CN112821877A

CN112821877A - Multiplexing EMI filter

Info

Publication number: CN112821877A
Application number: CN202011630801.8A
Authority: CN
Inventors: 那拓扑; 曲建真; 李为汉; 唐佳棋; 张千帆
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-05-18
Anticipated expiration: 2040-12-30
Also published as: CN112821877B

Abstract

Multiplexing EMI wave filter relates to the field of making an uproar. The invention aims to solve the problem that the power density of the system is reduced because the existing electric automobile integrated system needs a plurality of EMI filters in different working modes. The multiplexing EMI filter comprises a switch K1-K2, three coupling inductors, 18 common-mode capacitors and 9 differential-mode capacitors, a group of coils of the three coupling inductors corresponding to the anode of a battery and three groups of coils of the three coupling inductors corresponding to the cathode of the battery are multiplexed to be used as the common-mode inductors, leakage inductors of the common-mode inductors are used as the differential-mode inductors, 9 capacitors with the cathode facing the ground are multiplexed to be used as the common-mode capacitors, and the rest 3 capacitors are multiplexed to be used as the differential-mode capacitors. The method is used for denoising the battery in a driving mode and denoising the power grid in a charging mode.

Description

Multiplexing EMI filter

Technical Field

The invention relates to a multiplexing EMI filter in an electric automobile integrated system. Relating to the field of noise elimination.

Background

Pure Electric Vehicles (EV) and plug-in hybrid electric vehicles (PHEV) will become the mainstream vehicle models for global vehicle enterprises to meet the future strict fuel consumption and emission regulations, but insufficient charging facilities are the main factors causing the user's anxiety about mileage. An on-board battery charger (OBC) can conveniently charge the on-board battery, but the volume and the weight of the on-board converter system are increased. A multiplexed inverter system that integrates an OBC with an EV/PHEV electric drive system is one way to meet weight and space constraints, and integrating a motor driver, an OBC, and a high voltage Boost inverter, etc. has become a trend. The purpose of the electric vehicle integrated system is to improve the system power density, but the national standard has requirements on electromagnetic interference (EMI) of the motor driver and the OBC, so that the electric vehicle integrated system needs a set of EMI filter to reduce noise interference when operating in different modes, as shown in fig. 1 to 3.

Therefore, the existing electric vehicle integrated system has the following problems: in order to meet the EMI standard of the electric automobile integrated system in different modes, the size and the weight of the electric automobile integrated system are increased and the power density of the system is reduced due to the use of a plurality of sets of EMI filters.

Disclosure of Invention

The invention aims to solve the problem that the power density of the system is reduced because the existing electric automobile integrated system needs a plurality of sets of EMI filters in different working modes. A multiplexed EMI filter is now provided.

A multiplexed EMI filter applied in an electric vehicle integrated system, the multiplexed EMI filter comprising switches K1-K2, three coupling inductors, 18 common mode capacitors and 9 differential mode capacitors,

the three coupled inductors comprise a coil L_1a+Coil L_1a-Coil L_2a+Coil L_2a-Coil L_3a+Coil L_3a-Coil L_1b+Coil L_1b-Coil L_2b+Coil L_2b-Coil L_3b+Coil L_3b-Loop L of_1c+Coil L_1c-Coil L_2c+Coil L_2c-Coil L_3c+And a coil L_3c-，

The 18 common-mode capacitors are respectively a common-mode capacitor C_Y1P-C_Y9PAnd a common mode capacitor C_Y1N-C_Y9NAnd 9 differential mode capacitors are respectively differential mode capacitors C_X1-C_X9，

One end of a switch K1, one end of a switch K2 and a coil L_1c+One end is all connectedTaken together as the positive input end of the multiplexing EMI filter, the other end of the switch K1 and the coil L_1a+One end of the coil L is connected together to be used as an alternating current signal input end of the multiplexing EMI filter_1a+The other end is simultaneously connected with a common-mode capacitor C_Y1POne end, coil L_2a+One terminal sum-mode differential capacitor C_X1One end, coil L_2a+The other end is simultaneously connected with a common-mode capacitor C_Y4POne end, coil L_3a+One terminal sum-mode differential capacitor C_X4One end, coil L_3a+Another terminal, common mode capacitance C_Y7POne terminal sum-mode differential capacitor C_X7One end of the first phase positive electrode is connected with the first phase positive electrode output end of the multiplexing EMI filter, and the differential mode capacitor C_X7Another terminal, common mode capacitance C_Y7NOne end and a coil L_3a-One end of the first phase is connected with the second phase of the electromagnetic interference (EMI) filter to serve as a first phase cathode output end of the multiplexing EMI filter, and the coil L_3a-The other end is simultaneously connected with a differential mode capacitor C_X4Another terminal, common mode capacitance C_Y4NOne end and a coil L_2a-One end, coil L_2a-The other end is simultaneously connected with a differential mode capacitor C_X1Another terminal, common mode capacitance C_Y1NOne end and a coil L_1a-One end, coil L_1a-Another end, coil L_1c-One end and a coil L_1b-One end of the first and second filters is connected together to be used as the cathode output end of the multiplexing EMI filter,

coil L_1b-The other end is simultaneously connected with a differential mode capacitor C_X2One terminal, common mode capacitance C_Y2NOne end and a coil L_2b-One end, coil L_2b-The other end is simultaneously connected with a differential mode capacitor C_X5One terminal, common mode capacitance C_Y5NOne end and a coil L_3b-One end, coil L_3b-Another terminal, differential mode capacitance C_X8One terminal and a common mode capacitor C_Y8NOne end of the differential mode capacitor C is connected together to be used as a second phase negative input end of the multiplexing EMI filter_X8Another terminal, common mode capacitance C_Y8POne end and a coil L_3b+One end of the first phase is connected together to be used as a second phase anode output end of the multiplexing EMI filter, and the coil L_3b+The other end is simultaneously connected with a differential mode capacitor C_X5Another terminal, common mode capacitance C_Y5POne end and a coil L_2b+One end, coil L_2b+The other end is simultaneously connected with a differential mode capacitor C_X2Another terminal, common mode capacitance C_Y2POne end of (1) and a coil L_1b+One end, coil L_1b+The other end is connected with the switch K2 to be used as the other alternating current signal input end of the multiplexing EMI filter,

coil L_1c+The other end is simultaneously connected with a differential mode capacitor C_X3One terminal, common mode capacitance C_Y3POne end and a coil L_2c-One end, coil L_2c-The other end is simultaneously connected with a differential mode capacitor C_X6One terminal, common mode capacitance C_Y6POne end and a coil L_3c-One end, coil L_3c-The other end is simultaneously connected with a differential mode capacitor C_X9One terminal and a common mode capacitor C_Y9POne end of the differential mode capacitor C is connected with the third phase positive electrode output end of the multiplexing EMI filter_X9Another terminal, common mode capacitance C_Y9NOne end and a coil L_3c-One end of the first phase is connected with the second phase as the third phase negative input end of the multiplexing EMI filter, and the coil L_3c-The other end is simultaneously connected with a differential mode capacitor C_X6Another terminal, common mode capacitance C_Y6NOne end and a coil L_2c-One end, coil L_2c-The other end is simultaneously connected with a differential mode capacitor C_X3Another terminal, common mode capacitance C_Y3NOne end and a coil L_1c-The other end of the first tube is provided with a first end,

common mode capacitor C_Y1P-C_Y9PThe other end and a common-mode capacitor C_Y1N-C_Y9NAre connected to the power ground.

Preferably, the multiplexed EMI filter further comprises a controller,

and the controller is used for controlling the switches K1-K2 to be opened or closed simultaneously.

Preferably, the multiplexed EMI filter includes three coupling inductors, 18 common mode capacitors and 9 differential mode capacitors,

Coil L_1a+One end, coil L_1b+One end and a coil L_1c+One end of the coil L is connected together to be used as the positive input end of the multiplexing EMI filter_1a+The other end is simultaneously connected with a common-mode capacitor C_Y1POne end, coil L_2a+One terminal sum-mode differential capacitor C_X1One end, coil L_2a+The other end is simultaneously connected with a common-mode capacitor C_Y4POne end, coil L_3a+One terminal sum-mode differential capacitor C_X4One end, coil L_3a+Another terminal, common mode capacitance C_Y7POne terminal sum-mode differential capacitor C_X7One end of the first phase positive electrode is connected with the first phase positive electrode output end of the multiplexing EMI filter, and the differential mode capacitor C_X7Another terminal, common mode capacitance C_Y7NOne end and a coil L_3a-One end of the first phase is connected with the second phase of the electromagnetic interference (EMI) filter to serve as a first phase cathode output end of the multiplexing EMI filter, and the coil L_3a-The other end is simultaneously connected with a differential mode capacitor C_X4Another terminal, common mode capacitance C_Y4NOne end and a coil L_2a-One end, coil L_2a-The other end is simultaneously connected with a differential mode capacitor C_X1Another terminal, common mode capacitance C_Y1NOne end and a coil L_1a-One end, coil L_1a-Another end, coil L_1c-One end and a coil L_1b-One end of the first and second filters is connected together to be used as the cathode output end of the multiplexing EMI filter,

coil L_1b-The other end is simultaneously connected with a differential mode capacitor C_X2One terminal, common mode capacitance C_Y2NOne end and a coil L_2b-One end, coil L_2b-The other end is simultaneously connected with a differential mode capacitor C_X5One terminal, common mode capacitance C_Y5NOne end and a coil L_3b-One end, coil L_3b-Another terminal, differential mode capacitance C_X8One terminal and a common mode capacitor C_Y8NOne end of the differential mode capacitor C is connected together to be used as a second phase negative input end of the multiplexing EMI filter_X8Another terminal, common mode capacitance C_Y8POne end and a coil L_3b+One end of the first phase is connected together to be used as a second phase anode output end of the multiplexing EMI filter, and the coil L_3b+The other end is simultaneously connected with a differential mode capacitor C_X5Another terminal, common mode capacitance C_Y5POne end and a coil L_2b+One end, coil L_2b+The other end is simultaneously connected with a differential mode capacitor C_X2Another terminal, common mode capacitance C_Y2POne end of (1) and a coil L_1b+The other end of the first tube is provided with a first end,

Coil L_1a+One end and a coil L_1b+One end of the input signal is respectively used as two alternating current signal input ends of the multiplexing EMI filter,

coil L_1a+The other end is simultaneously connected with a common-mode capacitor C_Y1POne end, coil L_2a+One terminal sum-mode differential capacitor C_X1One end, coil L_2a+The other end is simultaneously connected with a common-mode capacitor C_Y4POne end, coil L_3a+One terminal sum-mode differential capacitor C_X4One end, coil L_3a+Another terminal, common mode capacitance C_Y7POne terminal sum-mode differential capacitor C_X7One end of each of the first and second phase positive output terminals is connected together to serve as a first phase positive output terminal of the multiplexing EMI filter,

coil L_1b+The other end is connected with the coil L simultaneously_2b+One terminal, differential mode capacitance C_X2One terminal and a common mode capacitor C_Y2POne end of (1), coil L_2b+The other end is simultaneously connected with a differential mode capacitor C_X5One terminal, common mode capacitance C_Y5POne end and a coil L_3b+One end, coil L_3b+Another terminal, common mode capacitance C_Y8POne terminal sum-mode differential capacitor C_X8One end of each of the first and second phase positive outputs is connected together as a second phase positive output of the multiplexed EMI filter,

differential mode capacitor C_X1The other end is connected with a differential mode capacitor C_X2The other end, a differential mode capacitor C_X4The other end is connected with a differential mode capacitor C_X5The other end, a differential mode capacitor C_X7The other end is connected with a differential mode capacitor C_X8The other end of the first tube is provided with a first end,

common mode capacitor C_Y7NOne end and a coil L_3a-One end is connected withTogether as a first phase negative input terminal of a multiplexed EMI filter, coil L_3a-The other end is simultaneously connected with a common-mode capacitor C_Y4NOne end and a coil L_2a-One end, coil L_2a-The other end is simultaneously connected with a common-mode capacitor C_Y1NOne end and a coil L_1a-One end, coil L_1a-Another end, coil L_1b-One end and a coil L_1c-One end of the first and second filters is connected together to be used as a negative output end of the multiplexing EMI filter,

coil L_1b-The other end is simultaneously connected with a common-mode capacitor C_Y2NOne end and a coil L_2b-One end, coil L_2b-The other end is simultaneously connected with a common-mode capacitor C_Y5NOne end and a coil L_3b-One end, coil L_3b-The other end and a common-mode capacitor C_Y8NOne end of the first phase is connected together to be used as a second phase negative input end of the multiplexing EMI filter,

coil L_1c-The other end is simultaneously connected with a differential mode capacitor C_X3One terminal, common mode capacitance C_Y3NOne end and a coil L_2c-One end, coil L_2c-The other end is simultaneously connected with a differential mode capacitor C_X6One terminal, common mode capacitance C_Y6NOne end and a coil L_3c-One end, coil L_3c-The other end and a differential mode capacitor C_X9One end of the first phase is connected together to be used as a third phase negative input end of the multiplexing EMI filter,

coil L_3c+One terminal, differential mode capacitance C_X9The other end and a common-mode capacitor C_Y9POne end of the first phase is connected together to be used as a third phase positive input end of the multiplexing EMI filter, and the coil L_3c+The other end is simultaneously connected with a differential mode capacitor C_X6Another terminal, common mode capacitance C_Y6POne end and a coil L_2c+One end, coil L_2c+The other end is simultaneously connected with a differential mode capacitor C_X3Another terminal, common mode capacitance C_Y3POne end and a coil L_1c+One end, coil L_1c+The other end is used as the anode input end of the multiplexing EMI filter,

The invention has the beneficial effects that:

the multiplexing EMI filter provided by the application comprises three coupling inductors, 18 common-mode capacitors and 9 differential-mode capacitors. When the electric automobile integrated system works in a driving mode, the multiplexed EMI filter suppresses system noise for the motor driver. The three coupling inductors are used as common mode inductors, leakage inductors of the three coupling inductors are used as differential mode inductors, and meanwhile, the positive electrode of each phase of the three-phase interleaved Boost converter uses 3 common mode capacitors, and the negative electrode of each phase of the three-phase interleaved Boost converter uses 3 common mode capacitors and 3 differential mode capacitors.

When the electric automobile integrated system works in a charging mode, the multiplexed EMI filter suppresses system noise for an OBC (on-board battery charger). The grid-side EMI filter behaves as: two groups of coils of a three-phase coupling inductor are multiplexed to be used as an EMI filter common mode inductor input by a single-phase network side, leakage inductors of the two groups of coils are used as differential mode inductors, 6 capacitors between two power lines on the network side are multiplexed to be used as common mode capacitors, and corresponding differential mode capacitors are multiplexed to be used as differential mode capacitors on the network side after being connected in series. The battery-side EMI filter behaves as: a group of coils corresponding to the positive pole of the battery and three groups of coils corresponding to the negative pole of the battery are multiplexed to be used as common mode inductors, leakage inductors of the three coupled inductors are used as differential mode inductors, 9 capacitors with the negative pole facing the ground are multiplexed to be used as common mode capacitors, and the rest 3 capacitors are multiplexed to be used as differential mode capacitors. The integrated EMI filter provided by the invention realizes the functions of two groups of EMI filters of an electric automobile integrated system OBC and one group of EMI filters of a motor driver by using the same set of hardware, and greatly improves the power density of the system.

Therefore, the denoising function of the electric automobile integrated system in different working modes is realized by using the same set of EMI filter hardware, namely denoising the battery in a driving mode and denoising the power grid in a charging mode, and the problem of power density reduction caused by excessive EMI filters needed by the electric automobile integrated system in different working modes is solved.

Drawings

FIG. 1 is a schematic diagram of an integrated system of a conventional electric vehicle;

FIG. 2 is a schematic diagram of a conventional electric vehicle integrated system operating in a driving mode;

FIG. 3 is a schematic diagram of a conventional electric vehicle integrated system operating in a charging mode;

FIG. 4 is a schematic diagram of a multiplexed EMI filter for an electric vehicle integrated system of the present application;

FIG. 5 is a schematic diagram of an electric vehicle integration system of the present application operating in a drive mode;

fig. 6 is a schematic diagram of the electric vehicle integrated system according to the present application operating in a charging mode.

Detailed Description

The first embodiment is as follows: the embodiment is described with reference to fig. 4, and the multiplexing EMI filter according to the embodiment is applied to an electric vehicle integrated system, and includes switches K1-K2, three coupling inductors, 18 common-mode capacitors and 9 differential-mode capacitors,

One end of a switch K1, one end of a switch K2 and a coil L_1c+One end of the switch K1 is connected with the other end of the switch K1 and the coil L together to be used as the positive input end of the multiplexing EMI filter_1a+One end of the coil L is connected together to be used as an alternating current signal input end of the multiplexing EMI filter_1a+The other end is simultaneously connected with a common-mode capacitor C_Y1POne end, coil L_2a+One terminal sum-mode differential capacitor C_X1One end, coil L_2a+The other end is simultaneously connectedCommon mode capacitor C_Y4POne end, coil L_3a+One terminal sum-mode differential capacitor C_X4One end, coil L_3a+Another terminal, common mode capacitance C_Y7POne terminal sum-mode differential capacitor C_X7One end of the first phase positive electrode is connected with the first phase positive electrode output end of the multiplexing EMI filter, and the differential mode capacitor C_X7Another terminal, common mode capacitance C_Y7NOne end and a coil L_3a-One end of the first phase is connected with the second phase of the electromagnetic interference (EMI) filter to serve as a first phase cathode output end of the multiplexing EMI filter, and the coil L_3a-The other end is simultaneously connected with a differential mode capacitor C_X4Another terminal, common mode capacitance C_Y4NOne end and a coil L_2a-One end, coil L_2a-The other end is simultaneously connected with a differential mode capacitor C_X1Another terminal, common mode capacitance C_Y1NOne end and a coil L_1a-One end, coil L_1a-Another end, coil L_1c-One end and a coil L_1b-One end of the first and second filters is connected together to be used as the cathode output end of the multiplexing EMI filter,

coil L_1b-The other end is simultaneously connected with a differential mode capacitor C_X2One terminal, common mode capacitance C_Y2NOne end and a coil L_2bOne end, coil L_2bThe other end is simultaneously connected to a differential-mode capacitor C_X5One terminal, common mode capacitance C_Y5NOne end and a coil L_3bOne end, coil L_3bThe other terminal, a differential mode capacitance C_X8One terminal and a common mode capacitor C_Y8NOne end of the differential mode capacitor C is connected together to be used as a second phase negative input end of the multiplexing EMI filter_X8Another terminal, common mode capacitance C_Y8POne end and a coil L_3b+One end of the first phase is connected together to be used as a second phase anode output end of the multiplexing EMI filter, and the coil L_3b+The other end is simultaneously connected with a differential mode capacitor C_X5Another terminal, common mode capacitance C_Y5POne end and a coil L_2b+One end, coil L_2b+The other end is simultaneously connected with a differential mode capacitor C_X2Another terminal, common mode capacitance C_Y2POne end of (1) and a coil L_1b+One end, coil L_1b+The other end is connected with the switch K2 to be used as the other alternating current signal input end of the multiplexing EMI filter,

coil L_1c+The other end is simultaneously connectedDifferential mode capacitance C_X3One terminal, common mode capacitance C_Y3POne end and a coil L_2cOne end, coil L_2cThe other end is simultaneously connected to a differential-mode capacitor C_X6One terminal, common mode capacitance C_Y6POne end and a coil L_3cOne end, coil L_3c-The other end is simultaneously connected with a differential mode capacitor C_X9One terminal and a common mode capacitor C_Y9POne end of the differential mode capacitor C is connected with the third phase positive electrode output end of the multiplexing EMI filter_X9Another terminal, common mode capacitance C_Y9NOne end and a coil L_3c-One end of the first phase is connected with the second phase as the third phase negative input end of the multiplexing EMI filter, and the coil L_3c-The other end is simultaneously connected with a differential mode capacitor C_X6Another terminal, common mode capacitance C_Y6NOne end and a coil L_2c-One end, coil L_2c-The other end is simultaneously connected with a differential mode capacitor C_X3Another terminal, common mode capacitance C_Y3NOne end and a coil L_1c-The other end of the first tube is provided with a first end,

In this embodiment, when the multiplexing EMI filter operates in the driving mode, the multiplexing converter realizes a function of a three-phase interleaved Boost converter, including a Boost1 (a first Boost converter), a Boost2 (a second Boost converter), and a Boost3 (a third Boost converter), as specifically shown in fig. 2. In order to reduce the EMI of the motor driver, an EMI filter is added between the battery of the electric vehicle and the multiplexing converter to suppress noise. When the multiplexing EMI filter works in a charging mode, the Boost1 and the Boost2 of the multiplexing converter are used as two-phase bridge arms of controllable rectification at the moment to realize the functions of correcting the power factor and adjusting the voltage of a direct current bus, and the Boost3 of the multiplexing converter is used as a DC/DC converter to realize the function of adjusting the charging voltage of the battery of the electric automobile. In order to reduce the EMI of the OBC, it is necessary to add an EMI filter 1 between the single-phase grid input side and the multiplexed controllable rectifier bridge to eliminate the noise interference on the grid side, and it is also necessary to add an EMI filter 2 between the battery side of the electric vehicle and the multiplexed DC/DC converter to eliminate the noise interference on the battery side, as shown in fig. 3. Therefore, when the electric automobile integrated system works in a driving mode and a charging mode, 3 EMI filters are needed to realize the EMI suppression of the integrated system, the 3 EMI filters occupy a large amount of space, the weight of the system is increased, and the power density of the system is reduced. Therefore, the invention provides an EMI filter integration scheme, which integrates 3 EMI filters required by an electric automobile integration system, saves system space, reduces weight and improves power density of the system.

Fig. 4 is a general block diagram of an EMI filter integration scheme according to the present invention. L1, L2 and L3 are three coupling inductors used by the integrated filter, each coupling inductor is formed by winding three groups of coils, and the coils of the three coupling inductors can be marked as L according to the positive and negative poles of a connected loop_1a+、L_1b+、L_1c+、L_1a-、L_1b-、L_1c-、L_2a+、L_2b+、L_2c+、L_2a-、L_2b-、L_2c-、L_3a+、L_3b+、L_3c+、L_3a-、L_3b-、L_3c-. The common mode Y capacitor can be marked as C according to the positive and negative poles of the loop_Y1P、C_Y2P、C_Y3P、C_Y4P、C_Y5P、C_Y6P、C_Y7P、C_Y8P、C_Y9P、C_Y1N、C_Y2N、C_Y3N、C_Y4N、C_Y5N、C_Y6N、C_Y7N、C_Y8N、C_Y9NDifferential mode X capacitor labeled C_X1、C_X2、C_X3、C_X4、C_X5、C_X6、C_X7、C_X8、C_X9. Coupling inductance coil L_1a+、L_1b+Two switches K1 and K2 are connected in series with the battery of the electric vehicle, so that the working mode of the integrated EMI filter can be changed.

When the electric vehicle integrated system operates in the driving mode, the switches K1 and K2 are closed, and the equivalent circuit diagram of the EMI filter is shown in fig. 5. Common mode inductance of the EMI filter of the motor driver is self-inductance of L1, L2 and L3, and a coil L_1a+、L_1b+、L_1c+、L_2a+、L_2b+、L_2c+、L_3a+、L_3b+、L_3c+Common mode inductance being the positive pole of the bus, coil L_1a-、L_1b-、L_1c-、L_2a-、L_2b-、L_2c-、L_3a-、L_3b-、L_3c-Common mode inductance being the negative pole of the bus, L₁、L₂And L₃The leakage inductance is the differential mode inductance of the EMI filter. The common mode capacitance of the bus anode of the EMI filter is C_Y1P、C_Y2P、C_Y3P、C_Y4P、C_Y5P、C_Y6P、C_Y7P、C_Y8P、C_Y9PThe common-mode capacitance of the negative pole of the bus is C_Y1N、C_Y2N、C_Y3N、C_Y4N、C_Y5N、C_Y6N、C_Y7N、C_Y8N、C_Y9NDifferential mode capacitance of C_X1、C_X2、C_X3、C_X4、C_X5、C_X6、C_X7、C_X8、C_X9. Common mode capacitance and common mode inductance are used to attenuate common mode noise, and differential mode capacitance and differential mode inductance (including leakage inductance of the common mode inductor) are used to attenuate differential mode noise. The inductor presents a high impedance to high frequency noise and reflects or absorbs the noise, while the capacitor acts as a low impedance path to common ground, shunting the noise away from the main circuit. Since the differential mode interference of the multiplexing converter system already meets the EMI standard limit, a separate differential mode inductor is not arranged, and the leakage inductance of the common mode inductor and the differential mode capacitance are utilized to further reduce the differential mode EMI level. The common mode inductor is connected with the positive pole and the negative pole of the bus and is composed of coils with the same number of turns, magnetic fluxes generated by currents in the positive pole and the negative pole coils are equal in magnitude and opposite in phase, and the magnetic fluxes are mutually offset to enable the magnetic core to be in an unbiased state.

When the electric vehicle integrated system operates in the charging mode, the switches K1 and K2 are opened, and the equivalent circuit diagram of the EMI filter is shown in fig. 6, and the EMI filter of the OBC includes the grid-side EMI filter 1 and the battery-side EMI filter 2. The common mode inductor of the EMI filter 1 is connected with the positive pole of the network side by a coil L_1a+、L_2a+、L_3a+Connected to the negative electrode is a coil L_1b+、L_2b+、L_3b+Differential mode inductance is coil L_1a+、L_2a+、L_3a+And a coil L_1b+、L_2b+、L_3b+And a leakage inductance therebetween. The common mode capacitance of the EMI filter power grid anode is C_Y1P、C_Y4P、C_Y7PThe common-mode capacitance of the negative electrode of the power grid is C_Y2P、C_Y5P、C_Y8PDifferential mode capacitance of C_X1And C_X2Series connection, C_X4And C_X5Series connection, C_X7And C_X8Are connected in series. The common mode inductor of the EMI filter 2 is connected with the anode of the battery and is a coil L_1c+、L_2c+、L_3c+Connected to the negative pole of the battery are three sets of coils (L)_1a-、L_2a-、L_3a+)，(L_1b-、L_2b-、L_3b-)，(L_1c+、L_2c-、L_3c-). The common mode capacitance of the battery anode is C_Y3P、C_Y4P、C_Y9NThe common-mode capacitance of the negative electrode of the battery is C_Y1N、C_Y2N、C_Y3N、C_Y4N、C_Y5N、C_Y6N、C_Y7N、C_Y8N、C_Y9NDifferential mode capacitance of C_X3、C_X6、C_X9. According to the kirchhoff's law of current, the common mode inductance and the magnetic flux generated by the currents in the positive and negative coils of the battery are equal in magnitude and opposite in phase, and the magnetic fluxes are mutually offset to enable the magnetic core to be in an unbiased state.

By utilizing the integrated EMI filter provided by the application, the integrated system of the electric automobile can provide a battery side EMI filter for a motor driver in a driving mode; in the charging mode, two sets of EMI filters may be provided for the OBC on the network side and the battery side. The electric automobile integrated system is guaranteed to meet the international EMI requirement, the system space can be saved, the weight can be reduced, and the power density can be provided.

The second embodiment is as follows: this embodiment is the multiplexed EMI filter of the first embodiment, further comprising a controller,

The third concrete implementation mode: the embodiment is described with reference to fig. 5, the multiplexing EMI filter according to the embodiment is applied to an integrated system of an electric vehicle, the multiplexing EMI filter includes three coupling inductors, 18 common mode capacitors and 9 differential mode capacitors,

Coil L_1a+One end, coil L_1b+One end and a coil L_1c+One end of the coil L is connected together to be used as the positive input end of the multiplexing EMI filter_1a+The other end is simultaneously connected with a common-mode capacitor C_Y1POne end, coil L_2a+One terminal sum-mode differential capacitor C_X1One end, coil L_2a+The other end is simultaneously connected with a common-mode capacitor C_Y4POne end, coil L_3a+One terminal sum-mode differential capacitor C_X4One end, coil L_3a+Another terminal, common mode capacitance C_Y7POne terminal sum-mode differential capacitor C_X7One end of the first phase positive electrode is connected with the first phase positive electrode output end of the multiplexing EMI filter, and the differential mode capacitor C_X7Another terminal, common mode capacitance C_Y7NOne end and a coil L_3a-One end of the first phase is connected with the second phase of the electromagnetic interference (EMI) filter to serve as a first phase cathode output end of the multiplexing EMI filter, and the coil L_3a-The other end is simultaneously connected with a differential mode capacitor C_X4Another terminal, common mode capacitance C_Y4NOne end and a coil L_2a-One end, coil L_2a-The other end is the same asTime-connected differential mode capacitor C_X1Another terminal, common mode capacitance C_Y1NOne end and a coil L_1a-One end, coil L_1a-Another end, coil L_1c-One end and a coil L_1b-One end of the first and second filters is connected together to be used as the cathode output end of the multiplexing EMI filter,

The fourth concrete implementation mode: the embodiment is described with reference to fig. 6, and the multiplexing EMI filter according to the embodiment is applied to an electric vehicle integrated system, and includes three coupling inductors, 18 common mode capacitors and 9 differential mode capacitors,

coil L_1b+The other end is connected with the wire simultaneouslyRing L_2b+One terminal, differential mode capacitance C_X2One terminal and a common mode capacitor C_Y2POne end of (1), coil L_2b+The other end is simultaneously connected with a differential mode capacitor C_X5One terminal, common mode capacitance C_Y5POne end and a coil L_3b+One end, coil L_3b+Another terminal, common mode capacitance C_Y8POne terminal sum-mode differential capacitor C_X8One end of each of the first and second phase positive outputs is connected together as a second phase positive output of the multiplexed EMI filter,

common mode capacitor C_Y7NOne end and a coil L_3a-One end of the first phase is connected together to be used as a first phase negative electrode input end of the multiplexing EMI filter, and the coil L_3a-The other end is simultaneously connected with a common-mode capacitor C_Y4NOne end and a coil L_2a-One end, coil L_2a-The other end is simultaneously connected with a common-mode capacitor C_Y1NOne end and a coil L_1a-One end, coil L_1a-Another end, coil L_1b-One end and a coil L_1c-One end of the first and second filters is connected together to be used as a negative output end of the multiplexing EMI filter,

coil L_1c-The other end is simultaneously connected with a differential mode capacitor C_X3One terminal, common mode capacitance C_Y3NOne end and a coil L_2c-One end, coil L_2c-The other end is simultaneously connected with a differential mode capacitor C_X6One terminal, common mode capacitance C_Y6NOne end and a coil L_3c-One end, coil L_3c-The other end and a differential mode capacitor C_X9Third phase with one end connected together as a multiplexed EMI filterAn input end of the negative electrode is provided,

In this embodiment, as shown in fig. 4, the three coupling inductors include a coupling inductor L₁Coupled inductor L₂And a coupling inductor L₃Loop L of_1a+Coil L_1a-Coil L_1b+Coil L_1b-Coil L_1c+And a coil L_1c-Form a coupling inductor L₁Loop L of_2a+Coil L_2a-Coil L_2b+Coil L_2b-Coil L_2c+And a coil L_2c-Form a coupling inductor L₂Loop L of_3a+Coil L_3a-Coil L_3b+Coil L_3b-Coil L_3c+And a coil L_3c-Form a coupling inductor L₃，

The benefit of using three coupled inductors in fig. 4 is:

1. on the circuit board structure of multiplexing EMI wave filter, there are the inductance of three boost converter on the circuit board, and the inside coupling inductance that can place a multiplexing EMI wave filter of inductance of every boost converter sets up 3 coupling inductances altogether, if the inside coupling inductance that all places a multiplexing EMI wave filter of inductance of every three boost converter, can make full use of the inner space of three boost converter inductance, avoids the space idle, extravagant space.

2. The noise suppression effect is better with 3 coupled inductors than with 1 coupled inductor or 2 coupled inductors.

3. The volume of three cascaded inductors is smaller than that of one inductor when the suppression capacity is the same.

Claims

1. The multiplexing EMI filter is applied to an electric automobile integrated system and is characterized by comprising switches K1-K2, three coupling inductors, 18 common-mode capacitors and 9 differential-mode capacitors,

the three coupled inductors comprise a coil L_1a+Coil L_1a-, coil L_2a+Coil L_2a-Coil L_3a+Coil L_3a-Coil L_1b+Coil L_1b-Coil L_2b+Coil L_2b-Coil L_3b+Coil L_3b-Loop L of_1c+Coil L_1c-Coil L_2c+Coil L_2c-Coil L_3c+And a coil L_3c-，

One end of a switch K1, one end of a switch K2 and a coil L_1c+One end of the switch K1 is connected with the other end of the switch K1 and the coil L together to be used as the positive input end of the multiplexing EMI filter_1a+One end of the coil L is connected together to be used as an alternating current signal input end of the multiplexing EMI filter_1a+The other end is simultaneously connected with a common-mode capacitor C_Y1POne end, coil L_2a+One terminal sum-mode differential capacitor C_X1One end, coil L_2a+The other end is simultaneously connected with a common-mode capacitor C_Y4POne end, coil L_3a+One terminal sum-mode differential capacitor C_X4One end, coil L_3a+Another terminal, common mode capacitance C_Y7POne terminal sum-mode differential capacitor C_X7One end of the first phase positive electrode is connected with the first phase positive electrode output end of the multiplexing EMI filter, and the differential mode capacitor C_X7Another terminal, common mode capacitance C_Y7NOne end and a coil L_3a-One end is connected toConnected together as a first phase negative output terminal of a multiplexed EMI filter, coil L_3a-The other end is simultaneously connected with a differential mode capacitor C_X4Another terminal, common mode capacitance C_Y4NOne end and a coil L_2a-One end, coil L_2a-The other end is simultaneously connected with a differential mode capacitor C_X1Another terminal, common mode capacitance C_Y1NOne end and a coil L_1a-One end, coil L_1a-Another end, coil L_1cOne end and a coil L_1b-one terminal each connected together as a negative output terminal of the multiplexed EMI filter,

coil L_1bThe other end is simultaneously connected to a differential-mode capacitor C_X2One terminal, common mode capacitance C_Y2NOne end and a coil L_2bOne end, coil L_2bThe other end is simultaneously connected to a differential-mode capacitor C_X5One terminal, common mode capacitance C_Y5NOne end and a coil L_3b-One end, coil L_3b-Another terminal, differential mode capacitance C_X8One terminal and a common mode capacitor C_Y8NOne end of the differential mode capacitor C is connected together to be used as a second phase negative input end of the multiplexing EMI filter_X8Another terminal, common mode capacitance C_Y8POne end and a coil L_3b+One end of the first phase is connected together to be used as a second phase anode output end of the multiplexing EMI filter, and the coil L_3b+The other end is simultaneously connected with a differential mode capacitor C_X5Another terminal, common mode capacitance C_Y5POne end and a coil L_2b+One end, coil L_2b+The other end is simultaneously connected with a differential mode capacitor C_X2Another terminal, common mode capacitance C_Y2POne end of (1) and a coil L_1b+One end, coil L_1b+The other end is connected with the switch K2 to be used as the other alternating current signal input end of the multiplexing EMI filter,

coil L_1c+The other end is simultaneously connected with a differential mode capacitor C_X3One terminal, common mode capacitance C_Y3POne end and a coil L_2c-One end, coil L_2c-The other end is simultaneously connected with a differential mode capacitor C_X6One terminal, common mode capacitance C_Y6POne end and a coil L_3c-One end, coil L_3c-The other end is simultaneously connected with a differential mode capacitor C_X9One terminal and a common mode capacitor C_Y9POne end of each of the two terminals is connected together as a multiplexThe third phase positive output end of the EMI filter and a differential mode capacitor C_X9Another terminal, common mode capacitance C_Y9NOne end and a coil L_3c-One end of the first phase is connected with the second phase as the third phase negative input end of the multiplexing EMI filter, and the coil L_3c-The other end is simultaneously connected with a differential mode capacitor C_X6Another terminal, common mode capacitance C_Y6NOne end and a coil L_2c-One end, coil L_2c-The other end is simultaneously connected with a differential mode capacitor C_X3Another terminal, common mode capacitance C_Y3NOne end and a coil L_1c-The other end of the first tube is provided with a first end,

2. The multiplexed EMI filter of claim 1, further comprising a controller,

3. The multiplexing EMI filter is applied to an electric automobile integrated system and is characterized by comprising three coupling inductors, 18 common-mode capacitors and 9 differential-mode capacitors,

Coil L_1a+One end, coil L_1b+One end of the wireRing L_1c+One end of the coil L is connected together to be used as the positive input end of the multiplexing EMI filter_1a+The other end is simultaneously connected with a common-mode capacitor C_Y1POne end, coil L_2a+One terminal sum-mode differential capacitor C_X1One end, coil L_2a+The other end is simultaneously connected with a common-mode capacitor C_Y4POne end, coil L_3a+One terminal sum-mode differential capacitor C_X4One end, coil L_3a+Another terminal, common mode capacitance C_Y7POne terminal sum-mode differential capacitor C_X7One end of the first phase positive electrode is connected with the first phase positive electrode output end of the multiplexing EMI filter, and the differential mode capacitor C_X7Another terminal, common mode capacitance C_Y7NOne end and a coil L_3a-One end of the first phase is connected with the second phase of the electromagnetic interference (EMI) filter to serve as a first phase cathode output end of the multiplexing EMI filter, and the coil L_3a-The other end is simultaneously connected with a differential mode capacitor C_X4Another terminal, common mode capacitance C_Y4NOne end and a coil L_2a-One end, coil L_2a-The other end is simultaneously connected with a differential mode capacitor C_X1Another terminal, common mode capacitance C_Y1NOne end and a coil L_1a-One end, coil L_1a-Another end, coil L_1c-One end and a coil L_1b-One end of the first and second filters is connected together to be used as the cathode output end of the multiplexing EMI filter,

coil L_1b-The other end is simultaneously connected with a differential mode capacitor C_X2One terminal, common mode capacitance C_Y2NOne end and a coil L_2b-One end, coil L_2b-The other end is simultaneously connected with a differential mode capacitor C_X5One terminal, common mode capacitance C_Y5NOne end and a coil L_3b-One end, coil L_3b-Another terminal, differential mode capacitance C_X8One terminal and a common mode capacitor C_Y8NOne end of the differential mode capacitor C is connected together to be used as a second phase negative input end of the multiplexing EMI filter_X8Another terminal, common mode capacitance C_Y8POne end and a coil L_3b+One end of the first phase is connected together to be used as a second phase anode output end of the multiplexing EMI filter, and the coil L_3b+The other end is simultaneously connected with a differential mode capacitor C_X5Another terminal, common mode capacitance C_Y5POne end and a coil L_2b+One end, coil L_2b+The other end is simultaneously connected with a differential mode capacitor C_X2Another one isTerminal and common mode capacitor C_Y2POne end of (1) and a coil L_1b+The other end of the first tube is provided with a first end,

4. The multiplexing EMI filter is applied to an electric automobile integrated system and is characterized by comprising three coupling inductors, 18 common-mode capacitors and 9 differential-mode capacitors,

common mode capacitor C_Y7NOne end and a coil L_3a-One end of the first phase is connected together to be used as a first phase negative electrode input end of the multiplexing EMI filter, and the coil L_3a-The other end is simultaneously connected with a common-mode capacitor C_Y4NOne end and a coil L_2a-One end, coil L_2a-The other end is simultaneously connected with a common-mode capacitor C_Y1NOne end and a coil L_1a-One end, coil L_1a-Another end, coil L_1b-One end and a coil L_1c-One end is connected togetherAs the negative output terminal of the multiplexing EMI filter,