WO2014206244A1

WO2014206244A1 - High voltage circuit with automatic voltage limiting power switch device serially connected therein

Info

Publication number: WO2014206244A1
Application number: PCT/CN2014/080365
Authority: WO
Inventors: 王达开; 黄电勋
Original assignee: Wang Dakai; Huang Dianxun
Priority date: 2013-06-28
Filing date: 2014-06-20
Publication date: 2014-12-31
Also published as: CN103312138A; CN103312138B

Abstract

A high voltage circuit with an automatic voltage limiting power switch device serially connected therein comprises a branch with a power switch device serially connected therein, a plurality of energy storage circuits P1 to Pm, a plurality of discharge diodes Dp, a plurality of junction diodes Dq, an energy concentration diode Du, and a concentration voltage limiting circuit U. A concentration voltage limiting circuit with a low voltage is used to limit a voltage of each energy storage capacitor C, so that safe voltage limiting is implemented for each power switch device. The circuit solves the problem that serial connection, for use, of power switch devices with a withstand voltage of 3300 V or above is limited due to low withstand voltages of ordinary small packaged clamp diodes such as T0220, T0247, and the like in the prior art. A reverse breakdown voltage of a clamp diode of the circuit can be reduced by several times while a reverse recovery current is also decreased, so that the clamp diode works in a safe work area, thereby greatly improving the system reliability.

Description

Automatic voltage limiting power switching device series high voltage circuit

Technical field

The present invention relates to a voltage limiting circuit, and more particularly to a high voltage circuit for use in series with an automatic voltage limiting power switching device. Background technique

The PWM switching power switching device series circuit has great application prospects in the field of high voltage inverter and DC flexible transmission. At present, insulated gate bipolar transistor (IGBT) series bridge arms have been applied to 3KV, 10KV high voltage inverters.

Due to the low withstand voltage of current power switching devices, such as the insulation voltage bipolar transistor (IGBT) with a withstand voltage of 1200V, 1700V, 3300V, in high-voltage circuits such as 10KV, 500KV circuits, several power switching devices are required. Work in tandem to solve the withstand voltage problem. Due to the discreteness of the parameters of the power switching device, the difference in the external environment, the parameter difference of the additional circuit, etc., each power switching device in the series circuit is subjected to dynamic voltage inconsistency during the turn-on process and the turn-off process. The power switching device that is turned on after the turn-on process, and the voltage that the power switch device that is turned off first during the turn-off process is too high, and is damaged beyond the voltage limit value of the power switch device.

Therefore, when the power switching device is used in series, it is necessary to take corresponding measures to limit the voltage across it to a safe working voltage range, and generally limit its working withstand voltage to within 70% of the maximum withstand voltage.

For the series application of power switching devices, there are various technical methods to solve them. Among them, the passive buffer circuit defines the voltage method and is widely used. For example, a Chinese patent "a series-type power switch bridge arm capable of automatic voltage equalization" (Application No. 01108712. 9) discloses a dynamic and static voltage equalizing circuit composed of a passive device buffer device connected in parallel at both ends of a power switching device. , the circuit form is shown in Figure 1. Another example is a PCT patent application "Power Switching Device Series Voltage Limiting Circuit" (International Application No. PCT/CN2010/078206), which discloses an automatic voltage limiting by first adjusting the energy storage of a capacitor connected in parallel across the power switching device. The power switching device is connected in series, and the circuit form is shown in Figure 2.

The drawbacks of these two technologies are: First, the clamping diode withstand voltage of the passive snubber circuit is matched to the withstand voltage rating of the corresponding power switching device. The common Τ0220, Τ0247 and other packaged diodes, the operating current can meet the circuit requirements, but the withstand voltage value is generally below 2000V. Resulting in the work used in series The voltage level of the switching device is limited to 1200V, 1700V and other voltage levels. If these two technologies are not suitable for series connection of IGBTs of 3300V or higher. Second, the clamp diode of the passive snubber circuit enters the voltage at the reverse cutoff, reaching the high voltage corresponding to the cutoff of the power switching device, and the reverse current is large, so that the diode is easily broken down due to exceeding the safe working area. . Third, the voltage limiting range of the voltage limiting circuit is up to several thousand volts, which makes the voltage sampling circuit complicated and the sampling accuracy is reduced. Fourth, the voltage of the remaining components is too high and the safety spacing is large. Summary of the invention

The technical problem solved by the invention is: constructing a series high voltage circuit of a power limiting device with automatic voltage limiting, which overcomes the limitation of the voltage withstand voltage of the prior art power switching device, the clamping diode is easily damaged, and the power switching device limits the voltage deviation. Technical problems with high component withstand voltage requirements.

The technical solution of the present invention is: constructing a series high voltage circuit of a power limiting device with automatic voltage limiting, comprising a series branch of a power switching device composed of a plurality of power switching devices Q1 to Qn, a concentrated voltage limiting circuit U, the power switch The device comprises a control terminal, a high-end SD and a low-end WD, wherein the power switching device series branch is connected in series in a manner that a high-end SD of one power switching device is connected to a low-end WD of another power switching device, and the concentrated voltage limiting circuit U The high voltage terminal U+ and the low voltage terminal U- are included; further comprising a plurality of energy storage circuits P1 to Pm for performing energy storage, a plurality of discharge diodes Dp, a plurality of bus diodes Dq, and an energy concentration diode Du, each of the power switches The device is coupled to the energy storage circuit, and at least one power switching device is coupled to the plurality of energy storage circuits, and the energy storage circuit includes a storage capacitor C, a static voltage equalization resistor R, and a clamp diode D, and Connecting a power storage circuit of the one power switching device or the plurality of energy storage circuits cooperating with the one power switching device, and connecting the power switch in parallel The energy storage circuit includes a storage capacitor C, a static voltage equalization resistor R, and a clamp diode D. The storage capacitor C and the static voltage equalization resistor R are connected in series with the clamp diode D to store The positive terminal of the energy capacitor C leads to the energy storage return terminal Cf, the negative terminal of the energy storage capacitor C leads to the energy storage return terminal Cr, and the energy storage circuit of the plurality of strings connected in parallel at both ends of one power switching device, each adjacent two A discharge diode Dp is connected between the energy storage return terminals Cf, and a discharge diode Dp is connected between each adjacent two energy storage return terminals Cr; the last one of the plurality of series energy storage circuits connected in parallel with the previous power switching device The capacitance of the energy circuit is connected to the cathode of the bus diode Dq, and the capacitance of the first energy storage circuit of the plurality of series energy storage circuits connected in parallel with the latter power switching device is connected to the anode of the bus diode Dq; The terminals are respectively connected to the energy concentrated diode Du and a power switching device. A further technical solution of the present invention is: in a tank circuit connected in parallel with a power switching device, the tank circuit includes a storage capacitor C, a static voltage equalizing resistor R, and a clamping diode D, the storage capacitor C. After the static voltage equalizing resistor R is connected in parallel, the energy storage return terminal Cf is connected to the cathode of the clamp diode D, and the energy storage return terminal Cr is connected to the low end WD of the power switching device, and the anode of the clamp diode is The high-end SD of the power switching device is connected. A further technical solution of the present invention is: in a tank circuit connected in parallel with a power switching device, the tank circuit includes a storage capacitor C, a static voltage equalizing resistor R, and a clamping diode D, the storage capacitor C. After the static voltage equalizing resistor R is connected in parallel, the energy storage return terminal Cf is connected to the anode of the clamp diode D, and the energy storage return terminal Cf is connected to the high end SD of the power switching device, the cathode of the clamp diode and the power switch. The low-end WD of the device. A further technical solution of the present invention is: in a plurality of energy storage circuits connected in parallel with a power switching device, the energy storage capacitor C and the static voltage equalizing resistor R of each energy storage circuit are connected in parallel, and the energy storage return end Cf and the clamp The cathode of the diode D is connected, and the energy storage return terminal Cr is connected to the anode of the clamp diode of the next tank circuit, and the anode of the clamp diode D of the first tank circuit is connected to the high-end SD of the corresponding power switch device. The energy storage return terminal Cr of the last tank circuit is connected to the lower end WD of the corresponding power switching device, the former energy storage return terminal Cf is connected to the cathode of a discharge diode Dp, and the latter energy storage return terminal Cf and the discharge The anode of the diode Dp is connected, the former energy storage return terminal Cr is connected to the cathode of the other discharge diode Dp, and the latter energy storage return terminal Cr is connected to the anode of the discharge diode Dp. A further technical solution of the present invention is: in a plurality of energy storage circuits connected in parallel with a power switching device, the energy storage capacitor C and the static voltage equalizing resistor R of each energy storage circuit are connected in parallel, and the energy storage return terminal Cr and the clamp The anode of the bit diode D is connected, the first energy storage return terminal Cf is connected to the high end SD of the corresponding power switching device, and the remaining energy storage return terminal Cf is connected to the cathode of the clamp diode of the previous tank circuit, and the last one is stored. The cathode of the clamp diode D of the energy circuit is connected to the lower end WD of the corresponding power switching device, the former energy storage return terminal Cf is connected to the cathode of a discharge diode Dp, and the latter energy storage return terminal Cf and the discharge diode Dp The anode is connected, the former energy storage return terminal Cr is connected to the cathode of the other discharge diode Dp, and the latter energy storage return terminal Cr is connected to the anode of the discharge diode Dp. A further technical solution of the present invention is to further include a plurality of bus diodes Dq, and the positive terminal of the last tank circuit mated with the previous power switching device is connected to the energy storage return terminal Cf, and then to the cathode of the bus diode Dq. Connected, the capacitance of the first tank circuit mated with the latter power switching device is positive After being connected to the energy storage return terminal Cf, the terminal is connected to the anode of the bus diode Dq. A further technical solution of the present invention is to further include a plurality of bus diodes Dq, and the negative end of the capacitor of the last tank circuit mated with the previous power switching device is connected to the energy storage return terminal Cr, and then to the cathode of the bus diode Dq. Connected, the negative terminal of the first tank circuit mated with the latter power switching device is connected to the energy storage return terminal Cr, and then connected to the anode of the bus diode Dq.

According to a further technical solution of the present invention, the high voltage terminal U+ of the concentrated voltage limiting circuit U is connected to the anode of the energy concentrated diode Du, and the low voltage terminal U- is connected to the high end SD of the first power switching device Q1. The anode of the energy concentrating diode Du is connected to the energy return terminal Cf of the first tank circuit P1.

According to a further technical solution of the present invention, the high voltage terminal U+ of the centralized voltage limiting circuit U is connected to the low end WD of the last power switching device Qn, and the low voltage terminal U- of the centralized voltage limiting circuit U The anode of the energy concentrating diode Du is connected, and the cathode of the energy concentrating diode Du is connected to the energy return terminal Cr of the last tank circuit Pm. A further technical solution of the present invention is that the centralized voltage limiting circuit U is a circuit converter that feeds back incoming energy to a power supply, or a circuit that supplies the load. A further technical solution of the present invention is to further include a surge absorbing element Z for absorbing the surge voltage of the power switching device, the wave energy absorbing element Z being respectively connected in parallel with each of the storage capacitors C. The clamp voltage of the surge absorbing component is higher than the voltage regulator of the voltage limiting circuit.

The technical effect of the present invention is that the present invention constructs an automatic voltage limiting device for connecting a series of high voltage circuits, including a plurality of energy storage circuits P1 to Pm for performing energy storage, and a plurality of discharge diodes Dp. The device is coupled to the tank circuit, and at least one power switching device cooperates with the plurality of tank circuits, a tank circuit mated with the one power switch device or mated with the one power switch device The plurality of energy storage circuits are connected in series and connected in parallel at both ends of the power switching device, and the voltage-regulating circuit of the automatic voltage-dividing power switching device of the invention overcomes the clamp diode of the conventional T0220, T0247 and the like in the prior art. The problem is that the withstand voltage is low, and the power switching device that limits the withstand voltage of 3300V or higher is used in series. The clamped diode reverse cutoff voltage of the present invention is reduced by several times compared with the prior art, and the reverse recovery current is also reduced, so that the clamp diode operates in a safe working area, which greatly increases the reliability of the system. The voltage sampling range of the present invention is also reduced by several times compared to the prior art. The withstand voltage rating of other parts is also reduced. DRAWINGS

1 is a circuit diagram of a prior art 1.

2 is a circuit diagram of the prior art 2.

3 is a circuit diagram of a specific embodiment of the present invention.

4 is a circuit diagram of another embodiment of the present invention.

FIG. 5 is a series high voltage circuit of a hybrid automatic voltage limiting power switching device according to the present invention.

Figure 6 is an equivalent circuit diagram of Figure 3.

detailed description

The technical solution of the present invention will be further described below in conjunction with specific embodiments.

As shown in FIG. 3, a specific embodiment of the present invention is: constructing a series high voltage circuit of a power limiting device with automatic voltage limiting, comprising a series branch of a power switching device composed of a plurality of power switching devices Q1 to Qn, centralized voltage limiting The circuit U, the concentrated voltage limiting circuit U includes a high voltage terminal U+ and a low voltage terminal U-. The power switching device includes a control terminal, a high-end SD and a low-end WD, and the series circuit of the power switching device is connected in series in a manner that a high-end SD of one power switching device is connected to a low-end WD of another power switching device.

The present invention also includes a plurality of energy storage circuits P1 to Pm for performing energy storage, a plurality of discharge diodes Dp, a plurality of bus diodes Dq, and an energy concentration diode Du, each of the power switching devices being associated with the one or more memories The circuit can be mated, and at least one power switching device is coupled to the plurality of energy storage circuits. The energy storage circuit includes a storage capacitor C, a static grading resistor R, a clamping diode D, a tank circuit mated with the one power switching device or the plurality of storages cooperating with the one power switching device After the power circuits are connected in series, they are connected in parallel at both ends of the power switching device, and the energy storage circuit includes a storage capacitor C, a static voltage equalizing resistor R, and a clamp diode D. The storage capacitor C and the static voltage equalizing resistor R are connected in parallel. In series with the clamping diode D. The positive terminal of the storage capacitor C leads to the energy storage return terminal Cf, and the negative terminal of the storage capacitor C leads to the energy storage return terminal Cr, and the parallel storage circuit of the plurality of strings connected at both ends of one power switching device, each adjacent two A discharge diode Dp is connected between the energy storage return terminals Cf, and a discharge diode Dp is connected between each adjacent two energy storage return terminals Cr; the capacitance and convergence of the last energy storage circuit matched with the previous power switching device The cathode of the diode Dq is connected, and the capacitance of the first tank circuit coupled with the latter power switching device is connected to the anode of the bus diode Dq; the two ends of the concentrated voltage limiting circuit U are respectively connected to the energy concentrated diode Du and a power switching device .

In a specific embodiment, a surge absorbing element for absorbing a surge voltage of the power switching device is further included The z, the wave energy absorbing element Z is connected in parallel with each of the storage capacitors C, respectively.

As shown in FIG. 3, a preferred embodiment of the present invention is: in a tank circuit connected in parallel with a power switching device, the tank circuit includes a storage capacitor static voltage equalizing resistor R, and a clamp diode D. After the storage capacitor C and the static grading resistor R are connected in parallel, the energy storage return terminal Cf is connected to the cathode of the clamp diode D, and the energy storage return terminal Cr is connected to the low end WD of the power switching device, the clamp diode The anode is connected to the high end SD of the power switching device.

As shown in FIG. 3, a preferred embodiment of the present invention is: in a plurality of energy storage circuits cooperating with a power switching device, the energy storage capacitor C and the static voltage equalizing resistor R of each energy storage circuit are connected in parallel to store energy. The return terminal Cf is connected to the cathode of the clamp diode D, and the energy storage return terminal Cr is connected to the anode of the clamp diode of the next tank circuit, the anode of the clamp diode D of the first tank circuit and the corresponding power switch device The high-end SD is connected, and the energy storage return terminal Cr of the last energy storage circuit is connected to the low-end WD of the corresponding power switching device, and the discharge diode Dp is inserted between the adjacent two energy storage return terminals Cf. A storage return terminal Cf is connected to the cathode of a discharge diode Dp, and the latter energy storage return terminal Cf is connected to the anode of the discharge diode Dp, and a discharge diode Dp is connected between each adjacent two energy storage return terminals Cr. The previous energy storage return terminal Cr is connected to the cathode of the discharge diode Dp, and the latter energy storage return terminal Cr is connected to the anode of the discharge diode Dp.

As shown in FIG. 3, a preferred embodiment of the present invention is: further comprising a plurality of bus diodes Dq, wherein the positive terminal of the last tank circuit mated by the last power switching device is connected to the energy storage return terminal Cf, and then connected to the current. The cathode of the diode Dq is connected, and the positive terminal of the first tank circuit matched by the latter power switching device is connected to the energy storage return terminal Cf, and then connected to the anode of the bus diode Dq.

As shown in FIG. 3, a preferred embodiment of the present invention is: the high voltage terminal U+ of the concentrated voltage limiting circuit U is connected to the cathode of the energy concentrated diode Du, and the low voltage terminal U- and the first power switching device Q1 The high-end SD is connected, and the anode of the energy concentrated diode Du is connected to the energy return terminal Cf of the first energy storage circuit P1.

As shown in FIG. 4, a preferred embodiment of the present invention is: in a tank circuit connected in parallel with a power switching device, the tank circuit includes a storage capacitor static voltage equalizing resistor R, and a clamping diode D. After the storage capacitor C and the static grading resistor R are connected in parallel, the energy storage return terminal Cr is connected to the anode of the clamp diode D, and the energy storage return terminal Cf is connected to the high-end SD of the power switching device, and the cathode of the clamp diode D The low side WD with the power switching device.

As shown in Figure 4, a preferred embodiment of the invention is: in parallel with a power switching device In the energy storage circuit, after the storage capacitor C and the static grading resistor R of each tank circuit are connected in parallel, the energy storage return terminal Cr is connected to the anode of the clamp diode D, and the first energy storage return terminal Cf corresponds to The high-end SD of the power switching device is connected, and the remaining energy storage return terminal Cf is connected to the cathode of the clamp diode D of the previous tank circuit, and the cathode of the clamp diode D of the last tank circuit is lower than the corresponding power switch device. The terminal WD is connected, and a discharge diode Dp is connected between each adjacent two energy storage return terminals Cf. The former energy storage return terminal Cf is connected to the cathode of the discharge diode Dp, and the latter energy storage return terminal Cf and the discharge diode are connected. The anode of Dp is connected, and a discharge diode Dp is connected between each adjacent two energy storage return ends Cr. The former energy storage return terminal Cr is connected to the cathode of the other discharge diode Dp, and the latter energy storage return terminal Cr Connected to the anode of the discharge diode Dp.

As shown in FIG. 4, a preferred embodiment of the present invention is: further comprising a plurality of bus diodes Dq, wherein the negative end of the capacitor of the last energy storage circuit coupled with the last power switching device is connected to the energy storage return terminal Cr, and then connected to the current The cathode of the diode Dq is connected, and the negative end of the capacitor of the first energy storage circuit matched by the latter power switching device is connected to the energy storage return terminal Cr, and then connected to the anode of the bus diode Dq.

As shown in FIG. 4, a preferred embodiment of the present invention is: the high voltage terminal U+ of the centralized voltage limiting circuit U is connected to the low end WD of the last one of the power switching devices Qn, and the concentrated voltage limiting circuit U is low. The voltage terminal U- is connected to the anode of the energy concentration diode Du, and the cathode of the energy concentration diode Du is connected to the energy return terminal Cr of the last energy storage circuit Pm.

As shown in FIG. 5, a power switching device series circuit is provided. The first power switching device Q1 is connected in parallel with a storage circuit P1, and the second power switching device Q2 is connected in parallel with two energy storage circuits P2 and P3. . A surge absorbing element Z is connected in parallel with each end of each storage capacitor. At this time, the static grading resistor R, the storage capacitor C, the surge absorbing element Z and the storage device P2, P3 of the same type of device are stored in the storage circuit PI. The parameter value will vary depending on the circuit.

As shown in Fig. 3, Fig. 4 and Fig. 5, the capacitance of the storage capacitor C is uniformly adjusted by an adjustable voltage circuit U to realize the automatic voltage limiting of the series power switching device.

When multiple power switching devices connected in series are turned on and off, different voltages are caused by the power switching devices in series, that is, the dynamic voltage is not uniform. analyse as below:

When a plurality of power switching devices connected in series need to be turned on, one of the power switching devices Qi that is turned on slowly enters a conducting state after a short time delay such as lus after the other power switching devices have been turned on. During this time delay, the load current is passed through the tank circuit Pi, which is connected in parallel with the slow-on power switch device Qi, accumulating charges in the storage capacitor C of the circuit, causing the voltage to rise. Lift For example: If the load current is 100A, the delay time is lus, and the total capacity of the storage capacitor C is lOuF., the voltage rise of the capacitor is 10V. That is, U= I*T /C =100*1/10= lOVo

When multiple series-connected power switching devices require simultaneous turn-off, one of the fast-switching power switching devices is turned off before other power switching devices turn off, after experiencing a short time delay such as lus. The switching device also enters an off state during which the load current passes through the tank circuit Px connected across the fast-switching power switching device Qx, accumulating charges in the storage capacitor C, causing the voltage to rise. For example: If the load current is 100A, the delay time is lus. The total capacity of the storage capacitor C is lOuF., then the voltage rise of the capacitor is 10V. That is, U= I*T /C =100*1/10= lOVo Due to the discreteness of the power switching device and the control circuit and the driving circuit, there may be a plurality of storage capacitors having a voltage rise. The above calculation is the two with the highest voltage rise, one corresponding to the turn-on process, one corresponding to the turn-off process, and the most unfavorable situation. The two processes are the same as the maximum rise in the same storage capacitor voltage. In the above example, the voltage rise is at most 20V.

After a plurality of series connected power switching devices are controlled to enter a stable off period, the static grading resistor R equalizes the respective storage capacitors, and limits the series of power switching devices. At this time, all the clamp diodes are guided. All discharge diodes are turned off, and the respective storage capacitors are in series, and the voltages of the respective power switching devices are within the safe working voltage.

After the plurality of series connected power switching devices are controlled to enter a stable conduction period, all of the clamping diodes are turned off, all the discharging diodes are turned on, and the respective storage capacitors C are in parallel. The energy in each of the storage capacitors flows through the discharge diode to the centralized voltage limiting circuit U until its terminal voltage is equal to the set voltage value of the centralized voltage limiting circuit U. Here, the equivalent electrical schematic of Figure 3 is shown in Figure 6, which ignores the turn-on voltage drop of the power switching device. The concentrated voltage limiting circuit U then feeds the incoming energy back to the DC bus or provides it to the load. The centralized voltage limiting circuit U can maintain the voltage across its U+, U-.

The technical effect of the present invention is: The present invention constructs an automatic voltage limiting device for connecting a series of high voltage circuits, including a plurality of energy storage circuits P1 to Pm for performing energy storage, and a plurality of discharge diodes Dp, each of the power switching devices. Cooperating with the energy storage circuit, and at least one power switching device is matched with the plurality of energy storage circuits, and the energy storage circuit includes a storage capacitor C, a static voltage equalization resistor R, and a clamp diode D. A tank circuit mated with a power switching device or the plurality of tank circuits mated with the one power switching device is connected in series and connected in parallel at both ends of the power switching device. The voltage-regulating circuit of the automatic voltage-dividing power switching device of the invention overcomes the prior art, and the power switch having a low withstand voltage of a clamp diode of a small package such as a common T0220, T0247 and the like, and a voltage limit of 3300V or higher Device series The problem of using. The withstand voltage of the clamp diode is reduced several times compared to the prior art. The clamp diode reverse turn-off voltage of the present invention is reduced by several times compared with the prior art, and the reverse recovery current is also reduced, so that the clamp diode operates in a safe working area, which greatly increases the reliability of the system. The voltage sampling range of the invention is reduced by several times compared with the prior art. The voltage equalization precision of the power switching device is improved, and the withstand voltage level of some components is reduced.

The above is a detailed description of the present invention in connection with the specific preferred embodiments, and the specific embodiments of the present invention are not limited to the description. It will be apparent to those skilled in the art that the present invention may be practiced without departing from the spirit and scope of the invention.

Claims

Claim

1. An automatic voltage limiting device for connecting a high voltage circuit, comprising a power switching device series branch composed of a plurality of power switching devices Q1 to Qn, and a concentrated voltage limiting circuit U, wherein the power switching device comprises a control terminal and a high end SD and low-end WD, the power switching device series branch is sequentially connected in series with the high-end SD of one power switching device connected to the low-end WD of another power switching device, and the concentrated voltage limiting circuit U includes a high-voltage terminal U+ and Low voltage terminal U-;

The utility model further includes a plurality of energy storage circuits P1 to Pm for performing energy storage, a plurality of discharge diodes Dp, a plurality of bus diodes Dq, and an energy concentration diode Du, wherein each of the power switching devices and the energy storage circuit Cooperating, and at least one power switching device is coupled to the plurality of energy storage circuits, and the energy storage circuit includes a storage capacitor (a static voltage equalizing resistor R, a clamping diode D, and the power switching device) a storage circuit or the plurality of energy storage circuits cooperating with the one power switching device are connected in series, and are connected in parallel at both ends of the power switching device, and the storage capacitors (the static voltage equalizing resistors R are connected in parallel with the Clamping diode D is connected in series, the positive terminal of the storage capacitor C leads to the energy storage return terminal Cf, the negative terminal of the storage capacitor C leads to the energy storage return terminal Cr, and the parallel storage circuit of the plurality of strings connected at both ends of a power switching device a discharge diode Dp is inserted between each adjacent two energy storage return terminals Cf, and a discharge diode Dp is inserted between each adjacent two energy storage return terminals Cr;

The capacitance of the last tank circuit of the plurality of series-connected tank circuits in parallel with the last power switching device is connected to the cathode of the bus diode Dq, and the first energy storage of the plurality of series-connected tank circuits in parallel with the latter power switch device The capacitance of the circuit is connected to the anode of the bus diode Dq;

The two ends of the concentrated voltage limiting circuit U are respectively connected to the energy concentrated diode Du and a power switching device.

2 . The high voltage circuit of the automatic voltage limiting power switching device according to claim 1 , wherein in the energy storage circuit connected in parallel with a power switching device, the energy storage capacitor C and the static voltage equalizing resistor are provided. After R is connected in parallel, the energy storage return terminal Cf is connected to the cathode of the clamp diode D, and the energy storage return terminal Cr is connected to the low end WD of the power switching device, and the anode of the clamp diode and the high end of the power switching device SD is connected.

3 . The high voltage circuit of a power limiting device for automatic voltage limiting according to claim 1 , wherein in a tank circuit connected in parallel with a power switching device, the energy storage capacitor C and the static energy are static. After the state grading resistor R is connected in parallel, the energy storage return terminal Cr is connected to the anode of the clamp diode D, and the energy storage return terminal Cf is connected to the high end SD of the power switching device, the cathode of the clamp diode and the power switching device Low-end WD.

4. The high voltage circuit of an automatic voltage limiting power switching device according to claim 1, wherein a storage capacitor C of each of the energy storage circuits is in a plurality of energy storage circuits coupled to a power switching device. After the static voltage equalizing resistor R is connected in parallel, the energy storage return terminal Cf is connected to the cathode of the clamp diode D, and the energy storage return terminal Cr is connected to the anode of the clamp diode D of the next tank circuit, the first tank circuit is The anode of the clamp diode D is connected to the high-end SD of the corresponding power switching device, and the energy storage return terminal Cr of the last energy storage circuit is connected to the low-end WD of the corresponding power switching device, the previous energy storage return terminal Cf and one The cathode of the discharge diode Dp is connected, and the latter energy storage return terminal Cf is connected to the anode of the discharge diode Dp; the former energy storage return terminal Cr is connected to the cathode of the other discharge diode Dp, and the latter energy storage return terminal Cr The anode of the discharge diode Dp is connected.

5 . The high voltage limiting circuit of a power limiting device for automatic voltage limiting according to claim 1 , wherein a storage capacitor C of each of the energy storage circuits is in a plurality of energy storage circuits connected in parallel with one power switching device. 5 . After the static grading resistor R is connected in parallel, the energy storage return terminal Cr is connected to the anode of the clamp diode D, and the first energy storage return terminal Cf is connected to the high-end SD of the corresponding power switching device, and the remaining energy storage return terminals Cf and The cathode of the clamp diode D of the previous tank circuit is connected, and the cathode of the clamp diode D of the last tank circuit is connected to the lower end WD of the corresponding power switch device, the former energy storage return terminal Cf and the discharge diode Dp The cathode is connected, the latter energy storage return terminal Cf is connected to the anode of the discharge diode Dp, and the previous energy storage return terminal Cr is connected to the cathode of the other discharge diode Dp, and the latter energy storage return terminal Cr and the discharge diode Dp The anode is connected.

6 . The high voltage circuit of the automatic voltage limiting power switching device according to claim 1 , further comprising a plurality of bus diodes Dq, the positive terminal of the last energy storage circuit matched with the previous power switching device. 6 . After being connected to the energy storage return terminal Cf, it is connected to the cathode of the bus diode Dq, and the positive terminal of the first energy storage circuit matched with the latter power switching device is connected to the energy storage return terminal Cf, and then connected to the bus diode Dq. The anodes are connected.

7. The high voltage circuit of an automatic voltage limiting power switching device according to claim 1, further comprising a plurality of bus diodes Dq, the last one of which cooperates with the previous power switching device. After the negative end of the capacitor of the energy circuit is connected to the energy storage return terminal Cr, it is connected to the cathode of the bus diode Dq, and the negative end of the capacitor of the first energy storage circuit matched with the latter power switching device is connected to the energy storage return terminal Cr. And connected to the anode of the bus diode Dq.

8 . The high voltage circuit of the power limiting device of the automatic voltage limiting device according to claim 1 , wherein the high voltage terminal U+ of the concentrated voltage limiting circuit U is connected to the cathode of the energy concentrated diode Du, and the low voltage terminal U is connected. - connected to the high-end SD of the first power switching device Q1, the anode of which is connected to the energy return terminal Cf of the first tank circuit P1.

9 . The high voltage circuit of the power limiting device of the automatic voltage limiting device according to claim 1 , wherein the high voltage terminal U+ of the centralized voltage limiting circuit U and the low end WD of the last power switching device Qn are Connected, the low voltage terminal U- of the concentrated voltage limiting circuit U is connected to the anode of the energy concentrated diode Du, and the cathode of the energy concentrated diode Du is connected to the energy return terminal Cr of the last energy storage circuit Pm.

10 . The high voltage circuit of the automatic voltage limiting power switching device according to claim 1 , wherein the centralized voltage limiting circuit U is a circuit converter that feeds back the energy into the power supply, or provides the load to the load. Circuit.

11. The high voltage circuit of an automatic voltage limiting power switching device according to claim 1, further comprising a surge absorbing element z for absorbing a surge voltage of said power switching device, said surge absorption The elements τ are respectively connected in parallel with each of the storage capacitors c.