CN116526440A - High-voltage energy storage active power decoupling circuit of electrolytic capacitor-free driving system - Google Patents

Abstract

The invention discloses a high-voltage energy storage active power decoupling circuit of an electrolytic capacitor-free driving system, wherein the input end of a rectifying circuit unit is connected with a power grid, the positive electrode of the output end of the rectifying circuit is connected with the positive electrode of the input end of a PFC unit, and the negative electrode of the output end of the rectifying circuit is connected with the negative electrode of the input end of the PFC unit; the positive electrode of the output end of the PFC unit is connected with the positive electrode of the input end of the active power decoupling circuit, and the negative electrode of the output end of the PFC unit is connected with the negative electrode of the input end of the active power decoupling circuit; the positive electrode of the output end of the active power decoupling circuit is connected with the positive electrode of the direct current bus, and the negative electrode of the output end of the active power decoupling circuit is connected with the negative electrode of the direct current bus; the positive electrode of the input end of the motor three-phase inverter is connected with the positive electrode of the direct current bus, and the output end of the three-phase inverter is connected with the PMSM three-phase winding of the permanent magnet synchronous motor. The invention realizes the mutual independence of the power quality control of the power grid and the voltage pulsation suppression control of the direct current bus, and reduces the design difficulty of the controller.

Description

A high-voltage energy storage active power decoupling circuit for a non-electrolytic capacitor drive system

technical field

The invention relates to the design and control of the power converter topology of the electrolytic capacitor motor drive system, in particular to the active power decoupling circuit structure and bus voltage pulsation suppression, belonging to the technical field of power electronics.

Background technique

Permanent magnet synchronous motors have simple structure, high power density and high efficiency, and are widely used in industrial production, transportation and daily life. In order to achieve high-performance operation of permanent magnet motors, the DC bus of traditional motor drive systems needs to be connected in parallel with large-capacity electrolytic capacitors to absorb the pulsating power of the grid and maintain the stability of the DC bus voltage. However, the short life and poor thermal stability of electrolytic capacitors have become the main cause of frequent failures in the drive system.

The non-electrolytic capacitor drive system uses film capacitors instead of large-capacity electrolytic capacitors, which significantly improves the reliability of the drive system. However, due to cost and volume constraints, the capacity of film capacitors is only 0.1-0.2 times that of electrolytic capacitors in traditional drive systems. Practice has shown that the technical means of directly replacing large-capacity electrolytic capacitors with small-capacity film capacitors cannot effectively absorb grid pulsating power, and there is a large amplitude of double grid frequency pulsating voltage on the DC bus, which deteriorates the input power quality of the drive system and motor performance. What's more serious is that under dynamic working conditions, the input power of the drive system lags behind the change of the motor power, which further increases the pulsation of the bus voltage of the non-electrolytic capacitor drive system, resulting in a sharp decline in motor performance. In severe cases, the non-electrolytic capacitor drive system even cannot work normally. .

The active power decoupling circuit is an effective means to overcome the above problems. By controlling the energy flow between the small-capacity film power decoupling capacitor in the decoupling circuit and the film capacitor of the DC bus of the non-electrolytic capacitor drive system, the grid pulsating power is realized. Orderly control, and then achieve the purpose of suppressing the bus voltage ripple of the electrolytic capacitor drive system, is one of the current research hotspots in the field of motor drive systems. However, the power coupling between the power decoupling capacitor and the DC bus film capacitor in the existing active power decoupling circuit is tight, the control is difficult, and the bus voltage ripple suppression effect is limited. In addition, the active power decoupling circuit uses many power devices and passive devices, and it is difficult to further reduce the cost and volume of the non-electrolytic capacitor drive system, which limits the promotion and application of the non-electrolytic capacitor drive system.

Contents of the invention

Aiming at the problems of low power density and tight power coupling of the existing active power decoupling circuit, the invention proposes an active power decoupling circuit with high-voltage energy storage capacitor and complete decoupling of pulsating power. The decoupling circuit constructs two independent energy flow paths, realizes the complete decoupling of the pulsating power between the power decoupling capacitor and the DC bus capacitor, effectively suppresses the fluctuation of the DC bus voltage, and greatly improves the dynamic performance of the motor. At the same time, compared with similar circuits, the present invention can effectively reduce the current harmonics of the power grid, and achieve a significant improvement in the comprehensive performance of the motor drive system. In addition, the high voltage gain characteristic of the active power decoupling circuit of the present invention greatly increases the working voltage of the pulsating power decoupling capacitor, effectively improves the energy storage density per unit capacitor, and significantly reduces the capacitance and volume of the non-electrolytic capacitor.

In order to achieve the above object, the present invention adopts the following technical solutions:

A new type of high-voltage energy storage active power decoupling circuit, which together with a diode single-phase uncontrolled rectifier circuit, a PFC converter, a motor three-phase inverter and a permanent magnet synchronous motor (PMSM) constitute a permanent magnet synchronous motor without electrolysis Capacitive drive system. Among them, the input end of the rectification circuit unit is connected to the power grid, the positive pole of the output end of the rectification circuit is connected to the positive pole of the input end of the PFC unit, the negative pole of the output end of the rectification circuit is connected to the negative pole of the input end of the PFC unit; the positive pole of the output end of the PFC unit is connected to the positive pole of the active power decoupling circuit The positive pole of the input terminal is connected, the negative pole of the output terminal of the PFC unit is connected with the negative pole of the input terminal of the active power decoupling circuit; the positive pole of the output terminal of the active power decoupling circuit is connected with the positive pole of the DC bus, and the negative pole of the output terminal of the active power decoupling circuit The negative pole of the bus bar is connected; the positive pole of the input end of the three-phase inverter of the motor is connected with the positive pole of the DC bus bar, the negative pole of the input end of the three-phase inverter is connected with the negative pole of the DC bus bar, and the output end of the three-phase inverter is connected with the permanent magnet synchronous motor ( PMSM) three-phase winding connection; define the voltage across the first capacitor (C1) as the DC bus voltage.

The rectifier circuit unit consists of diodes D1-D4 to form a single-phase rectifier circuit; the PFC unit is constructed based on a Boost circuit, which consists of a first inductor (L1), a first switch tube (S1), and a fifth diode (D5) Composition; the high-voltage energy storage active power decoupling circuit is composed of a second inductor (L2), a first capacitor (C1), a second capacitor (C2), a second switch tube (S2), a third switch tube (S3 ) form; the three-phase motor inverter is composed of power devices T1-T6;

The output anode of the rectification circuit unit is connected to one end of the first inductor (L1), and the output cathode of the rectification unit is simultaneously connected to the source of the first switch (S1), the source of the second switch (S2), and the first capacitor The negative pole of (C1) is connected to the negative pole of the input of the three-phase inverter bridge; the drain of the first switching tube (S1) is connected to the other end of the first inductor (L1) and the anode of the fifth diode (D5); The anode of a capacitor (C1) is connected to the cathode of the fifth diode (D5), one end of the second inductance (L2), the cathode of the second capacitor (C2), and the input anode of the three-phase inverter bridge; the second switch The drain of the tube (S2) is connected to the other end of the second inductor (L2) and the source of the third switching tube (S3); the drain of the third switching tube (S3) is connected to the positive pole of the second capacitor (C2); The negative pole of the second capacitor (C2) is simultaneously connected with the cathode of the fifth diode (D5), the positive pole of the first capacitor (C1), one end of the second inductor (L2) and the positive end of the three-phase motor inverter.

The active power decoupling circuit of the present invention constructs two completely independent energy flow paths, realizes independent control of grid pulsating power, DC bus power and decoupling capacitor power, effectively avoids the DC bus voltage being affected by grid pulsating power, and realizes no Effective suppression of bus voltage ripple under the condition of electrolytic capacitors. Further, the high voltage gain characteristic of the active power decoupling circuit can greatly increase the working voltage of the power decoupling capacitor, effectively improve the energy storage density per unit capacitor, and significantly reduce the capacitance and volume of the power decoupling capacitor.

In the PFC converter of the non-electrolytic capacitor drive system, the first switching tube (S1) controls the input current of the drive system to follow the phase change of the grid voltage, and the drive system realizes the control target of high power factor and low current harmonics.

In the active power decoupling circuit of the non-electrolytic capacitor drive system, the second switch (S2) and the third switch (S3) are turned on or off according to the error between the actual value of the DC bus voltage and the given value, and the second The inductor (L2) is an energy transfer device, which realizes the transfer and control of pulsating energy between the first capacitor (C1) and the second capacitor (C2). The second inductor (L2) is designed to work in the current discontinuous mode to realize the complete decoupling of the pulsating energy between the first capacitor (C1) and the second capacitor (C2), which not only simplifies the design of the controller, but also effectively reduces the DC bus voltage pulsation.

In the active power decoupling circuit of the non-electrolytic capacitor drive system, when the second switching tube (S2) works in the chopping state and the third switching tube (S3) works in the off state, the decoupling circuit can be regarded as the first The capacitor (C1) is the input power supply, and the second capacitor (C2) is the boost circuit of the load. Therefore, the voltage of the second capacitor (C2) is much higher than the peak voltage of the power grid, and the energy storage density per unit capacitor of the second capacitor (C2) is increased. In addition, during the bus voltage ripple suppression control process, the energy of the first capacitor (C1) and the second capacitor (C2) flows alternately, corresponding to the alternate change of the current direction of the second inductor (L2). Since the inductor current cannot change abruptly, the second inductor (L2) is designed to work in the current discontinuous mode to realize energy-controlled decoupling of the first capacitor (C1) and the second capacitor (C2).

PFC unit control: the first switching tube (S1) works in the chopping state, and by controlling the charging and discharging of the first inductor (L1), the grid current can track the grid voltage change to meet the low harmonic requirements of the drive system. The specific method is: when the grid output current i _g is less than the reference current i _g ^* , the first switch tube (S1) is turned on, and the current of the first inductor (L1) rises; when the grid output current i _g is greater than the reference current i _g ^* , the first switching tube (S1) is turned off, and the first inductance (L1) drops. Through the turn-on and turn-off of the first switching tube (S1), the grid current unit power factor and low current harmonic operation are realized.

DC bus voltage pulsation suppression control: The active power decoupling circuit is used to suppress the DC bus voltage pulsation suppression. The set voltage error of the DC bus is related to the set threshold, and has nothing to do with the state of the first switching tube (S1) in the PFC converter.

When the DC bus voltage u _DC at both ends of the first capacitor (C1) is greater than the set voltage, the second switching tube (S2) works in the chopping state, and the third switching tube (S3) is in the off state: the second switching tube ( When S2) is turned on, the energy of the first capacitor (C1) is stored in the second inductor (L2) through the second switch tube (S2). When the second switch tube (S2) is turned off, the second inductor (L2) releases energy to the second capacitor (C2) through the anti-parallel diode of the third switch tube (S3), corresponding to the voltage rise of the second capacitor (C2) , the current of the second inductor (L2) decreases. In this stage, the voltage of the first capacitor (C1) is lower than the set value.

When the DC bus voltage u _DC across the first capacitor (C1) is less than the set voltage, the second switch (S2) works in the off state, and the third switch (S3) works in the chopping state: when the third switch When the tube (S3) is turned on, the energy of the second capacitor (C2) is stored in the second inductor (L2) through the third switch tube (S3). When the third switch tube (S3) is turned off, the second inductor (L2) releases energy to the first capacitor (C1) through the anti-parallel diode of the second switch tube (S2), corresponding to the voltage rise of the first capacitor (C1) , the current of the second inductor (L2) decreases. In this stage, the voltage of the first capacitor (C1) is lower than the set value.

The technical effect that the present invention has after adopting above-mentioned technical scheme is:

(1) The active power decoupling circuit proposed by the present invention has two independent energy flow paths, which realizes completely independent absorption and release of pulsating power between the power grid, power decoupling capacitor and DC bus capacitor, and effectively suppresses DC bus voltage pulsation, Realize high-performance operation of the motor drive system under various working conditions.

(2) The structure of the active power decoupling circuit proposed by the present invention is simple and reliable, realizes the independent control of the power quality control of the power grid and the suppression control of the DC bus voltage fluctuation, and reduces the difficulty of controller design. Under the premise of ensuring the system control effect, it has a higher degree of control freedom.

(3) The unique performance of the structure and principle of the present invention improves the working voltage of the pulsating power decoupling capacitor, effectively increases the energy storage density per unit capacitor, and reduces the capacitance and volume of the capacitor.

Description of drawings

Fig. 1 is the schematic diagram of the non-electrolytic capacitor driving system based on the novel power decoupling circuit proposed by the present invention;

Fig. 2 is a working principle diagram when the first switching tube (S1) of the rectifier circuit + PFC circuit in Fig. 1 is turned off;

Fig. 3 is a working principle diagram when the first switching tube (S1) of the rectifier circuit+PFC circuit in Fig. 1 is turned on;

Fig. 4 is a working principle diagram when the second switching tube (S2) of the active power decoupling circuit in Fig. 1 is turned on and the third switching tube (S3) is turned off;

Fig. 5 is a working principle diagram when the second switching tube (S2) and the third switching tube (S3) of the active power decoupling circuit in Fig. 1 are turned off;

Fig. 6 is a working principle diagram when the second switching tube (S2) of the active power decoupling circuit in Fig. 1 is turned off and the third switching tube (S3) is turned on;

Fig. 7 is a working principle diagram when the second switching tube (S2) and the third switching tube (S3) of the active power decoupling circuit in Fig. 1 are turned off;

Fig. 8 is a control strategy block diagram of the active power decoupling circuit proposed by the present invention:

(a) Grid current, power factor correction control strategy;

(b) DC bus voltage ripple suppression control strategy;

Table 1 is the control logic of the power device of the active power decoupling circuit proposed by the present invention.

Detailed ways

Below in conjunction with example, accompanying drawing and attached table, the concrete technical scheme of the present invention is described in further detail:

The invention proposes a high voltage energy storage active power decoupling circuit. The circuit consists of two power devices, two small-capacity film capacitors and an inductor. The feature is that the power between the decoupling capacitor and the DC bus capacitor is completely decoupled. On the basis of the power quality of the non-electrolytic capacitor drive system meeting the relevant standards, the DC bus voltage ripple value is further reduced, and the non-electrolytic capacitor drive is realized under dynamic conditions. The system operates with high performance; the high voltage gain characteristic of the circuit further reduces the capacity of the decoupling capacitor by increasing the working voltage of the decoupling capacitor, reduces the cost and volume of the non-electrolytic capacitor drive system, and is conducive to the promotion of the non-electrolytic capacitor drive system based on the present invention and apply.

The electrolytic capacitor drive system power converter for permanent magnet synchronous motors according to the present invention is composed of a rectifier circuit and a PFC unit A, a new type of active power decoupling circuit B and a three-phase inverter unit C, as shown in Figure 1 Show. The input terminals of the rectification circuit and PFC unit A are connected to the power grid, and the output positive pole of the rectification circuit and PFC unit A is connected to one end of the second inductor (L2), the negative pole of the second capacitor (C2), the positive pole of the first capacitor (C1), The positive pole of the input terminal of the three-phase inverter bridge is connected; the output negative pole of the rectifier circuit and the PFC unit A is simultaneously connected with the source pole of the second switch (S2), the negative pole of the first capacitor (C1) and the negative pole of the input terminal of the three-phase inverter bridge. ; The drain of the second switching tube (S2) is connected to one end of the second inductor (L2) and the source of the third switching tube (S3); the drain of the third switching tube (S3) is connected to the second capacitor (C2 ) positive pole connection; the positive pole of the first capacitor (C1) and the cathode of the fifth diode (D5), the other end of the second inductor (L2), the negative pole of the second capacitor (C2), the three-phase inverter bridge The positive pole of the input terminal is connected; the output terminal of the three-phase inverter C is connected with the three-phase winding of the permanent magnet synchronous motor.

The main control objectives of the high-voltage energy storage and complete pulsating power decoupling active power decoupling circuit in the present invention are: to control the grid current to track the phase change of the grid voltage, and to control the input power quality of the drive system to meet IEC61000-3-2 harmonics and power factor requirements; suppress the DC bus voltage pulsation, and realize the high-performance operation of the motor under steady-state and dynamic conditions. The concrete realization process of the present invention is:

The first step to realize the control goal is to adopt the double-closed-loop control strategy of DC bus voltage outer loop and grid current inner loop. The specific implementation process: the average voltage of the DC bus is obtained after sampling and the average filtering algorithm, and the error between it and the given value is obtained by the PI controller to obtain the average value of the grid current, and further multiplied by the phase of the grid to obtain the reference working current of the grid. The grid reference current and the feedback current error of the first inductor (L1) generate a modulation signal through a PI controller, and compare it with a high-frequency triangular carrier to generate a control signal for the first switching tube (S1). When the first switch tube (S1) is turned on, the current of the first inductor (L1) increases, and when the first switch tube (S1) is turned off, the current of the first inductor (L1) decreases. The grid current tracking reference value is controlled by the first switching tube (S1), and the input power quality and DC bus average voltage control of the non-electrolytic capacitor drive system are realized, as shown in Table 1, Figure 2, Figure 3 and Figure 8(a).

Table 1

The second realization step of the control goal is: according to the error between the set value and the actual value of the DC bus voltage, control the actions of the second switching tube (S2) and the third switching tube (S3), so as to realize the decoupling of pulsating power and suppress the pulsation of the DC bus voltage. Because the active power decoupling circuit is completely decoupled from the power of the first capacitor (C1), the opening or closing of the first switching tube (S1) does not affect the working state of the subsequent stage circuit. The present invention analyzes the work of the active power decoupling circuit In principle, the working state of the first switching tube (S1) is ignored, and the working status and control process of the second switching tube (S2) and the third switching tube (S3) of the active power decoupling circuit are shown in Figures 4-8. According to the on and off states of the second switch tube (S2) and the third switch tube (S3), the active power decoupling circuit has four working modes, as shown in Table 1.

State 1: the voltage of the first capacitor ( C1 ) is greater than the set DC bus voltage. The second switching tube (S2) works in a chopping state, and the third switching tube (S3) is always turned off. When the second switch tube (S2) is turned on, the first capacitor (C1) provides energy to the second inductor (L2) and the permanent magnet synchronous motor at the same time, the current of the second inductor (L2) increases, and the voltage of the first capacitor (C1) drops , see Figure 4.

When the second switch tube (S2) is turned off, the second inductor (L2) discharges to the second capacitor (C2) through the anti-parallel diode of the third switch tube (S3), the voltage of the second capacitor (C2) increases, and the first capacitor ( C1) stops supplying energy to the second inductor (L2), continues to supply energy to the motor, and the voltage of the first capacitor (C1) continues to drop, see FIG. 5 . This state ends until the voltage of the first capacitor ( C1 ) is lower than the set DC bus voltage.

State two: the voltage of the first capacitor (C1) is lower than the set DC bus voltage. In this state, the second switch tube (S2) is always turned off, and the third switch tube (S3) works in a chopping state. When the third switch tube (S3) is turned on, the second capacitor (C2) supplies energy to the second inductor (L2) through the third switch tube (S3), and the voltage of the second capacitor (C2) drops. At this time, the first capacitor (C1) provides energy to the permanent magnet synchronous motor through the three-phase inverter, and the voltage of the first capacitor (C1) drops, see FIG. 6 .

When the third switch tube (S3) is turned off, the second capacitor (C2) stops outputting energy, and the voltage of the second capacitor (C2) remains unchanged. At the same time, the second inductor (L2) supplies power to the first capacitor (C1) through the second switching tube (S2) anti-parallel diode, the current of the second inductor (L2) decreases, and the voltage of the first capacitor (C1) increases. At this time, the first capacitor (C1) and the second inductor (L2) are connected in parallel to provide energy to the permanent magnet synchronous motor through the three-phase inverter, see FIG. 7 . State two until the voltage of the first capacitor ( C1 ) is higher than the set DC bus voltage.

When the state 1 and state 2 are working, the current direction of the second inductor (L2) is opposite. During the process of suppressing bus voltage pulsation control by the above-mentioned circuit, the above-mentioned working state switches frequently. Because the direction of the inductor current cannot change suddenly, in order not to affect the switching between the two working states and improve the dynamic response capability of the active power decoupling circuit, the second inductor (L2) is designed to work in the current intermittent state, so as to realize the work of state 1 and state 2 Complete decoupling ensures the voltage ripple suppression effect of the first capacitor (C1).

In the above process, when the first capacitor (C1) transmits energy to the second capacitor (C2), the active power decoupling circuit can be regarded as a boost circuit. Therefore, the voltage of the second capacitor (C2) is higher than the voltage of the first capacitor (C1), and because the voltage of the first capacitor (C1) is higher than the peak voltage of the grid, the high voltage operation of the second capacitor (C2) is realized, which greatly improves the second capacitor (C2) Energy storage capacity.

In summary, the new active power decoupling circuit uses high-reliability small-capacity film capacitors instead of traditional large-capacity electrolytic capacitors to achieve system power decoupling, which significantly improves the reliability and working life of the motor drive system. The power decoupling circuit greatly increases the working voltage of the pulsating power decoupling capacitor, effectively improves the energy storage density per unit capacitor, and greatly reduces the capacitance and volume of the non-electrolytic capacitor. At the same time, the proposed active power decoupling circuit constructs two independent energy flow paths, realizes the decoupling power decoupling of the decoupling capacitor and the DC bus capacitor ripple, effectively suppresses the DC bus voltage ripple, and realizes the high performance of the motor drive system under steady-state and dynamic conditions. performance run. In addition, the power decoupling of the active power decoupling circuit and the power quality control strategy of the drive system grid are independent of each other, which effectively reduces the difficulty of controller design.

Claims (9)

1. A high-voltage energy storage active power decoupling circuit for an electrolytic capacitor drive system, characterized in that: it includes a rectification circuit and a PFC unit, an active power decoupling circuit, and a motor three-phase inverter connected in sequence; the rectification circuit The input terminal of the unit is connected to the power grid, the positive pole of the output terminal of the rectifier circuit is connected to the positive pole of the input terminal of the PFC unit, the negative pole of the output terminal of the rectifier circuit is connected to the negative pole of the input terminal of the PFC unit; the positive pole of the output terminal of the PFC unit is connected to the positive pole of the input terminal of the active power decoupling circuit , the negative pole of the output terminal of the PFC terminal is connected to the negative pole of the input terminal of the active power decoupling circuit; The positive pole of the input terminal of the three-phase inverter of the motor is connected with the positive pole of the DC bus, the negative pole of the input terminal of the three-phase inverter is connected with the negative pole of the DC bus, and the output terminal of the three-phase inverter is connected with the PMSM three-phase winding of the permanent magnet synchronous motor connection; define the voltage at both ends of the first capacitor (C1) as the DC bus voltage. 2. A high-voltage energy storage active power decoupling circuit for an electrolytic capacitor drive system according to claim 1, characterized in that: said rectifier circuit unit consists of diodes D1-D4 to form a single-phase rectifier circuit; said PFC The unit is composed of the first inductor (L1), the first switch tube (S1), and the fifth diode (D5). The first switch tube (S1) is connected between the first inductor (L1) and the fifth diode (D5 ); the active power decoupling circuit is composed of a second inductor (L2), a first capacitor (C1), a second capacitor (C2), a second switch tube (S2), and a third switch tube (S3); the The three-phase motor inverter is composed of power devices T1-T6; The output anode of the rectification circuit unit is connected to one end of the first inductor (L1), and the output cathode of the rectification unit is simultaneously connected to the source of the first switch (S1), the source of the second switch (S2), and the first capacitor The negative pole of (C1) is connected to the negative pole of the input of the three-phase inverter bridge; the drain of the first switching tube (S1) is connected to the other end of the first inductor (L1) and the anode of the fifth diode (D5); The anode of a capacitor (C1) is connected to the cathode of the fifth diode (D5), one end of the second inductance (L2), the cathode of the second capacitor (C2), and the input anode of the three-phase inverter bridge; the second switch The drain of the tube (S2) is connected to the other end of the second inductor (L2) and the source of the third switching tube (S3); the drain of the third switching tube (S3) is connected to the positive pole of the second capacitor (C2); The negative pole of the second capacitor (C2) is simultaneously connected with the cathode of the fifth diode (D5), the positive pole of the first capacitor (C1), one end of the second inductor (L2) and the positive end of the three-phase motor inverter. 3. A high-voltage energy storage active power decoupling circuit for an electrolytic capacitor drive system according to claim 1, characterized in that: in the rectifier circuit and the PFC unit, the first switching tube (S1) controls the input current of the drive system Following the phase change of the grid voltage, the purpose of high power factor and low current harmonic control of the drive system is realized. At the same time, the first switching tube (S1) controls the voltage of the DC bus through the duty ratio. 4. A kind of high-voltage energy storage active power decoupling circuit for non-electrolytic capacitor drive system according to claim 1, characterized in that: the first switching tube (S1) works in chopping state, by controlling the first inductor ( The charging and discharging of L1) realizes the grid current tracking grid voltage phase change, and the drive system meets the harmonic requirements of relevant standards: when the grid output current i _g is less than the reference current i _g *, the first switch tube (S1) is turned on, and the first The current of the inductor (L1) rises; when the grid output current i _g is greater than the reference current i _g *, the first switching tube (S1) is turned off, and the first inductor (L1) drops. 5. A high-voltage energy storage active power decoupling circuit for an electrolytic capacitor drive system according to claim 1, characterized in that: according to the error between the actual voltage and the set voltage of the first capacitor (C1), the control The second switching tube (S2) and the third switching tube (S3) are working, and the second inductance (L2) is used to realize the energy transfer between the first capacitor (C1) and the second capacitor (C2), thereby controlling the bus voltage pulsation . 6. A high-voltage energy storage active power decoupling circuit for an electrolytic capacitor drive system according to claim 5, characterized in that: when the DC bus voltage is higher than the set value, the second switching tube (S2) works In the chopping state, the third switch tube (S3) is turned off; when the second switch tube (S2) is turned on, the energy of the first capacitor (C1) is stored in the second inductor (L2), and the first capacitor (C1) When the voltage drops, the current of the second inductor (L2) increases; when the second switch tube (S2) is turned off, the energy stored in the second inductor (L2) is stored in the second capacitor through the anti-parallel diode of the third switch tube (S3). In (C2), the voltage of the second capacitor (C2) increases, and the current of the second inductor (L2) decreases. 7. A high-voltage energy storage active power decoupling circuit for a non-electrolytic capacitor drive system according to claim 1, characterized in that: when the DC bus voltage is lower than the set value, the second switching tube (S2) works In the off state, the third switch tube (S3) works in the chopping state; when the third switch tube (S3) is turned on, the energy of the second capacitor (C2) is stored in the second inductor (L2), and the second capacitor (C2) The voltage drops, and the current of the second inductor (L2) increases; when the third switching tube (S3) is turned off, the energy stored in the second inductor (L2) is stored in the second switching tube (S2) anti-parallel diode In the first capacitor (C1), the voltage of the first capacitor (C1) increases, and the current of the second inductor (L2) decreases. 8. A high-voltage energy storage active power decoupling circuit for a non-electrolytic capacitor drive system according to claim 1, characterized in that: the opening or closing of the first switching tube (S1) will not affect the second switching tube (S2), the working state of the third switching tube (S3), to realize the decoupling of the power quality of the power grid and the DC bus voltage control. 9. A high-voltage energy storage active power decoupling circuit for an electrolytic capacitor drive system according to claim 1, characterized in that: when the second switching tube (S2) works in the chopping state, the third switching tube (S2) S3) When working in the off state, the active power decoupling circuit can be regarded as a boost circuit with the first capacitor (C1) as the input power supply and the second capacitor (C2) as the load, and the voltage of the second capacitor (C2) is much higher Based on the voltage of the first capacitor (C1); the high voltage of the circuit is: design the second inductor (L2) to work in the current discontinuous mode, use its characteristics to further increase the working voltage of the second capacitor (C2), and effectively reduce the second capacitor (C2) ) capacitor capacity to improve the power density of the active power decoupling circuit.