₁ , flying capacitors C _f1 , C _f2 , ..., C _fN-1 , and a plurality of first switching devices S ₂ and S ₄ connected in series in sequence. , ..., S _2N and multiple second switching devices S ₁ , S ₃ , ..., S _2N-1 serially connected in sequence, inductor L ₁ , multiple first switching devices S ₂ , S ₄ , ..., S _2N , The first rectifying device Q ₁ and the input AC power source 500 are connected in series sequentially, and the inductor L ₁ , multiple second switching devices S ₁ , S ₃ , ..., S _2N-1 , the second rectifying device Q ₂ and the input AC power source 500 are sequentially connected. connected in series, one end of the flying capacitor is connected to a common point between two adjacent first switching devices, and the other end is connected to a common point between two adjacent second switching devices, for example, the first One end of the flying capacitor C _f1 is connected to the common point between the first first switching device _S2 and the second first switching device _S4 , and the other end is connected to the first second switching device _S1 and the second A common point between the second switching device _S3 ; or, one end of the second flying capacitor C _f2 is connected to the second first switching device _S4 and the third first switching device _S6 between common point, and the other end is connected to the common point between the second second switching device _S3 and the third second switching device _S5 .

In addition, the aforementioned auxiliary charging module 300 includes but is not limited to first auxiliary diodes D ₂ , D ₄ , ..., D _2N- ₂ , second auxiliary diodes D ₁ , D ₃ , ..., D _2N-3 , auxiliary Resistors R ₁ , R ₂ , ..., RN _-2 , RN _-1 and a plurality of auxiliary capacitors C ₁ , C ₂ , ..., C _N-1 , C _N , inductors, first switching devices, flying capacitors , the second auxiliary diode, the auxiliary resistor, the auxiliary capacitor, the second rectification device and the input AC power supply 500 are connected in series to form a loop; the inductor, the input AC power source 500, the first rectifier device, the auxiliary capacitor, the auxiliary resistor, the first auxiliary diode, The flying capacitor and the second switching device are sequentially connected in series to form a loop.

In addition, regarding the above-mentioned bus capacitor 400, one end thereof is connected to the common point of the first rectification device _Q1 and the first auxiliary capacitor _C1 , and the other end is connected to the second rectification device _Q2 and the Nth auxiliary capacitor C _N common point.

According to the technical solution of the embodiment of the present application, when the input AC power supply 500 is connected, the first switching devices S ₂ , S ₄ , ..., S _2N and the second switching devices S ₁ , S ₃ , ..., S _2N-1 are at Before working, that is, when the first switching devices S ₂ , S ₄ , ..., S _2N and the second switching devices S ₁ , S ₃ , ..., S _2N-1 are in the off state, the input AC power supply 500 can be in a certain half cycle Internally, the flying capacitor is precharged through a loop formed in series by the inductor, the first switching device, the flying capacitor, the second auxiliary diode, the auxiliary resistor, the auxiliary capacitor, the second rectifier device and the input AC power supply 500, and at the same time, In the other half cycle, the input AC power supply 500 can also pass through the inductor, the input AC power supply 500, the first rectifier device, the auxiliary capacitor, the auxiliary resistor, the first auxiliary diode, the flying capacitor and the second switching device formed in series. The loop precharges the flying capacitor. Therefore, when the input AC power supply 500 is connected in the embodiment of the present application, the first switching devices S ₂ , S ₄ , ..., S _2N and the second switching devices S ₁ , S ₃ , ... , S _2N-1 remains in the off state, no additional auxiliary source power supply is required, and no additional switch is required in the power circuit. Using a simple auxiliary charging circuit, the first switching devices S ₂ , S ₄ , ..., Before S _2N and the second switching devices S ₁ , S ₃ , ..., S _2N-1 work, the voltage value of the flying capacitor is precharged to the designed voltage value. Therefore, the embodiment of the present application not only reduces the complexity of the circuit, And there will be no additional loss.

It should be noted that the above-mentioned first rectifying device Q ₁ and second rectifying device Q ₂ may be diodes, MOS (Metal Oxide Semiconductor, metal oxide semiconductor) tubes, IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar type transistor) or TVS tube (Transient Voltage Suppressor, transient diode).

In addition, it should be noted that, regarding the above-mentioned first switching devices S ₂ , S ₄ , ..., S _2N and second switching devices S ₁ , S ₃ , ..., S _2N-1 , they may be a single switching tube, or, It can also be formed by connecting multiple switching tubes in parallel or in series.

It can be understood that, with regard to the above switch tube, it may be a MOS tube, an IGBT or a TVS tube.

In addition, as shown in FIG. 4, the number of the first switching devices S ₂ , S ₄ , ..., S _2N and the second switching devices S ₁ , S ₃ , ..., S _2N-1 are all N, and the flying capacitor C The number of _f1 , C _f2 , ..., C _fN-1 is N-1; the common point between the i-th first switching device and the i+1-th first switching device is connected to the i-th second switching device and An i-th flying capacitor is connected in parallel between common points between the (i+1)th second switching devices, wherein, N is a positive integer greater than or equal to 2, and i is a positive integer smaller than N.

In addition, as shown in Figure 4, the first auxiliary diodes D ₂ , D ₄ , ..., D _2N-2 , the second auxiliary diodes D ₁ , D ₃ , ..., D _2N- ₃ and auxiliary resistors R ₁ , R ₂ , The number of ..., R _N-2 , and R _N-1 is N-1, the number of auxiliary capacitors C ₁ , C ₂ , ..., C _N-1 , and C _N is N, and the N auxiliary capacitors C ₁ , C ₂ ,..., C _N-1 , C _N are connected in series in sequence; the common point between the i-th auxiliary capacitor and the i+1-th auxiliary capacitor is connected to one end of the i-th auxiliary resistor, and the other end of the i-th auxiliary resistor One end is connected with the Ni-th first auxiliary diode and the i-th second auxiliary diode.

In addition, as shown in FIG. 4, the inductor, the first to i-th first switching devices, the i-th flying capacitor, the i-th second auxiliary diode, the i-th auxiliary resistor, the i+1-th to The Nth auxiliary capacitor, the second rectifying device and the input AC power are connected in series in sequence to form a loop.

In addition, as shown in Figure 4, the inductor, the input AC power supply, the first rectifier, the first to N-ith auxiliary capacitors, the N-ith auxiliary resistor, the i-th first auxiliary diode, and the i-th flying capacitor , the i-th to the first second switching devices are sequentially connected in series to form a loop.

In addition, as shown in Figure 4, it also includes N voltage stabilizing devices D _W1 , D _W2 , ..., D _W(N-1) , D _WN , and N voltage stabilizing devices D _W1 , D _W2 , ..., D _{W( N-1)} , D _WN are connected in series in sequence, one end of the first voltage stabilizing device D _W1 is connected to the common point of the first rectifying device Q ₁ and the first auxiliary capacitor C ₁ , one end of the Nth voltage stabilizing device D _WN connected to the common point of the second rectifying device Q ₂ and the Nth auxiliary capacitor C _N ; the other end of the ith auxiliary resistor is also connected to the common point of the i'th voltage stabilizing device and the i+1th voltage stabilizing device.

As shown in FIG. 4 , the switched capacitor module 200 includes one or more inductors L ₁ , N-1 flying capacitors C _f1 , C _f2 , . . . , C _fN-1 and 2N switching devices that need to be precharged, Wherein, the 2N switching devices include N first switching devices S ₂ , S ₄ , ..., S _2N and N second switching devices S ₁ , S ₃ , ..., S _2N-1 . The input AC power supply AC is connected to the input end of the rectifier module 100, the node where the output of the rectifier module 100 is connected to the positive end of the busbar capacitor 400 is marked as a positive node, and the output of the rectifier module 100 is connected to the negative end of the busbar capacitor 400 is marked as is the ground node; one end of the input AC power supply AC is connected to the first end of the inductor L ₁ , and the second end of the inductor L ₁ is called an intermediate node; the second switching devices S ₁ , S ₃ ,..., S _{2N- 1} is sequentially connected in series between the middle node and the ground node, where the first pole of S ₁ is connected to the middle node, the second pole of S _2N-1 is connected to the ground node; the second pole of S ₁ is connected to the first pole of S ₃ connected, the connected point is marked as switch node 1; the second pole of S ₃ is connected to the first pole of S ₅ , and the connected point is marked as switch node 3; and so on, the second pole of S _2N-3 is connected to S _2N-1 The connected point is marked as switch node 2N-3; the first switching devices S ₂ , S ₄ , ..., S _2N are sequentially connected in series between the middle node and the positive node, where the second pole of S ₂ is connected to The middle node is connected, the first pole of _S2 is connected with the second pole of _S4 , and the connected point is marked as switch node 2; the first pole of _S4 is connected with the second pole of _S6 , and the connected point is marked as switch node 4. By analogy, the first pole of S _2N-2 is connected to the second pole of S _2N , and the connected node is marked as switch node 2N-2; the first pole of S _2N is connected to the positive node. The first end of the first flying capacitor C _f1 that needs to be precharged is connected to the switch node 1, and the second end is connected to the switch node 2; the first end of the second flying capacitor C _f2 that needs to be precharged is connected to the switch node 3, the second end is connected to the switch node 4; and so on, the first end of the N-1th flying capacitor C _fN-1 that needs to be precharged is connected to the switch node 2N-3, and the second end is connected to the switch node 2N -2 connected.

The auxiliary charging module includes 2(N-1) auxiliary diodes, N auxiliary capacitors C ₁ , C ₂ , ..., C _N-1 , C _N , N voltage stabilizing devices D _W1 , D _W2 , ..., D _{W( N-1)} , D _WN and N-1 auxiliary resistors R ₁ , R ₂ , ..., R _N-2 , R _N-1 , wherein 2(N-1) auxiliary diodes include N-1 first Auxiliary diodes D ₂ , D ₄ , . . . , D _2N-2 and N-1 second auxiliary diodes D ₁ , D ₃ , . . . , D _2N- ₃ . The first end of the first auxiliary capacitor _C1 is connected to the positive node, the second end of the first auxiliary capacitor _C1 is connected to the first end of the second auxiliary capacitor _C2 , and the connected node is capacitor node 1; The second end of the second auxiliary capacitor C ₂ is connected to the first end of the third auxiliary capacitor C ₃ , and the connected node is the capacitor node 2, and so on, the second end of the N-1th auxiliary capacitor C _N-1 The end is connected to the first end of the Nth auxiliary capacitor C _N , and the connected node is the capacitor node N-1, and the second end of the Nth auxiliary capacitor C _N is connected to the ground node; the first voltage stabilizing device D _W1 The first pole is connected to the positive node, the second pole of the first voltage stabilizing device D _W1 is connected to the first pole of the second voltage stabilizing device D _W2 , the connected node is voltage stabilizing node 1, and the second voltage stabilizing device The second pole of D _W2 is connected to the first pole of the third voltage stabilizing device D _W3 , and the connected node is voltage stabilizing node 2, and so on, the N-1th voltage stabilizing device D _W(N-1) The second pole is connected to the first pole of the Nth voltage stabilizing device D _WN , and the connected node is the voltage stabilizing node N-1, and the second pole of the Nth voltage stabilizing device D _WN is connected to the ground node; the first auxiliary The first end of the resistor _R1 is connected to the capacitor node 1, the second end of the first auxiliary resistor _R1 is connected to the voltage regulator node 1, the first end of the auxiliary resistor _R2 is connected to the capacitor node 1, and the auxiliary resistor _R2 ’s The second end is connected to the voltage regulator node 2, and so on, the first end of the N-1th auxiliary resistor R _N-1 is connected to the capacitor node N-1, and the first end of the N-1th auxiliary resistor R _N-1 The two terminals are connected to the voltage stabilizing node N-1. The first pole of the second auxiliary diode _D1 is connected to the first end of the first flying capacitor _Cf1 , the second pole of the second auxiliary diode _D1 is connected to the second pole of the first voltage stabilizing device _DW1 , The first pole of the second auxiliary diode _D3 is connected to the first end of the second flying capacitor C _f2 , and the second pole of the second auxiliary diode _D3 is connected to the second pole of the second voltage stabilizing device D _W2 , and so on, the first pole of the second auxiliary diode D _2N-3 is connected to the first end of the N-1th flying capacitor C _f(N-1) , and the second pole of the second auxiliary diode D _2N-3 The pole is connected to the second pole of the N-1th voltage stabilizing device D _{W (N-1)} ; the first pole of the first auxiliary diode _D2 is connected to the N-1th voltage stabilizing device D _{W (N-1)} The second pole is connected, the second pole of the first auxiliary diode _D2 is connected to the second end of the first flying capacitor C _f1 , the first pole of the first auxiliary diode _D4 is connected to the N-2th voltage stabilizing device D The second pole of _W(N-2) is connected, the second pole of the first auxiliary diode D ₄ is connected with the second end of the second flying capacitor C _f2 , and so on, the first auxiliary diode D _2N- ₂ The first pole is connected to the second pole of the first voltage stabilizing device D _W1 , the second pole of the first auxiliary diode D _2(N-1) is connected to the N-1th flying capacitor C _f(N-1) The second end is connected.

When the input AC power is connected, that is, when the input AC power is powered on, the voltage is in the positive half cycle of the AC, and the current passes through the inductor L ₁ , the first switching device S ₂ , the flying capacitor C _f1 to be charged, the diode D ₁ , The auxiliary resistor R ₁ and the auxiliary capacitors C ₂ , C ₃ , . . . , C _N charge the flying capacitor C _f1 . By analogy, the current flows through the inductor L ₁ , the first switching devices S ₂ , S ₄ , ..., S _2N-2 , the flying capacitor C _fN-1 to be charged, the second auxiliary diode D _2N-3 , and the auxiliary resistor R _N-1 , auxiliary capacitor C _N , charge the flying capacitor C _fN-1 ; when the input is in the negative half cycle of AC, the current passes through the rectifier module, then through auxiliary capacitors C ₁ , C ₂ , ..., C _N-1 , auxiliary The resistor R _N-1 , the first auxiliary diode D ₂ , the flying capacitor C _f1 to be charged, the second switching device S ₁ , and the inductor L ₁ charge the flying capacitor C _f1 . By analogy, after the current passes through the rectifier module, it passes through the auxiliary capacitor C ₁ , the auxiliary resistor R ₁ , the first auxiliary diode D _2N-2 , the flying capacitor C _f(N-1) to be charged, and the second switching device S _{2N- 3} , ..., S ₁ , and inductor L ₁ charge the capacitor C _f(N-1) . Generally speaking, alternating positive and negative half-cycle charging is often required to charge the flying capacitor to the design value.

It should be noted that the first pole, the second pole, the first end, and the second end of the device are only distinguished in description, and have no meaning in importance or order.

In addition, as shown in FIG. 5 , FIG. 5 is a circuit topology diagram of a three-level capacitor precharging circuit provided by an embodiment of the present application. The input AC power supply AC is connected to the full-bridge rectifier module. The positive output terminal of the rectifier module, that is, the negative pole of the first rectifier device _Q1 , is connected to the positive terminal of the bus capacitor C _o , and the negative output terminal of the rectifier module is the terminal of the second rectifier device _Q2 . The positive pole is connected to the negative terminal of the bus capacitor C _o , one terminal of the input AC power supply AC is connected to one terminal of the inductor _L1 , and the other terminal of the inductor _L1 is connected to the first pole of the second switching device _S1 and the first switching device _S2 The second pole of the second switching device S ₁ is connected to the flying capacitor C _f1 between the second pole of the second switching device S 1 and the first pole of the first switching device S ₂ , and the first pole of the first switching device S ₂ is connected to the first switching device The second pole of _S4 and the first pole of the first switching device _S4 are connected to the positive terminal of the bus capacitor C _o ; the second pole of the second switching device _S1 is connected to the first pole of the second switching device _S3 , and the second The second pole of the switching device S ₃ is connected to the negative terminal of the bus capacitor C _o ; the auxiliary charging module is composed of the second auxiliary diode D ₁ , the first auxiliary diode D ₂ , voltage stabilizing devices D _w1 , D _w2 , auxiliary resistor R ₁ , Composed of auxiliary capacitors C ₁ and C ₂ ; auxiliary capacitors C ₁ and C ₂ are connected in parallel with the bus capacitor C _o after being connected in series; the voltage stabilizing devices D _w1 and D _w2 are connected in parallel with the bus capacitor C _o after being connected in series; the first voltage stabilizing device D _w1 The pole is connected to the first end of the auxiliary resistor R ₁ , and the second end of the auxiliary resistor R ₁ is connected to the midpoint of the series connection of the auxiliary capacitors C ₁ and C ₂ . The first pole of the second auxiliary diode _D1 is connected to the first end of the flying capacitor C _f1 , the second pole of the second auxiliary diode _D1 is connected to the first end of the auxiliary resistor _R1 , and the second end of the first auxiliary diode _D2 The _first pole of the first auxiliary diode _D2 is connected to the first end of the auxiliary resistor _R1 .

In this embodiment, it is necessary to charge the voltage of the flying capacitor C _f1 to 1/2 of the voltage value of the bus capacitor C _o . When the input AC power supply is powered on and the AC input is in the positive half cycle, the current flows through the inductor L ₁ , The first switching device S ₂ , the flying capacitor C _f1 , the second auxiliary diode D ₁ , the auxiliary resistor R ₁ , the auxiliary capacitor C ₂ , and the second rectifier Q ₂ form a loop to charge the flying capacitor C _f1 . After charging for a period of time , the voltage is stable, at this time the voltage of the flying capacitor C _f1 is less than 1/2 of the output voltage; when the AC input is in the negative half cycle, the current passes through the first rectifier device Q ₁ , the auxiliary capacitor C ₁ , the auxiliary resistor R ₁ , the first auxiliary The diode D ₂ , the flying capacitor C _f1 , the second switching device S ₁ , and the inductor L ₁ form a loop to charge the flying capacitor C _f1 again, and the voltage of the flying capacitor rises further; after several cycles of alternating positive and negative half cycles, The voltage value of the flying capacitor C _f1 is stable at 1/2 of the voltage value of the bus capacitor C _o .

In addition, as shown in FIG. 6 , FIG. 6 is a circuit topology diagram of a four-level capacitor precharging circuit provided by an embodiment of the present application. In this embodiment, the flying capacitor C _f1 needs to be precharged to 1/3 of the voltage value of the bus capacitor C _o , and the flying capacitor C _f2 is precharged to 2/3 of the voltage value of the bus capacitor C _o .

The input AC power supply AC is connected to the full-bridge rectifier module. The positive output terminal of the rectifier module, that is, the negative pole of the first rectifier device _Q1 , is connected to the positive terminal of the bus capacitor C _o , and the negative output terminal of the rectifier module is the terminal of the second rectifier device _Q2 . The positive pole is connected to the negative terminal of the bus capacitor C _o , one terminal of the input AC power supply AC is connected to the first terminal of the inductor _L1 , and the second terminal of the inductor _L1 is connected to the first pole and the first pole of the second switching device _S1 . The second pole of the switching device _S2 is connected, the first pole of the first switching device _S2 is connected to the second pole of the first switching device _S4 , the first pole of the first switching device _S4 is connected to the first pole of the first switching device _S6 The second pole of the first switching device _S6 is connected to the positive end of the bus capacitor C _o ; the second pole of the second switching device _S1 is connected to the first pole of the second switching device _S3 , and the second The second pole of the switching device _S3 is connected to the first pole of the second switching device _S5 , and the second pole of the second switching device _S5 is connected to the negative terminal of the bus capacitor C _o . In order to achieve the charging effect of precharging the flying capacitor C _f1 to 1/3 of the voltage value of the bus capacitor C _o and precharging the flying capacitor C _f2 to 2/3 of the voltage value of the bus capacitor C _o , the auxiliary charging module uses 3 Auxiliary capacitors C ₁ , C ₂ , and C ₃ are connected in parallel with the bus capacitor C _o after being connected in series. The first end of the auxiliary capacitor C ₁ is connected to the positive end of the bus capacitor C _o , and the second end of the auxiliary capacitor C ₁ is connected to the auxiliary capacitor C ₂ The first end of the auxiliary capacitor _C2 is connected to the first end of the auxiliary capacitor _C3 , and the second end of the auxiliary capacitor _C3 is connected to the negative end of the bus capacitor C _o . The first pole of the voltage stabilizing device _Dw1 is connected to the positive end of the bus capacitor C _o , the second pole of the voltage stabilizing device _Dw1 is connected to the first pole of the voltage stabilizing device _Dw2 , and the second pole of the voltage stabilizing device _Dw2 is connected to The first pole of the voltage stabilizing device _Dw3 is connected, and the second pole of the voltage stabilizing device _Dw3 is connected to the negative terminal of the bus capacitor C _o . The first end of the auxiliary resistor _R1 is connected to the second pole of the voltage stabilizing device _Dw1 , the second end of the auxiliary resistor _R1 is connected to the second end of the auxiliary capacitor _C1 , and the first end of the auxiliary resistor _R2 is connected to the voltage regulator The second pole of the device D _w2 is connected, the second end of the auxiliary resistor R2 is connected with the second end of the auxiliary capacitor _C2 ; the first pole of the second auxiliary diode _D1 is connected with the first end of the flying capacitor C _f1 , and the second end of the auxiliary capacitor C The second pole of the second auxiliary diode D ₁ is connected to the first end of the auxiliary resistor R ₁ ; the second pole of the first auxiliary diode D ₂ is connected to the second end of the flying capacitor C f1, and the second pole of the first auxiliary diode D ₂ is connected to the second end of the flying capacitor C _f1 One pole is connected to the first end of the auxiliary resistor _R2 ; the first pole of the second auxiliary diode D3 is connected to the first end of the flying capacitor C _f2 , and the second pole of the second auxiliary diode _D3 is connected to the first end of the auxiliary resistor _R2 The first end is connected; the second pole of the first auxiliary diode _D4 is connected to the second end of the flying capacitor _Cf2 , and the first pole of the first auxiliary diode _D2 is connected to the first end of the auxiliary resistor _R1 .

When the input AC power supply is powered on and the input is in the positive half cycle of the AC, the charging circuit of the flying capacitor C _f1 is: inductor L ₁ , the first switching device S ₂ , the flying capacitor C _f1 , and the second auxiliary diode D ₁ , auxiliary resistor R ₁ , auxiliary capacitor C ₂ , auxiliary capacitor C ₃ , and second rectifier device Q ₂ ; the charging circuit of flying capacitor C _f2 is: inductor L ₁ , first switching device S ₂ , first switching device S _4. The flying capacitor C _f2 , the second auxiliary diode D ₃ , the auxiliary resistor R ₂ , the auxiliary capacitor C ₃ , and the second rectifying device Q ₂ . When the input is in the negative half cycle of AC, the charging circuit of the flying capacitor C _f1 is: the first rectifier device Q ₁ , the auxiliary capacitor C ₁ , the auxiliary capacitor C ₂ , the auxiliary resistor R ₂ , the first auxiliary diode D ₂ , and the flying capacitor C _f1 , the second switching device S ₁ , the inductor L ₁ ; the charging circuit of the flying capacitor C _f2 is: the first rectifying device Q1, the auxiliary capacitor C1, the auxiliary resistor R1, the first auxiliary diode D4, the flying capacitor C _f2 , The second switching device S ₃ , the second switching device S ₁ , and the inductor L ₁ . After several cycles of positive and negative half-cycle alternating charging, the voltage of the flying capacitor C _f1 is stabilized at the set value V ₁ , and the voltage of the flying capacitor C _f2 is stabilized at the set value V ₂ .

Based on the multilevel capacitor precharging circuit shown in FIGS. 3 to 6 above, an embodiment of the present application further provides a power supply device, including but not limited to the multilevel capacitor precharging circuit shown in FIGS. 3 to 6 above.

It should be noted that, for the implementation manner and technical effect of the power supply device in the embodiment of the present application, reference may be made to the implementation manner and technical effect of the multi-level capacitor precharging circuit described above.

Therefore, in the embodiment of the present application, when the input AC power is connected, the first switching device and the second switching device remain in the off state, no additional auxiliary source is required for power supply, and no additional switch is required in the power circuit. The charging circuit can precharge the voltage value of the flying capacitor to the designed voltage value before the first switching device and the second switching device work. Therefore, the embodiment of the present application not only reduces the complexity of the circuit, but also does not cause additional losses.

The above is a specific description of the embodiments of the present application, but the present application is not limited to the above-mentioned embodiments, and those skilled in the art can also make various equivalent deformations or replacements without violating the sharing conditions of the spirit of the present application. Equivalent modifications or replacements are all within the scope defined by the claims of the present application.

Claims

A multilevel capacitor precharge circuit, comprising:

A rectification module, including a first rectification device and a second rectification device;

A switched capacitor module, including an inductor, a flying capacitor, a plurality of first switching devices connected in series and a plurality of second switching devices connected in series, the inductor, a plurality of the first switching devices, the first The rectifying device and the input AC power are connected in series in sequence, the inductor, the plurality of second switching devices, the second rectifying device and the input AC power are connected in series in sequence, and one end of the flying capacitor is connected to the adjacent The other end of the common point between the two first switching devices is connected to the common point between the two adjacent second switching devices; and

The auxiliary charging module includes a first auxiliary diode, a second auxiliary diode, an auxiliary resistor and a plurality of auxiliary capacitors, the inductor, the first switching device, the flying capacitor, the second auxiliary diode, the The auxiliary resistance, the auxiliary capacitor, the second rectifying device and the input AC power supply are sequentially connected in series to form a loop; the inductor, the input AC power source, the first rectifying device, the auxiliary capacitor, the The auxiliary resistor, the first auxiliary diode, the flying capacitor and the second switching device are sequentially connected in series to form a loop.
The multi-level capacitor precharging circuit according to claim 1, wherein: the number of the first switching device and the number of the second switching device are N, and the number of the flying capacitor is N-1; The common point between the i-th first switching device and the i+1-th first switching device and between the i-th second switching device and the i+1-th second switching device The i-th flying capacitor is connected in parallel between the common points, wherein, the N is a positive integer greater than or equal to 2, and the i is a positive integer smaller than the N.
The multi-level capacitor precharging circuit according to claim 2, wherein: the number of the first auxiliary diode, the second auxiliary diode and the auxiliary resistor is N-1, and the number of the auxiliary capacitor is The N auxiliary capacitors are connected in series in sequence; the common point between the i-th auxiliary capacitor and the i+1-th auxiliary capacitor is connected to one end of the i-th auxiliary resistor, and the i-th auxiliary capacitor is connected to one end of the i-th auxiliary resistor. The other end of the auxiliary resistor is connected to the N-i th first auxiliary diode and the i th second auxiliary diode.
The multilevel capacitor precharging circuit according to claim 3, wherein:

The inductor, the first to i-th first switching device, the i-th flying capacitor, the i-th second auxiliary diode, the i-th auxiliary resistor, the i+1-th The first to Nth auxiliary capacitors, the second rectifying device and the input AC power supply are sequentially connected in series to form a loop;

The inductor, the input AC power supply, the first rectifying device, the first to N-ith auxiliary capacitors, the N-ith auxiliary resistor, the ith first auxiliary diode, the ith The flying capacitors and the i-th to first second switching devices are connected in series in sequence to form a loop.
The multi-level capacitor precharging circuit according to claim 3 or 4, further comprising N voltage stabilizing devices, the N voltage stabilizing devices are connected in series in sequence, and one end of the first voltage stabilizing device is connected to the first voltage stabilizing device A common point of a rectifying device and the first auxiliary capacitor, one end of the Nth voltage stabilizing device is connected to the common point of the second rectifying device and the Nth auxiliary capacitor; the ith said The other end of the auxiliary resistor is also connected to a common point of the i-th voltage stabilizing device and the (i+1)-th voltage stabilizing device.
The multi-level capacitor precharging circuit according to claim 1, further comprising a bus capacitor, one end of the bus capacitor is connected to the common point of the first rectifier device and the first auxiliary capacitor, and the other end is connected to A common point of the second rectifying device and the Nth auxiliary capacitor.
The multi-level capacitor precharging circuit according to any one of claims 1 to 4 and 6, wherein the first rectifying device and the second rectifying device are one of the following: diodes, or MOS transistors, or IGBT, or TVS tube.
The multi-level capacitor precharging circuit according to any one of claims 1 to 4 and 6, wherein the first switch device and the second switch device are a single switch tube, or the first switch The device and the second switching device are formed by connecting multiple switching tubes in parallel or in series.
The multi-level capacitor precharging circuit according to claim 8, wherein the switch tube is one of the following: MOS tube, or IGBT, or TVS tube.
A power supply device, comprising the multi-level capacitor precharging circuit according to any one of claims 1-9.