Hybrid Bidirectional Electromagnetic Interference Filter, Control Method and Medium

Abstract

The present invention relates to the technical field of electromagnetic compatibility of power electronic devices, and particularly to a hybrid bidirectional electromagnetic interference filter, a control method and a medium. It includes a first suppression unit and a second suppression unit. The first end of the first suppression unit is connected to the grid side, and the second end of the first suppression unit is grounded; the first end of the second suppression unit is connected to the primary side of the power converter, and the second end of the first suppression unit is grounded; a common-mode inductor is also provided between the grid side and the power converter. The system of the present invention can solve the suppression of conducted interference of power electronic devices, improve the immunity of the power converter, and at the same time improve the power density of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic compatibility of power electronic devices, and particularly to a hybrid bidirectional electromagnetic interference filter, a control method and a medium. Background Art

[0002] With the development of new energy technologies, the penetration rate of power electronic devices in the power grid has increased significantly. Power electronics technology is one of the key technologies in future smart grids. While performing power conversion, power electronic devices operating in the switching state generate high du / dt and di / dt (voltage and current change rates), and produce conducted and radiated interference, threatening the normal operation of surrounding devices. With the development of power electronic devices towards high frequency and high power density, especially the application of wide bandgap power switching devices, more serious electromagnetic interference problems will arise. The traditional passive EMI filter for suppressing conducted interference is relatively large in volume and weight, accounting for 30% - 50% of the entire power converter, which is one of the main factors affecting the integrated development of power converters. Using an active EMI filter can significantly reduce the volume and weight of the EMI filter, which is one of the key technologies for the development of high power density power converters. Traditional passive EMI filters usually have bidirectional EMI suppression capabilities, which can reduce the electromagnetic emissions of power electronic devices and improve their anti-interference level at the same time. Currently, the research on active EMI filters mainly focuses on suppressing the electromagnetic emissions generated by power electronic devices themselves, and less consideration is given to the bidirectional interference suppression problem. The active bidirectional EMI suppression scheme using only the double CSCC face-to-face structure has good suppression capabilities for interference sources with relatively low interference intensities. However, when the interference intensity is high, it is difficult to achieve an ideal interference suppression level due to the low insertion loss of the unity gain feedback CSCC and the parameter sensitivity of the feedforward CSCC for broadband operation. Therefore, further research on the bidirectional electromagnetic interference suppression filter based on the active method is needed.

[0003] During the operation of power electronic devices, serious electromagnetic interference will be generated due to the high-frequency operation of power electronic switches, which can easily cause the surrounding electrical and electronic devices to malfunction or even be damaged. The traditional passive EMI filter for suppressing interference, due to its large volume and heavy weight, severely restricts the improvement of the power density of power converters, especially in medium and high-power applications. The active EMI filter developed in recent years uses components with higher power density, which can significantly reduce the volume and weight of the EMI filter, and is one of the important ways to improve the power density of power converters, thus attracting wide attention. Currently, the two-way EMI suppression ability of active EMI filters is rarely considered, while traditional passive EMI filters usually have two-way interference suppression. While solving the conducted emissions of the device, it can improve the immunity of the device itself, enabling the device to have good electromagnetic compatibility. Therefore, the present invention proposes a hybrid EMI filter with two-way interference suppression ability, adopting a double CSCC structure with decoupling inductors and performing unity-gain control to ensure that the system can operate stably while achieving two-way interference suppression. Summary of the Invention

[0004] During the operation of power converters, serious electromagnetic interference will be generated due to the high-frequency operation of power switches, which can easily cause the surrounding electrical and electronic devices to malfunction. The traditional method for suppressing interference is to use passive EMI filters, but their power density is very low, occupying a large amount of space and weight in power converters. Under the development trend of high frequency and high power density in power converters, it is urgent to solve the problem of high volume and weight of passive EMI filters. Active EMI filters use components with higher power density to form an active interference cancellation circuit, which can significantly improve the power density of power converters. Traditional active EMI filters mainly focus on the interference suppression problem on the power converter side, while passive EMI filters actually have two-way interference suppression ability, which can improve the immunity of power converters. Therefore, the present invention proposes an active EMI filter with two-way interference suppression ability, adopting a double CSCC face-to-face structure and performing unity-gain control to achieve two-way interference suppression. While suppressing the conducted interference of power converters, it improves their immunity.

[0005] The present invention mainly aims at the problems of low power density in passive suppression of conducted interference in power electronic devices, most active suppressions only having one-way EMI suppression ability, and the double CSCC face-to-face structure being restricted by unity-gain control and being sensitive to broadband parameters, and proposes a hybrid two-way EMI suppression filter. A small decoupling inductor or a small passive EMI filter is inserted between the CSCC feedforward and CSCC feedback active circuits of this topology. The CSCC feedforward and CSCC feedback active circuits are controlled in the unity-gain mode, enabling it to have high two-way EMI suppression ability and improving the stability of the system.

[0006] A hybrid bidirectional electromagnetic interference filter includes a first suppression unit and a second suppression unit. The first end of the first suppression unit is connected to the grid side, and the second end of the first suppression unit is grounded; the first end of the second suppression unit is connected to the primary side of the power converter, and the second end of the second suppression unit is grounded; a common mode inductor is also provided between the grid side and the power converter.

[0007] Preferably, the first suppression unit includes a first current transformer and a first CSCC. The first current transformer is coupled to the bus, the output of the first current transformer is connected to the first end of the first CSCC, and the second end of the first CSCC is grounded; the second suppression unit includes a second current transformer and a second CSCC. The first end of the second current transformer is connected to the grid side, the second end of the second current transformer is connected to the first end of the second CSCC, and the second end of the second CSCC is grounded, where CSCC is a current detection current compensation module.

[0008] Preferably, the first CSCC includes a first sampling resistor R1, a first inverting op-amp component, a first push-pull circuit, and a first injection branch. The first end and the second end of the first sampling resistor R1 are respectively connected to the output end of the first current transformer. The first injection branch includes a first injection resistor R 1in and a first injection capacitor C 1in . The first end of the first injection resistor R 1in is connected to the first end of the first inverting op-amp component through the first push-pull circuit. The second end of the first injection resistor R 1in is connected to the first end of the first injection capacitor C 1in , and the second end of the first injection capacitor C 1in is grounded.

[0009] Preferably, the second CSCC includes a second sampling resistor R2, a second inverting op-amp component, and a second injection branch. The first end and the second end of the second sampling resistor R2 are respectively connected to the output end of the second current transformer. The second injection branch includes a second injection resistor R 2in and a second injection capacitor C 2in . The first end of the second injection resistor R 2in is connected to the first end of the second inverting op-amp component through the second push-pull circuit. The second end of the second injection resistor R 2in is connected to the first end of the second injection capacitor C 2in , and the second end of the second injection capacitor C 1in is grounded.

[0010] Preferably, the first inverting op-amp component includes a first inverting op-amp and a first gain resistor R 1dand the first amplification resistor R 1f , the negative electrode of the first inverting op-amp is connected to the second end of the first gain resistor R 1d , the first end of the first gain resistor R 1d is connected to the first end of the first sampling resistor R1, the second end of the first sampling resistor R1 is connected to the positive electrode of the first inverting op-amp and grounded, the first end of the first amplification resistor R 1f is connected to the first end of the first injection resistor R 1in , the second end of the first amplification resistor R 1f is connected to the output end of the first inverting op-amp, and the output end of the first inverting op-amp is also connected to the first end of the first injection resistor R 1in ;

[0011] The first push-pull circuit includes a first push-pull resistor one, a first push-pull diode one, a first push-pull diode two, and a first push-pull resistor two connected in sequence; a first push-pull resistor three and a first push-pull resistor four connected in sequence; a first push-pull triode one and a first push-pull triode two; the base of the first push-pull triode one is connected between the first push-pull resistor one and the first push-pull diode one, the collector of the first push-pull triode one is connected to one end of the first push-pull resistor one, and the emitter of the first push-pull triode one is connected to one end of the first push-pull resistor three; the base of the first push-pull triode two is connected between the first push-pull resistor two and the first push-pull diode two, the collector of the first push-pull triode one is connected to one end of the first push-pull resistor four, and the emitter of the first push-pull triode one is connected to one end of the first push-pull resistor two; the first end of the first injection resistor R 1in is connected between the first push-pull resistor three and the first push-pull resistor four; the first push-pull diode one and the first push-pull diode two are connected in series in the forward direction.

[0012] Preferably, the second inverting op-amp component includes a second inverting op-amp, a second gain resistor R 2d , and a second amplification resistor R 2f , the negative electrode of the second inverting op-amp is connected to the second end of the second gain resistor R 2d , the second end of the second gain resistor R 2d is connected to the first end of the second sampling resistor R2, the second end of the second sampling resistor R2 is connected to the positive electrode of the second inverting op-amp and grounded, the first end of the second amplification resistor R 2f is connected to the first end of the second injection resistor R 2in , the second end of the second amplification resistor R 2f is connected to the output end of the second inverting op-amp, and the output end of the second inverting op-amp is also connected to the first end of the second injection resistor R 2in ;

[0013] The second push-pull circuit includes a first second push-pull resistor, a first second push-pull diode, a second second push-pull diode, and a second second push-pull resistor connected in sequence; a third second push-pull resistor and a fourth second push-pull resistor connected in sequence; a first second push-pull triode and a second second push-pull triode; the base of the first second push-pull triode is connected between the first second push-pull resistor and the first second push-pull diode, the collector of the first second push-pull triode is connected to one end of the first second push-pull resistor, and the emitter of the first second push-pull triode is connected to one end of the third second push-pull resistor; the base of the second second push-pull triode is connected between the second second push-pull resistor and the second second push-pull diode, the collector of the first second push-pull triode is connected to one end of the fourth second push-pull resistor, and the emitter of the first second push-pull triode is connected to one end of the second second push-pull resistor; the first end of the first injection resistor R 1in is connected between the third second push-pull resistor and the fourth second push-pull resistor; the first second push-pull diode and the second second push-pull diode are connected in forward sequence.

[0014] A control method for a hybrid bidirectional electromagnetic interference filter, including

[0015] Grid-side interference cancellation, specifically, the first CSCC extracts the conducted interference current, converts it into an interference voltage, and reconstructs and processes it through the first inverting op-amp component, and injects the reconstructed interference current into the ground after inputting the processed voltage into the first injection branch, where the push-pull circuit is used to improve the load-carrying capacity of the CSCC; the second CSCC extracts the remaining conducted interference current, converts it into an interference voltage, and reconstructs and processes it through the second inverting op-amp component, and injects the reconstructed interference current into the ground after inputting the processed voltage into the second injection branch, where the push-pull circuit is used to improve the load-carrying capacity of the CSCC; the decoupling inductor is enhanced by the inductance of the first CSCC, which can further improve the interference suppression ability;

[0016] Primary-side interference cancellation of the power converter, specifically, the second CSCC extracts the conducted interference current, converts it into an interference voltage, and reconstructs and processes it through the second inverting op-amp component, and injects the reconstructed interference current into the ground after inputting the processed voltage into the second injection branch, where the push-pull circuit is used to improve the load-carrying capacity of the CSCC; the first CSCC extracts the remaining conducted interference current, converts it into an interference voltage, and reconstructs and processes it through the first inverting op-amp component, and injects the reconstructed interference current into the ground after inputting the processed voltage into the first injection branch, where the push-pull circuit is used to improve the load-carrying capacity of the CSCC; the decoupling inductor is enhanced by the inductance of the second CSCC, which can further improve the interference suppression ability.

[0017] Preferably, it includes

[0018] The current transformer extracts the conducted interference current, sends it to the sampling resistor, converts the interference current into an interference voltage, and uses it as the input voltage of the subsequent-stage op-amp;

[0019] The operational amplifier processes the input interference voltage and outputs it to the injection branch;

[0020] The output reconstructed interference injects the reconstructed interference current into the ground through the injection branch to achieve in-phase cancellation with the original interference current, and the push-pull circuit is used to improve the ability of the injected current.

[0021] Preferably, the current transformer extracts the conducted interference current according to 1:n, sends it to the second sampling resistor R2, converts the interference current into an interference voltage, and uses it as the input voltage of the subsequent-stage operational amplifier, where n is a positive integer from 1 to 10.

[0022] A computer medium stores a program that can run the above method steps.

[0023] Therefore, the present invention has the following advantages: In the present invention, the current transformer extracts the conducted interference current from the bus for the reconstructed interference current of the hybrid active EMI filter; the sampling resistor converts the extracted conducted interference current into an interference voltage for the operational amplifier to adjust the voltage; the operational amplifier with a push-pull inverts the interference voltage and provides sufficient interference current for interference current injection and cancellation; the injection branch converts the reconstructed interference voltage output by the operational amplifier into an interference current and injects it into the ground to cancel the original interference current, achieving the suppression of the interference current. The proposed hybrid bidirectional active EMI filter adopts a dual CSCC scheme with decoupling inductors, which can achieve bidirectional suppression of interference.

[0024] The system of the present invention can solve the suppression of conducted interference in power electronic devices, improve the immunity of power converters, and at the same time increase the power density of the system. Brief Description of the Drawings

[0025] Figure 1 It is the example principle of the present invention.

[0026] Figure 2 It is Figure 1 The schematic diagram of the specific circuit structure principle when CSCC works in

[0027] Figure 3 It is Figure 1 The schematic diagram of the specific circuit structure principle when CSCC works in

[0028] Figure 4 It is the topology of the specific circuit structure embodiment of the present invention.

[0029] Figure 5 In the present invention, the decoupling inductor can be replaced by passive filtering elements such as CLC in the figure.

[0030] Figure 6 It is the simulation result of the conducted interference of a 120kHz PFC power supply. Detailed Description of the Invention

[0031] The technical solution of the present invention will be specifically described below in conjunction with the accompanying drawings and embodiments.

[0032] The basic principle of the present invention is as follows:

[0033] As Figure 2 shown, before adopting the bidirectional hybrid EMI filter, the interference current obtained by the linear impedance stabilization network is

[0034] (1)

[0035] Among them, i s is the interference current of the power electronic device obtained by the linear impedance stabilization network, i nc is the interference current emitted by the power electronic device, Z lisn is the equivalent impedance of the linear impedance stabilization network, Z nc is the equivalent impedance of the interference source of the power electronic device.

[0036] After adopting the bidirectional hybrid EMI filter, the interference current obtained by the linear impedance stabilization network is

[0037] (2)

[0038] Among them, the loop gain of CSCC1 is A cg , the loop gain of CSCC2 is A cn ; Z L is the impedance of the decoupling inductor; when A cn operates close to 1 and A cg operates at a relatively large value, better interference suppression effects can be achieved. After the impedance of the decoupling inductor is enhanced, the interference suppression ability is improved, especially in the high-frequency band.

[0039] As Figure 3 shown, before adopting the hybrid EMI filter, the interference current obtained by the linear impedance stabilization network is

[0040] (3)

[0041] Among them, i s is the interference current of the power electronic device obtained by the linear impedance stabilization network, i gc is the interference current on the grid side, Z lisn is the equivalent impedance of the linear impedance stabilization network, Z ng is the equivalent impedance of the interference source on the grid side.

[0042] After adopting the active EMI filter, the interference current obtained by the linear impedance stabilization network is

[0043] (4)

[0044] Among them, the loop gain of the first CSCC is A cg , and the loop gain of the second CSCC is A cn ; It can be seen that when A cg is close to 1 and A cn is relatively large, better interference suppression effect can be achieved. After the decoupling inductance impedance is enhanced, the interference suppression ability is improved, especially in the high-frequency band.

[0045] In summary, in the control of the hybrid bidirectional EMI filter, ensuring A cn and A cg are both close to 1 can effectively suppress interference. The introduction of a small decoupling inductance, due to adding a zero point, can effectively improve the stability of the system, and at the same time, affected by the multiplication effect, the interference suppression ability can be further improved.

[0046] As Figure 1 shown, i gc is the equivalent grid-side interference current source, i nc is the equivalent power electronic device interference current source. When the power electronic device works, serious conduction interference will be generated. According to the regulations of the electromagnetic compatibility standard, the interference needs to be suppressed below the standard-specified limit value. At the same time, there will also be interference current flowing into the power electronic device from the grid side, forming bidirectional interference. At present, the active EMI filter mainly focuses on suppressing the conduction interference of the power electronic device. To further improve the immunity of the device itself and enhance its electromagnetic compatibility, the present invention proposes an improved hybrid EMI filter, adopting a dual CSCC active EMI filter structure with a decoupling inductance in the middle, and realizing bidirectional suppression of interference through unit gain control.

[0047] As Figure 2 , Figure 3 and Figure 4 shown, in the embodiment, a hybrid bidirectional electromagnetic interference filter includes a first suppression unit and a second suppression unit. The first end of the first suppression unit is connected to the grid side, and the second end of the first suppression unit is grounded; the first end of the second suppression unit is connected to the primary side of the power converter, and the second end of the second suppression unit is grounded; a common-mode inductor is also provided between the grid side and the power converter.

[0048] The first suppression unit includes a first current transformer and a first CSCC. The first current transformer is coupled to the bus. The output of the first current transformer is connected to the first end of the first CSCC, and the second end of the first CSCC is grounded. The second suppression unit includes a second current transformer and a second CSCC. The first end of the second current transformer is connected to the grid side, the second end of the second current transformer is connected to the first end of the second CSCC, and the second end of the second CSCC is grounded. Here, CSCC is a current detection current compensation module.

[0049] The first CSCC includes a first sampling resistor R1, a first inverting op-amp component, a first push-pull circuit, and a first injection branch. The first end and the second end of the first sampling resistor R1 are respectively connected to the output end of the first current transformer. The first injection branch includes a first injection resistor R 1in and a first injection capacitor C 1in . The first end of the first injection resistor R 1in is connected to the first end of the first inverting op-amp component through the first push-pull circuit. The second end of the first injection resistor R 1in is connected to the first end of the first injection capacitor C 1in . The second end of the first injection capacitor C 1in is grounded.

[0050] The second CSCC includes a second sampling resistor R2, a second inverting op-amp component, and a second injection branch. The first end and the second end of the second sampling resistor R2 are respectively connected to the output end of the second current transformer. The second injection branch includes a second injection resistor R 2in and a second injection capacitor C 2in . The first end of the second injection resistor R 2in is connected to the first end of the second inverting op-amp component through the second push-pull circuit. The second end of the second injection resistor R 2in is connected to the first end of the second injection capacitor C 2in . The second end of the second injection capacitor C 1in is grounded.

[0051] The first inverting op-amp component includes a first inverting op-amp, a first gain resistor R 1d and a first amplification resistor R 1f . The negative pole of the first inverting op-amp is connected to the second end of the first gain resistor R 1d . The first end of the first gain resistor R 1d is connected to the first end of the first sampling resistor R1. The second end of the first sampling resistor R1 is connected to the positive pole of the first inverting op-amp and grounded. The first end of the first amplification resistor R 1f is connected to the first injection resistor R 1inis connected to the first end, and the first amplification resistor R 1f The second end of is connected to the output end of the first inverting op-amp, and the output end of the first inverting op-amp is also connected to the first injection resistor R 1in The first end of;

[0052] The first push-pull circuit includes a first push-pull resistor one, a first push-pull diode one, a first push-pull diode two, and a first push-pull resistor two connected in sequence; a first push-pull resistor three and a first push-pull resistor four connected in sequence; a first push-pull triode one and a first push-pull triode two; the base of the first push-pull triode one is connected between the first push-pull resistor one and the first push-pull diode one, the collector of the first push-pull triode one is connected to one end of the first push-pull resistor one, and the emitter of the first push-pull triode one is connected to one end of the first push-pull resistor three; the base of the first push-pull triode two is connected between the first push-pull resistor two and the first push-pull diode two, the collector of the first push-pull triode one is connected to one end of the first push-pull resistor four, and the emitter of the first push-pull triode one is connected to one end of the first push-pull resistor two; the first injection resistor R 1in The first end of is connected between the first push-pull resistor three and the first push-pull resistor four; the first push-pull diode one and the first push-pull diode two are connected in series in the forward direction.

[0053] The second inverting op-amp component includes a second inverting op-amp, a second gain resistor R 2d And a second amplification resistor R 2f , the negative pole of the second inverting op-amp is connected to the second end of the second gain resistor R 2d , the second end of the second gain resistor R 2d The second end of is connected to the first end of the second sampling resistor R2, the second end of the second sampling resistor R2 is connected to the positive pole of the second inverting op-amp and grounded, and the first end of the second amplification resistor R 2f Is connected to the first end of the second injection resistor R 2in , the first end of the second amplification resistor R 2f The second end of is connected to the output end of the second inverting op-amp, and the output end of the second inverting op-amp is also connected to the first end of the second injection resistor R 2in The first end of.

[0054] The second push-pull circuit includes a first second push-pull resistor, a first second push-pull diode, a second second push-pull diode, and a second second push-pull resistor connected in sequence; a third second push-pull resistor and a fourth second push-pull resistor connected in sequence; a first second push-pull triode and a second second push-pull triode; the base of the first second push-pull triode is connected between the first second push-pull resistor and the first second push-pull diode, the collector of the first second push-pull triode is connected to one end of the first second push-pull resistor, and the emitter of the first second push-pull triode is connected to one end of the third second push-pull resistor; the base of the second second push-pull triode is connected between the second second push-pull resistor and the second second push-pull diode, the collector of the first second push-pull triode is connected to one end of the fourth second push-pull resistor, and the emitter of the first second push-pull triode is connected to one end of the second second push-pull resistor; the first end of the first injection resistor R 1in is connected between the third second push-pull resistor and the fourth second push-pull resistor; the first second push-pull diode and the second second push-pull diode are connected in forward sequence.

[0055] In this embodiment,

[0056] The current transformer extracts the conducted interference current from the bus, which is converted into an interference voltage by the sampling resistors R1 and R2 of the first CSCC and the second CSCC, and is respectively sent to the inverting op-amps with push-pull circuits of the first CSCC and the second CSCC.

[0057] The inverting op-amp with a push-pull circuit amplifies and inverts the interference voltage and then sends it to the injection branch. The amplification factors are respectively determined by R 1f / R 1d and R 2f / R 2d .

[0058] The injection branch is composed of resistors R 1in , R 2in and capacitors C 1in , C 2in , which converts the reconstructed interference voltage into an inverting injection interference current to achieve cancellation of the original interference current.

[0059] As Figure 5 shown, the decoupling inductor can be replaced by passive filter elements such as CLC, which can further improve the high-frequency suppression ability of interference. Figure 6 is the simulation result of the conducted interference of a 120 kHz PFC power supply. The original interference before using the hybrid EMI filter significantly exceeded the standards (military standards and national standards). After using the hybrid EMI filter, the conducted interference met the standards, and the decoupling inductor was only 15 uH.

[0060] The specific steps of a control method for a hybrid bidirectional electromagnetic interference filter provided in the embodiment are as follows:

[0061] In the first step, the current transformer of the first CSCC extracts the bus interference current according to 1:n and sends it to the sampling resistor R1. The sampling resistor R1 converts the interference current into an interference voltage, which serves as the input voltage of the subsequent operational amplifier. Here, n is a positive integer ranging from 1 to 10.

[0062] In the second step, the operational amplifier processes the input interference voltage and sends it to the R 1in C 1in injection branch, where the standard push-pull circuit is used to improve the load-carrying capacity.

[0063] In the third step, the reconstructed interference voltage output by the operational amplifier passes through the resistor R 1in and capacitor C 1in to inject the reconstructed interference current into the ground, achieving anti-phase cancellation with the original interference current, thereby effectively suppressing the interference.

[0064] In the fourth step, the current transformer of the second CSCC extracts the bus interference current according to 1:n and sends it to the sampling resistor R2. The sampling resistor R2 converts the interference current into an interference voltage, which serves as the input voltage of the subsequent operational amplifier.

[0065] In the fifth step, the operational amplifier processes the input interference voltage and outputs it to the R 2in C 2in injection branch, where the standard push-pull circuit is used to improve the load-carrying capacity.

[0066] In the sixth step, the reconstructed interference voltage output by the operational amplifier passes through the resistor R 2in and capacitor C 2in to inject the reconstructed interference current into the ground, achieving anti-phase cancellation with the original interference current, thereby effectively suppressing the interference.

[0067] After the above steps, the system forms a CSCC feedforward-feedback cascaded hybrid active EMI filter with a decoupling inductor in the middle, which can attenuate the bidirectional interference between the grid side and the power electronic device, effectively suppress the conducted interference of the power electronic device, and also attenuate the grid side conducted interference, enhancing the electromagnetic compatibility of the power electronic device. For the conducted interference current generated by the power electronic device, CSCC1 operates in a feedback manner. The current transformer extracts the conducted interference emitted by the power electronic device from the bus, reconstructs the inverted interference through the amplifier, and injects the inverted current into the bus on the power electronic device side through the injection branch, forming a feedback control system to achieve interference cancellation; CSCC2 operates in a feedforward manner. The current transformer extracts the conducted interference current emitted by the power electronic device, reconstructs the inverted interference through the amplifier and injects it into the bus on the grid side, forming a feedforward interference cancellation system to achieve interference suppression. For the grid side interference, CSCC1 operates in a feedforward manner. The current transformer extracts the grid side conducted interference current, reconstructs the inverted interference through the operational amplifier, and injects the reconstructed interference into the bus on the power electronic device side through the injection branch, forming a feedforward interference cancellation system to achieve interference suppression. CSCC2 operates in a feedback manner. The conducted interference current emitted by the power electronic device is extracted from the bus through the current transformer, the inverted interference is reconstructed through the operational amplifier, and the reconstructed interference current is injected back into the bus on the grid side, forming a feedback control system to achieve interference cancellation. To enable the bidirectional EMI suppression system to operate stably, CSCC1 and CSCC2 must operate in the unity gain mode. The small decoupling common mode inductor between CSCC1 and CSCC2 can solve the problem of broadband parameter sensitivity in the feedforward mode and enhance the high-frequency interference suppression ability of the system.

[0068] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains may make various modifications or supplements to the described specific embodiments or use similar methods for substitution, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A hybrid bidirectional electromagnetic interference filter, characterized in that: It includes a first suppression unit and a second suppression unit, wherein the first end of the first suppression unit is connected to the grid side, and the second end of the first suppression unit is grounded; the first end of the second suppression unit is connected to the primary side of the power converter, and the second end of the second suppression unit is grounded; a common mode inductor is also provided between the grid side and the power converter; The first suppression unit includes a first current transformer and a first CSCC, the first current transformer is coupled to a bus, the output of the first current transformer is connected to a first end of the first CSCC, and the second end of the first CSCC is grounded; the second suppression unit includes a second current transformer and a second CSCC, the first end of the second current transformer is connected to a grid side, the second end of the second current transformer is connected to a first end of the second CSCC, and the second end of the second CSCC is grounded, wherein the CSCC is a current detection current compensation module; The first CSCC and the second CSCC are connected in a mirrored manner.

2. A hybrid bidirectional electromagnetic interference filter according to claim 1, characterized in that: The first CSCC includes a first sampling resistor R1, a first inverting operational amplifier component, a first push-pull circuit and a first injection branch. The first end and the second end of the first sampling resistor R1 are respectively connected to the output end of the first current transformer. The first injection branch includes a first injection resistor R1 connected in sequence. 1in and the first injection capacitor C 1in , the first injection resistor R 1in The first end of the first push-pull circuit is connected to the first end of the first inverting operational amplifier component, and the first injection resistor R 1in The second end of the first injection capacitor C 1in The first end of the first injection capacitor C 1in The second end is grounded.

3. A hybrid bidirectional electromagnetic interference filter according to claim 1, characterized in that: The second CSCC includes a second sampling resistor R2, a second inverting operational amplifier component and a second injection branch. The first end and the second end of the second sampling resistor R2 are respectively connected to the output end of the second current transformer. The second injection branch includes a second injection resistor R2 connected in sequence. 2in and the second injection capacitor C 2in , the second injection resistor R 2in The first end of the second push-pull circuit is connected to the first end of the second inverting operational amplifier component, and the second injection resistor R 2in The second end of the second injection capacitor C 2in The first end of the second injection capacitor C 1in The second end is grounded.

4. A hybrid bidirectional electromagnetic interference filter according to claim 2, characterized in that: The first inverting operational amplifier component includes a first inverting operational amplifier, a first gain resistor R 1d And the first amplifying resistor R 1f , the negative electrode of the first inverting op amp and the first gain resistor R 1d The second end of the first gain resistor R 1d The first end of the first sampling resistor R1 is connected to the first end of the first sampling resistor R1, the second end of the first sampling resistor R1 is connected to the positive electrode of the first reverse operational amplifier and is grounded, and the first amplifier resistor R 1f The first end of the first injection resistor R 1in The first end of the first amplifying resistor R 1f The second end of the first inverting operational amplifier is connected to the output end of the first inverting operational amplifier, and the output end of the first inverting operational amplifier is also connected to the first injection resistor R 1in A first end is connected; The first push-pull circuit includes a first push-pull resistor 1, a first push-pull diode 1, a first push-pull diode 2 and a first push-pull resistor 2 connected in sequence; a first push-pull resistor 3 and a first push-pull resistor 4 connected in sequence; a first push-pull transistor 1 and a first push-pull transistor 2; the first push-pull transistor 1 base is connected between the first push-pull resistor 1 and the first push-pull diode 1, the first push-pull transistor 1 collector is connected to one end of the first push-pull resistor 1, and the first push-pull transistor 1 emitter is connected to one end of the first push-pull resistor 3; the first push-pull transistor 2 base is connected between the first push-pull resistor 2 and the first push-pull diode 2, the first push-pull transistor 1 collector is connected to one end of the first push-pull resistor 4, and the first push-pull transistor 1 emitter is connected to one end of the first push-pull resistor 2; the first injection resistor R 1in The first end is connected between the first push-pull resistor three and the first push-pull resistor four; the first push-pull diode one and the first push-pull diode two are forward connected in sequence.

5. A hybrid bidirectional electromagnetic interference filter according to claim 3, characterized in that: The second inverting operational amplifier component includes a second inverting operational amplifier, a second gain resistor R 2d And the second amplifying resistor R 2f , the negative electrode of the second inverting op amp and the second gain resistor R 2d The second end of the second gain resistor R 2d The second end of the second sampling resistor R2 is connected to the first end of the second sampling resistor R2, the second end of the second sampling resistor R2 is connected to the positive electrode of the second reverse operational amplifier and is grounded, and the second amplifier resistor R 2f The first end and the second injection resistor R 2in The first end of the second amplifying resistor R 2f The second end of the second inverting operational amplifier is connected to the output end of the second inverting operational amplifier, and the output end of the second inverting operational amplifier is also connected to the second injection resistor R 2in A first end is connected; The second push-pull circuit includes a second push-pull resistor 1, a second push-pull diode 1, a second push-pull diode 2 and a second push-pull resistor 2 connected in sequence; a second push-pull resistor 3 and a second push-pull resistor 4 connected in sequence; a second push-pull transistor 1 and a second push-pull transistor 2; the base of the second push-pull transistor 1 is connected between the second push-pull resistor 1 and the second push-pull diode 1, the collector of the second push-pull transistor 1 is connected to one end of the second push-pull resistor 1, and the emitter of the second push-pull transistor 1 is connected to one end of the second push-pull resistor 3; the base of the second push-pull transistor 2 is connected between the second push-pull resistor 2 and the second push-pull diode 2, the collector of the second push-pull transistor 1 is connected to one end of the second push-pull resistor 4, and the emitter of the second push-pull transistor 1 is connected to one end of the second push-pull resistor 2; the first injection resistor R 1in The first end is connected between the second push-pull resistor three and the second push-pull resistor four; the second push-pull diode one and the second push-pull diode two are connected in forward direction in sequence.

6. A control method for a hybrid bidirectional electromagnetic interference filter as claimed in claim 1, characterized in that: include The interference cancellation on the grid side is specifically that the first CSCC extracts the conducted interference current and converts it into an interference voltage and reconstructs it through the first reverse operational amplifier component, and inputs the processed voltage into the reconstructed interference current injection ground after the first injection branch, wherein the push-pull circuit is used to improve the load capacity of the CSCC; the second CSCC extracts the remaining conducted interference current and converts it into an interference voltage and reconstructs it through the second reverse operational amplifier component, and inputs the processed voltage into the reconstructed interference current injection ground after the second injection branch, wherein the push-pull circuit is used to improve the load capacity of the CSCC; the decoupling inductance enhances the inductance of the first CSCC, which can further improve the interference suppression capability; The interference cancellation on the primary side of the power converter is specifically that the second CSCC extracts the conducted interference current and converts it into an interference voltage, reconstructs it through the second reverse operational amplifier component, and inputs the processed voltage into the second injection branch and then injects the reconstructed interference current into the ground, wherein the push-pull circuit is used to improve the load-carrying capacity of the CSCC; the first CSCC extracts the remaining conducted interference current and converts it into an interference voltage, reconstructs it through the first reverse operational amplifier component, and inputs the processed voltage into the first injection branch and then injects the reconstructed interference current into the ground, wherein the push-pull circuit is used to improve the load-carrying capacity of the CSCC; the decoupling inductance enhances the inductance of the second CSCC, which can further improve the interference suppression capability.

7. The control method of a hybrid bidirectional electromagnetic interference filter according to claim 6, characterized in that: include The current transformer extracts the conducted interference current and sends it to the sampling resistor, which converts the interference current into interference voltage as the input voltage of the subsequent operational amplifier; The operational amplifier processes the input interference voltage and outputs it to the injection branch; The output reconstructed interference injects the reconstructed interference current into the ground through the injection branch to achieve anti-phase cancellation with the original interference current. The push-pull circuit is used to improve the injection current capability.

8. The control method of a hybrid bidirectional electromagnetic interference filter according to claim 6, characterized in that: The current transformer extracts the conducted interference current according to 1:n and sends it to the second sampling resistor R2 to convert the interference current into an interference voltage as the input voltage of the subsequent operational amplifier, where n is a positive integer of 1-10.

9. A computer medium, characterized in that A program is stored, and the program can run the control method of the hybrid bidirectional electromagnetic interference filter described in claims 6-8.

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