CN220022607U - Common-mode voltage and common-mode current suppressing circuit - Google Patents

Abstract

The utility model provides a common-mode voltage and common-mode current suppression circuit which comprises an alternating current/direct current power module, an alternating current side filter with a first alternating current side filter capacitor and a direct current side support capacitor, wherein a direct current side common-mode reflux capacitor is arranged on the direct current side of the alternating current/direct current power module, and a virtual neutral point of the first alternating current side filter capacitor is connected with the middle point of the direct current side common-mode reflux capacitor; or an alternating current side common mode inductor is arranged between the alternating current side of the alternating current/direct current power module and the alternating current side filter, and the virtual neutral point of the first alternating current side filter capacitor is connected with the middle point of the direct current side supporting capacitor. The common-mode voltage and common-mode current suppression circuit without an isolation transformer can effectively reduce the common-mode voltage and common-mode current of a power electronic converter, omits the isolation transformer, reduces the cost, reduces the volume and improves the efficiency.

Description

Common-mode voltage and common-mode current suppressing circuit

[ field of technology ]

The utility model relates to the technical field of power supply circuits, in particular to a common-mode voltage and common-mode current suppression circuit.

[ background Art ]

PWM rectifiers or inverters (hereinafter collectively referred to as power electronic converters) generally employ semiconductor switching devices (e.g., IGBT, MOSFET, SIC, GAN, etc.) to form a main circuit, and by controlling the operating states of the switching devices, conversion of electrical energy can be achieved. However, when the switching device is switched at a high speed, the power electronic converter has very large common mode interference, and the common mode interference is more serious for a high-power converter. Common mode voltages and currents pose a serious hazard to power electronics and power systems. Which can lead to breakdown damage of components in the device, interfere with signal measurement of the device, interfere with communication of the device; for energy storage systems connected to the battery, common mode voltages that are not attenuation suppressed can interfere with the battery's BMS management system and even damage the battery; for systems connected to generators, the common mode voltage can interfere with the excitation system of the generator; for a transmission system connected with a motor, common-mode voltage can cause insulation failure or damage of a motor winding, and larger bearing current is generated through a coupling capacitor of the motor to the ground, so that the motor is damaged due to overlarge bearing current; for a system connected with the power grid, common mode voltage and common mode current can enter the power grid, so that harmonic pollution is caused to the power grid, and normal operation of other equipment in the power grid is affected. Particularly for an energy storage system and a photovoltaic power generation system in the field of new energy, the alternating current side of the system is connected with a power grid, and the direct current side of the system is connected with an energy storage battery or a solar panel. Because the energy storage battery and the solar panel have larger distributed capacitance to the ground, the common-mode voltage generated during the operation of the energy storage converter directly affects the battery and the power grid. Therefore, how to reduce the common mode voltage and current has been a critical technical problem that needs to be resolved urgently in the industry.

The prior art proposes four general solutions to the related problems, referring to fig. 1, fig. 1 is a schematic diagram of a conventional common-mode voltage and common-mode current suppressing circuit. One-to-one discussion is provided herein.

Scheme one: referring to fig. 1a, the common-mode voltage and common-mode current suppressing circuit includes an ac/dc power module 11, an ac side filter 3 having a first ac side filter capacitor C1, and a dc side supporting capacitor C2. In the scheme I, a power frequency isolation transformer is arranged on the alternating current side to isolate the influence of a common mode voltage on the alternating current side. The industrial frequency isolation transformer has large volume, heavy weight and high cost, so that the application range of the scheme is limited. In addition, although the isolation transformer is arranged on the ac side, the influence of the common-mode voltage on the ac side can be effectively suppressed, but the common-mode voltage on the dc side cannot be suppressed well.

Scheme II: referring to fig. 1b, the scheme configures a large-capacity grounding capacitor CY to the ground on the ac side. Although the common-mode voltage at the ac side can be filtered, there is a large leakage current, and the common-mode voltage at the dc side cannot be suppressed. The system having the ground-fault insulation monitoring function and the system having the battery connected to the direct current terminal cannot be applied due to the large ground fault current.

Scheme III: referring to fig. 1c, the scheme configures a large grounding capacitor CY on the dc side. Although the scheme can filter the common-mode voltage of the direct-current end, larger ground leakage current exists, and the common-mode voltage interference on the alternating-current side when the converter works cannot be restrained, so that the scheme is not applicable.

Scheme IV: referring to fig. 1d, the scheme shorts the virtual neutral point of the ac filter 3 with the midpoint of the dc bus supporting capacitor C2, and provides a low-impedance common-mode return path for the common-mode current. The common-mode voltage on the alternating current side and the common-mode voltage on the direct current side are well inhibited, and the common-mode voltage on the alternating current side and the common-mode voltage on the direct current side are widely applied to PWM rectifiers or inverters with small power levels at present. For a medium-high power PWM rectifier or inverter, the current in the common mode return path in the system is very large, so that the scheme cannot be directly applied to the medium-high power PWM rectifier or inverter.

[ utility model ]

The common-mode voltage and common-mode current suppression circuit provided by the utility model is used for solving the technical problems of large volume, heavy weight, high cost, low efficiency, insufficient safety performance and the like.

The common mode voltage and common mode current suppressing circuit comprises an alternating current/direct current power module, an alternating current side filter with a first alternating current side filter capacitor and a direct current side supporting capacitor, wherein the alternating current side filter is arranged on the alternating current side of the alternating current/direct current power module, the direct current side supporting capacitor is arranged on the direct current side of the alternating current/direct current power module, a direct current side common mode reflux capacitor is arranged on the direct current side of the alternating current/direct current power module, a virtual neutral point of the first alternating current side filter capacitor is connected with a midpoint of the direct current side common mode reflux capacitor, or an alternating current side common mode inductor is arranged between the alternating current side of the alternating current/direct current power module and the alternating current side filter, and the virtual neutral point of the first alternating current side filter capacitor is connected with the midpoint of the direct current side supporting capacitor to form a common mode current reflux path so as to provide a common mode current with a common mode low-pass filter path inside a system.

Compared with the prior art, the common-mode voltage and common-mode current suppression circuit provided by the utility model has the advantages that the virtual neutral point of the first alternating-current side filter capacitor is connected with the middle point of the direct-current side common-mode reflux capacitor by introducing the direct-current side common-mode reflux capacitor into the direct-current side, or the virtual neutral point of the first alternating-current side filter capacitor is connected with the middle point of the direct-current side support capacitor into the alternating-current side common-mode inductor, so that a common-mode current reflux path is formed, and a common-mode low-pass filter path in a system is provided for common-mode current, so that common-mode voltage and common-mode current are suppressed. The utility model not only omits an isolation transformer, reduces the cost, reduces the volume and improves the efficiency, but also effectively inhibits the common-mode voltage and the common-mode current of the alternating current side and the direct current side.

In addition, the direct-current side common-mode reflux capacitor and the alternating-current side common-mode inductance parameter can be adjusted, and the direct-current side common-mode reflux capacitor and the alternating-current side common-mode inductance parameter can be widely applied to energy storage systems with various power grades and various voltage grades, battery formation systems, photovoltaic power generation systems, micro-grids, motor transmission and other application scenes, and are wide in applicability.

[ description of the drawings ]

For a clearer description of the technical solutions of the embodiments of the present utility model, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the description below are only some embodiments of the present utility model, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art, wherein:

FIG. 1a is a schematic diagram of a prior art common mode voltage and common mode current rejection circuit scheme one;

FIG. 1b is a schematic diagram of a prior art common mode voltage and common mode current rejection circuit scheme two;

FIG. 1c is a schematic diagram of a prior art common mode voltage and common mode current rejection circuit scheme three;

FIG. 1d is a schematic diagram of a prior art common mode voltage and common mode current rejection circuit scheme IV;

FIG. 2 is a schematic diagram of a first embodiment of the common mode voltage and common mode current rejection circuit of the present utility model;

FIG. 3a is a schematic diagram of a second embodiment of the common mode voltage and current suppression circuit of the present application;

FIG. 3b is a schematic diagram of a third embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 4 is a schematic diagram of a fourth embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 5 is a schematic diagram of a fifth embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 6 is a schematic diagram of a sixth embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 7 is a schematic diagram of a seventh embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 8 is a schematic diagram of an eighth embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 9 is a schematic diagram of a ninth embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 10 is a schematic diagram of a tenth embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 11 is a schematic diagram of an eleventh embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 12 is a schematic diagram of a twelfth embodiment of the common mode voltage and common mode current rejection circuit of the present application;

FIG. 13 is a schematic diagram of a thirteenth embodiment of the common mode voltage and common mode current rejection circuit of the present application;

[ detailed description ] of the application

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Embodiment one:

referring to fig. 2 in combination, fig. 2 is a schematic diagram of a common mode voltage and common mode current suppressing circuit according to a first embodiment of the present utility model. The common mode voltage and common mode current suppressing circuit 10 includes an ac/dc power module 101, an ac side filter 103 having a first ac side filter capacitor 1C1, and a dc side support capacitor 1C2.

The ac side filter 103 is provided on the ac side of the ac/dc power module 101. The ac side filter 103 is in the form of an LC filter or an LCL filter, and in this example, the ac side filter 103 is in the form of an LCL filter, and further includes an inverter side inductor 1L1 and a distribution network side inductor 1L2, where the inverter side inductor 1L1 is close to the ac side of the ac/dc power module 101, and the first ac side filter capacitor 1C1 is disposed between the inverter side inductor 1L1 and the distribution network side inductor 1L 2. In another embodiment, the ac side filter 103 is in the form of an LC filter, and the other matters are identical and will not be described herein.

The direct current side supporting capacitor 1C2 is disposed on the direct current side of the ac/dc power module 101, the direct current side common mode reflux capacitor 1C3 is disposed on the direct current side of the ac/dc power module 101, and the virtual neutral point of the first ac side filtering capacitor 1C1 is connected with the midpoint of the direct current side common mode reflux capacitor 1C3 to form a common mode current reflux path, so as to provide a common mode low pass filtering path inside the system for the common mode current.

Meanwhile, a dc side common mode inductance 1L3 is provided on the dc side of the ac/dc power module 101 corresponding to the dc side common mode reflux capacitor 1C3, and the dc side common mode inductance 1L3 is provided between the dc side supporting capacitor 1C2 and the dc side common mode reflux capacitor 1C 3.

In this embodiment, by selecting appropriate parameters of the first ac side filter capacitor 1C1, the dc side common mode inductor 1L3, and the dc side common mode reflux capacitor 1C3, the common mode voltage on the ac side and the common mode voltage on the dc side can be suppressed to the allowable range of the system, and the common mode current on the ac side to ground and the common mode current on the dc side outside the system can be effectively reduced, so as to achieve the objective of suppressing the common mode voltage and the common mode current without isolating a transformer.

Embodiment two and embodiment three:

referring to fig. 3a and fig. 3b in combination, fig. 3a is a schematic diagram of a second embodiment of the common-mode voltage and common-mode current suppressing circuit of the present application, and fig. 3b is a schematic diagram of a third embodiment of the common-mode voltage and common-mode current suppressing circuit of the present application. The common mode voltage and common mode current suppressing circuit 20 includes an ac/dc power module 201, an ac side filter 203 having a first ac side filter capacitor 2C1, and a dc side support capacitor 2C2.

The ac side filter 203 is provided on the ac side of the ac/dc power module 201. The ac side filter 203 is in the form of an LC filter or an LCL filter, and in this example, the ac side filter 203 is in the form of an LCL filter, and further includes an inverter side inductor 2L1 and a distribution network side inductor 2L2, where the inverter side inductor 2L1 is close to the ac side of the ac/dc power module 201, and the first ac side filter capacitor 2C1 is disposed between the inverter side inductor 2L1 and the distribution network side inductor 2L 2.

The direct current side supporting capacitor 2C2 is disposed on the direct current side of the ac/dc power module 201, the direct current side common mode reflux capacitor 2C3 is disposed on the direct current side of the ac/dc power module 201, and the virtual neutral point of the first ac side filtering capacitor 2C1 is connected with the midpoint of the direct current side common mode reflux capacitor 2C3 to form a common mode current reflux path, so as to provide a common mode low pass filtering path inside the system for the common mode current.

Meanwhile, a dc side common mode inductance 2L3 is disposed on the dc side of the ac/dc power module 201 corresponding to the dc side common mode reflux capacitor 2C3, and the dc side common mode inductance 2L3 is disposed between the dc side supporting capacitor 2C2 and the dc side common mode reflux capacitor 2C 3.

The ac side of the ac/dc power module 201 is provided with a second ac side filter capacitor 2C4 opposite to the first ac side filter capacitor 2C1, and the second ac side filter capacitor 2C4 is disposed between the first ac side filter capacitor 2C1 and the inverter side inductor 2L 1.

The connection mode of the second ac side filter capacitor 2C4 may be a triangle connection as shown in fig. 3a, or the connection mode of the second ac side filter capacitor 2C4 may be changed to a star connection as shown in fig. 3 b. The two connection modes are different in that: to achieve the same filtering effect, the second ac side filter capacitor 2C4 of the star connection needs a larger capacitance.

The difference between the second embodiment and the third embodiment is only different in the connection mode of the second ac side filter capacitor 2C4, and other structures and functions are the same, and the parameters of the first ac side filter capacitor 2C1, the dc side common mode inductor 2L3 and the dc side common mode reflux capacitor 2C3 are selected appropriately, so that the common mode voltage of the ac side and the common mode voltage of the dc side are suppressed to be within the allowable range of the system, and the common mode current of the ac side to the ground and the common mode current of the dc side to the ground outside the system can be effectively reduced, thereby achieving the aim of suppressing the common mode voltage and the common mode current without isolating the transformer.

In addition, the difference between the second embodiment and the first embodiment is that the ac side of the ac/dc power module 201 is provided with the second ac side filter capacitor 2C4 opposite to the first ac side filter capacitor 2C1, so that the parameters of the first ac side filter capacitor 2C1 can be flexibly selected according to the system requirement to meet the requirement of common mode rejection, and the second ac side filter capacitor 2C4 can be independently selected according to the requirement of the current harmonic wave and the voltage harmonic wave of the ac side, thereby increasing the flexibility of the system.

Embodiment four:

referring to fig. 4 in combination, fig. 4 is a schematic diagram of a fourth embodiment of the common mode voltage and common mode current suppressing circuit of the present application. The common mode voltage and common mode current suppressing circuit 40 includes an ac/dc power module 401, an ac side filter 403 having a first ac side filter capacitor 4C1, and a dc side support capacitor 4C2.

The ac side filter 403 is provided on the ac side of the ac/dc power module 401. The ac side filter 403 is in the form of an LC filter or an LCL filter, in this example, the ac side filter 403 is in the form of an LCL filter, and further includes an inverter side inductor 4L1 and a distribution network side inductor 4L2, the inverter side inductor 4L1 is close to the ac side of the ac/dc power module 401, and the first ac side filter capacitor 4C1 is disposed between the inverter side inductor 4L1 and the distribution network side inductor 4L 2. In another embodiment, the ac side filter 403 is in the form of an LC filter, and the other matters are identical and will not be described herein.

The dc side supporting capacitor 4C2 is disposed on the dc side of the ac/dc power module 401, an ac side common mode inductor 4L4 is disposed between the ac side of the ac/dc power module 401 and the ac side filter 403, and a virtual neutral point of the first ac side filter capacitor 4C1 is connected with a midpoint of the dc side supporting capacitor 4C2, so as to form a common mode current return path, and provide a common mode low-pass filter path inside the system for the common mode current.

The difference between the embodiment and the first embodiment is that the ac/dc power module 401 includes the ac side common-mode inductor 4L4, and the common-mode voltage on the ac side and the common-mode voltage on the dc side can be suppressed to the allowable range of the system by selecting the appropriate parameters of the first ac side filter capacitor 4C1, the ac side common-mode inductor 4L4 and the dc side supporting capacitor 4C2, and the common-mode current on the ac side and the common-mode current on the dc side outside the system can be effectively reduced, so as to achieve the common-mode voltage and common-mode current suppression goal without an isolation transformer.

Fifth embodiment:

referring to fig. 5 in combination, fig. 5 is a schematic diagram of a fifth embodiment of the common mode voltage and common mode current suppressing circuit of the present application. The common mode voltage and common mode current suppressing circuit 50 includes an ac/dc power module 501, an ac side filter 503 having a first ac side filter capacitor 5C1, and a dc side support capacitor 5C2.

The ac side filter 503 is disposed on the ac side of the ac/dc power module 501. The ac side filter 503 is in the form of an LC filter or an LCL filter, in this example, the ac side filter 503 is in the form of an LCL filter, and further includes an inverter side inductor 5L1 and a distribution network side inductor 5L2, the inverter side inductor 5L1 is close to the ac side of the ac/dc power module 501, and the first ac side filter capacitor 5C1 is disposed between the inverter side inductor 5L1 and the distribution network side inductor 5L 2. In another embodiment, the ac side filter 503 is in the form of an LC filter, and the other matters are identical and will not be described herein.

The dc side supporting capacitor 5C2 is disposed on the dc side of the ac/dc power module 501, an ac side common mode inductor 5L4 is disposed between the ac side of the ac/dc power module 501 and the ac side filter 503, a dc side common mode return capacitor 5C3 is disposed on the dc side of the ac/dc power module 501, and a virtual neutral point of the first ac side filter capacitor 5C1 is connected with a midpoint of the dc side common mode return capacitor 5C3 to form a common mode current return path, so as to provide a common mode low-pass filter path inside the system for the common mode current.

The difference between the present embodiment and the fourth embodiment is that the dc side common-mode reflux capacitor 5C3 is disposed on the dc side of the ac/dc power module 501, and the common-mode voltage on the ac side and the common-mode voltage on the dc side can be suppressed to the allowable range of the system by selecting appropriate parameters of the first ac side filter capacitor 5C1, the ac side common-mode inductor 5L4 and the dc side common-mode reflux capacitor 5C3, and the common-mode voltage on the ac side and the common-mode voltage on the dc side can be effectively reduced, so that the common-mode voltage and the common-mode current on the dc side outside the system can be suppressed without isolating the transformer.

Example six:

referring to fig. 6 in combination, fig. 6 is a schematic diagram of a sixth embodiment of the common mode voltage and common mode current suppressing circuit of the present application. The common mode voltage and common mode current suppressing circuit 60 includes an ac/dc power module 601, an ac side filter 603 having a first ac side filter capacitor 6C1, and a dc side support capacitor 6C2.

The ac side filter 603 is disposed on the ac side of the ac/dc power module 601. The ac side filter 603 is in the form of an LC filter or an LCL filter, in this example, the ac side filter 603 is in the form of an LCL filter, and further includes an inverter side inductor 6L1 and a distribution network side inductor 6L2, the inverter side inductor 6L1 is close to the ac side of the ac/dc power module 601, and the first ac side filter capacitor 6C1 is disposed between the inverter side inductor 6L1 and the distribution network side inductor 6L 2. In another embodiment, the ac side filter 603 is in the form of an LC filter, and the other matters are identical and will not be described herein.

The dc side supporting capacitor 6C2 is disposed on the dc side of the ac/dc power module 601, an ac side common mode inductor 6L4 is disposed between the ac side of the ac/dc power module 601 and the ac side filter 603, and a virtual neutral point of the first ac side filter capacitor 6C1 is connected with a midpoint of the dc side supporting capacitor 6C2, so as to form a common mode current return path, and provide a common mode low-pass filter path inside the system for the common mode current.

The ac side of the ac/dc power module 601 is provided with a second ac side filter capacitor 6C4 opposite to the first ac side filter capacitor 6C1, and the second ac side filter capacitor 6C4 is disposed between the first ac side filter capacitor 6C1 and the inverter side inductor 6L 1.

The connection mode of the second ac side filter capacitor 6C4 may be a triangle connection mode or a star connection mode, and the triangle connection mode in this embodiment may be referred to as the star connection mode in embodiment three. The two connection modes are different in that: to achieve the same filtering effect, the second ac side filter capacitor 6C4 of the star connection needs a larger capacitance.

The difference between the present embodiment and the fourth embodiment is that the ac side common-mode inductor 6L4 is disposed on the ac side of the ac/dc power module 601, and the common-mode voltage on the ac side and the common-mode voltage on the dc side can be suppressed to the allowable range of the system by selecting appropriate parameters of the first ac side filter capacitor 6C1, the ac side common-mode inductor 6L4, and the dc side support capacitor 6C2, and the common-mode current on the ac side and the common-mode current on the dc side outside the system can be effectively reduced, so as to achieve the common-mode voltage and common-mode current suppression goal without an isolation transformer.

In addition, in the embodiment, the ac side of the ac/dc power module 601 is provided with the second ac side filter capacitor 6C4 opposite to the first ac side filter capacitor 6C1, so that parameters of the first ac side filter capacitor 6C1 can be flexibly selected according to the system requirement to meet the requirement of common mode rejection, and the second ac side filter capacitor 6C4 can be independently selected according to the requirements of current harmonic and voltage harmonic of the ac side, thereby increasing the flexibility of the system.

Embodiment seven:

referring to fig. 7 in combination, fig. 7 is a schematic diagram of a seventh embodiment of the common mode voltage and common mode current suppressing circuit of the present application. The common mode voltage and common mode current suppressing circuit 70 includes an ac/dc power module 701, an ac side filter 703 having a first ac side filter capacitor 7C1, and a dc side support capacitor 7C2.

The ac side filter 703 is provided on the ac side of the ac/dc power module 701. The ac side filter 703 is in the form of an LC filter or an LCL filter, and in this example, the ac side filter 703 is in the form of an LCL filter, and further includes an inverter side inductor 7L1 and a distribution network side inductor 7L2, where the inverter side inductor 7L1 is close to the ac side of the ac/dc power module 701, and the first ac side filter capacitor 7C1 is disposed between the inverter side inductor 7L1 and the distribution network side inductor 7L 2. In another embodiment, the ac side filter 703 is in the form of an LC filter, and the other matters are identical and will not be described herein.

The dc side supporting capacitor 7C2 is disposed on the dc side of the ac/dc power module 701, an ac side common mode inductor 7L4 is disposed between the ac side of the ac/dc power module 701 and the ac side filter 703, a dc side common mode return capacitor 7C3 is disposed on the dc side of the ac/dc power module 701, and a virtual neutral point of the first ac side filter capacitor 7C1 is connected with a midpoint of the dc side common mode return capacitor 7C3 to form a common mode current return path, so as to provide a common mode low-pass filter path inside the system for the common mode current.

The ac/dc power module 701 has a second ac side filter capacitor 7C4 opposite to the first ac side filter capacitor 7C1, and the second ac side filter capacitor 7C4 is disposed between the first ac side filter capacitor 7C1 and the inverter side inductor 7L 1.

The connection mode of the second ac side filter capacitor 7C4 may be a triangle connection mode or a star connection mode, and the triangle connection mode in this embodiment may be referred to as the star connection mode in embodiment three. The two connection modes are different in that: to achieve the same filtering effect, the second ac side filter capacitor 7C4 of the star connection needs a larger capacitance.

The difference between the present embodiment and the sixth embodiment is that the dc side common-mode reflux capacitor 7C3 is provided on the dc side of the ac/dc power module 701, and the common-mode voltage on the ac side and the common-mode voltage on the dc side can be suppressed to the allowable range of the system by selecting appropriate parameters of the first ac side filter capacitor 7C1, the ac side common-mode inductor 7L4, and the dc side common-mode reflux capacitor 7C3, and the common-mode voltage on the ac side and the common-mode voltage on the dc side can be effectively reduced, so that the common-mode voltage and the common-mode current on the dc side outside the system can be suppressed without isolating the transformer.

In addition, in the embodiment, the ac side of the ac/dc power module 701 is provided with the second ac side filter capacitor 7C4 opposite to the first ac side filter capacitor 7C1, so that parameters of the second ac side filter capacitor 7C4 can be flexibly selected according to the system requirement to meet the requirement of common mode rejection, and flexibility is increased; meanwhile, the direct current side common mode reflux capacitor 7C3 is arranged on the direct current side of the alternating current/direct current power module 701, so that parameters of the direct current side common mode reflux capacitor 7C3 can be flexibly selected according to the needs of a system to meet the requirement of common mode rejection, and the flexibility is increased.

Example eight:

referring to fig. 8 in combination, fig. 8 is a schematic diagram of an embodiment eight of the common mode voltage and common mode current suppressing circuit of the present application. The common mode voltage and common mode current suppressing circuit 80 includes an ac/dc power module 801, an ac side filter 803 having a first ac side filter capacitor 8C1, and a dc side support capacitor 8C2.

The ac side filter 803 is provided on the ac side of the ac/dc power module 801. The ac side filter 803 is in the form of an LC filter or an LCL filter, and in this example, the ac side filter 803 is in the form of an LCL filter, and further includes an inverter side inductor 8L1 and a distribution network side inductor 8L2, where the inverter side inductor 8L1 is close to the ac side of the ac/dc power module 801, and the first ac side filter capacitor 8C1 is disposed between the inverter side inductor 8L1 and the distribution network side inductor 8L 2. In another embodiment, the ac side filter 803 is in the form of an LC filter, and the other matters are identical and will not be described herein.

The dc side supporting capacitor 8C2 is disposed on the dc side of the ac/dc power module 801, an ac side common mode inductor 8L4 is disposed between the ac side of the ac/dc power module 801 and the ac side filter 803, a dc side common mode return capacitor 8C3 is disposed on the dc side of the ac/dc power module 801, and a virtual neutral point of the first ac side filter capacitor 8C1 is connected with a midpoint of the dc side common mode return capacitor 8C3 to form a common mode current return path, so as to provide a common mode low-pass filter path inside the system for the common mode current.

Meanwhile, a dc side common mode inductance 8L3 is disposed on the dc side of the ac/dc power module 801 corresponding to the dc side common mode reflux capacitor 8C3, and the dc side common mode inductance 8L3 is disposed between the dc side supporting capacitor 8C2 and the dc side common mode reflux capacitor 8C 3.

The ac side of the ac/dc power module 801 is provided with a second ac side filter capacitor 8C4 opposite to the first ac side filter capacitor 8C1, and the second ac side filter capacitor 8C4 is disposed between the first ac side filter capacitor 8C1 and the inverter side inductor 8L 1.

The connection mode of the second ac side filter capacitor 8C4 may be a triangle connection mode or a star connection mode, and the triangle connection mode in this embodiment may be referred to as the star connection mode in embodiment three. The two connection modes are different in that: to achieve the same filtering effect, the second ac side filter capacitor 8C4 of the star connection needs a larger capacitance.

The difference between the present embodiment and the seventh embodiment is that the dc side common-mode inductor 8L3 is disposed between the dc side supporting capacitor 8C2 and the dc side common-mode reflux capacitor 8C3, and the common-mode voltage on the ac side and the common-mode voltage on the dc side can be suppressed to the allowable range of the system by selecting appropriate parameters of the first ac side filter capacitor 8C1, the dc side common-mode inductor 8L3, the ac side common-mode inductor 8L4, and the dc side common-mode reflux capacitor 8C3, and the common-mode voltage on the ac side and the common-mode voltage on the dc side can be effectively reduced, so that the common-mode voltage and the common-mode current on the dc side outside the system can be suppressed without isolation transformers.

In addition, in this embodiment, since the ac side and the dc side of the ac/dc power module 801 are configured with common-mode inductors, the inductance of each common-mode inductor can be reduced accordingly, so that the size and weight of each common-mode inductor are reduced, and different systems can be adapted more conveniently.

Example nine:

referring to fig. 9 in combination, fig. 9 is a schematic diagram of a common mode voltage and common mode current suppressing circuit according to a ninth embodiment of the application. The common mode voltage and common mode current suppressing circuit 90 includes an ac/dc power module 901, an ac side filter 903 having a first ac side filter capacitor 9C1, and a dc side support capacitor 9C2.

The ac side filter 903 is provided on the ac side of the ac/dc power module 901. The ac side filter 903 is in the form of an LC filter or an LCL filter, and in this example, the ac side filter 903 is in the form of an LCL filter, and further includes an inverter side inductor 9L1 and a distribution network side inductor 9L2, where the inverter side inductor 9L1 is close to the ac side of the ac/dc power module 901, and the first ac side filter capacitor 9C1 is disposed between the inverter side inductor 9L1 and the distribution network side inductor 9L 2. In another embodiment, the ac side filter 903 is in the form of an LC filter, and the other matters are identical and will not be described herein.

The dc side supporting capacitor 9C2 is disposed on the dc side of the ac/dc power module 901, the dc side common mode reflux capacitor 9C3 is disposed on the dc side of the ac/dc power module 901, the virtual neutral point of the first ac side filtering capacitor 9C1 is connected with the midpoint of the dc side common mode reflux capacitor 9C3 to form a common mode current reflux path, a common mode low pass filtering path inside the system is provided for the common mode current, the ac side capacitor branch or the dc side capacitor branch of the ac/dc power module 901 is provided with the first series resistor 9R1 or both branches, and in this embodiment, the ac side capacitor branch and the dc side capacitor branch of the ac/dc power module 901 are preferably provided with the first series resistor 9R1.

Meanwhile, a dc side common mode inductance 9L3 is disposed on the dc side of the ac/dc power module 901 corresponding to the dc side common mode reflux capacitor 9C3, and the dc side common mode inductance 9L3 is disposed between the dc side supporting capacitor 9C2 and the dc side common mode reflux capacitor 9C 3.

The embodiment is modified on the basis of the first embodiment, and the main difference is that the first series resistor 9R1 is simultaneously disposed in the ac side capacitor branch and the dc side capacitor branch of the ac/dc power module 901, so as to reduce the instantaneous common mode current spike when the system is started.

Of course, in any of the first to eighth embodiments, as in the present embodiment, the first series resistor 9R1 may be simultaneously disposed in the ac-side capacitor branch or the dc-side capacitor branch of the ac/dc power module 901 or in both branches, and the description thereof will be omitted. In this embodiment, by selecting a suitable resistance value of the first series resistor 9R1, an instantaneous common mode current spike during system start-up can be effectively suppressed.

Example ten:

referring to fig. 10 in combination, fig. 10 is a schematic diagram of a common mode voltage and common mode current suppressing circuit according to an embodiment of the present application. The common mode voltage and common mode current suppressing circuit 100 includes an ac/dc power module 1001, an ac side filter 1003 having a first ac side filter capacitor 10C1, and a dc side support capacitor 10C2.

The ac side filter 1003 is provided on the ac side of the ac/dc power module 1001. The ac side filter 1003 is in the form of an LC filter or an LCL filter, in this example, the ac side filter 1003 is in the form of an LCL filter, and further includes an inverter side inductor 10L1 and a distribution network side inductor 10L2, the inverter side inductor 10L1 is close to the ac side of the ac/dc power module 1001, and the first ac side filter capacitor 10C1 is disposed between the inverter side inductor 10L1 and the distribution network side inductor 10L 2. In another embodiment, the ac side filter 1003 is in the form of an LC filter, and the other matters are identical and will not be described herein.

The dc side supporting capacitor 10C2 is disposed on the dc side of the ac/dc power module 1001, the dc side common mode reflux capacitor 10C3 is disposed on the dc side of the ac/dc power module 1001, the virtual neutral point of the first ac side filtering capacitor 10C1 is connected with the midpoint of the dc side common mode reflux capacitor 10C3, a common mode current reflux path is formed, a common mode low pass filtering path inside the system is provided for the common mode current, a second series resistor 10R2 is disposed on the common mode current reflux path, and the second series resistor 10R2 is disposed between the virtual neutral point of the first ac side filtering capacitor 10C1 and the midpoint of the dc side common mode reflux capacitor 10C 3.

The present embodiment is modified based on the first embodiment, and the main difference is that the second series resistor 10R2 is disposed between the virtual neutral point of the first ac side filter capacitor 10C1 and the midpoint of the dc side common mode reflux capacitor 10C3, so as to reduce the instantaneous common mode current peak when the system is started.

Of course, in any of the first to eighth embodiments, as in the present embodiment, the second series resistor 10R2 is disposed between the virtual neutral point of the first ac side filter capacitor 10C1 and the midpoint of the dc side common mode feedback capacitor 10C3, and will not be described herein. In this embodiment, by selecting a suitable resistance value of the second series resistor 10R2, an instantaneous common mode current spike during system start-up can be effectively suppressed.

Example eleven:

referring to fig. 11 in combination, fig. 11 is a schematic diagram of an embodiment of a common mode voltage and common mode current suppressing circuit according to the present application. The common mode voltage and common mode current suppressing circuit 110 includes an ac/dc power module 1101, an ac side filter 1103 having a first ac side filter capacitor 11C1, and a dc side support capacitor 11C2.

The ac side filter 1103 is provided on the ac side of the ac/dc power module 1101. The ac side filter 1103 is in the form of an LC filter or an LCL filter, and in this example, the ac side filter 1103 is in the form of an LCL filter, and further includes an inverter side inductor 11L1 and a distribution network side inductor 11L2, where the inverter side inductor 11L1 is close to the ac side of the ac/dc power module 1101, and the first ac side filter capacitor 11C1 is disposed between the inverter side inductor 11L1 and the distribution network side inductor 11L 2. In another embodiment, the ac side filter 1103 is in the form of an LC filter, and the other matters are identical and will not be described herein.

The direct current side supporting capacitor 11C2 is disposed on a direct current side of the ac/dc power module 1101, a direct current side common mode reflux capacitor 11C3 is disposed on the direct current side of the ac/dc power module 1101, a third alternating current side filter capacitor 11C5 is disposed on the alternating current side of the ac/dc power module 1101 opposite to the first alternating current side filter capacitor 11C1 and the second alternating current side filter capacitor 11C4, a virtual neutral point of the first alternating current side filter capacitor 11C1 and a virtual neutral point of the third alternating current side filter capacitor 11C5 are connected with a midpoint of the direct current side common mode reflux capacitor 11C3, and a second-stage common mode low-pass filter path is provided for common mode current.

Meanwhile, a dc side common mode inductor 11L3 is disposed on the dc side of the ac/dc power module 1101 corresponding to the dc side common mode reflux capacitor 11C3, and the dc side common mode inductor 11L3 is disposed between the dc side supporting capacitor 11C2 and the dc side common mode reflux capacitor 11C 3.

The ac side of the ac/dc power module 1101 is provided with a second ac side filter capacitor 11C4 opposite to the first ac side filter capacitor 11C1, and the second ac side filter capacitor 11C4 is disposed between the first ac side filter capacitor 11C1 and the inverter side inductor 11L 1.

The connection mode of the second ac side filter capacitor 11C4 may be a triangle connection mode or a star connection mode, and the triangle connection mode in this embodiment may be referred to as the star connection mode in embodiment three. The two connection modes are different in that: in order to achieve the same filtering effect, the second ac side filter capacitor 11C4 of the star connection needs to have a larger capacitance.

The main difference of this embodiment is that the ac/dc power module 1101 includes a third ac side filter capacitor 11C5 opposite to the first ac side filter capacitor 11C1 and the second ac side filter capacitor 11C4, and the virtual neutral point of the first ac side filter capacitor 11C1 and the virtual neutral point of the third ac side filter capacitor 11C5 are connected to the midpoint of the dc side common mode return capacitor 11C3, so as to provide a second common mode low pass filter path for the common mode current. In the method, by selecting the parameters of the first ac side filter capacitor 11C1, the dc side common mode inductor 11L3, the dc side common mode reflux capacitor 11C3, and the third ac side filter capacitor 11C5, the common mode voltage on the ac side and the common mode voltage on the dc side can be suppressed to the allowable range of the system, and the common mode current on the ac side and the common mode current on the dc side outside the system can be effectively reduced, so that the common mode voltage and the common mode current suppression target without isolating the transformer can be achieved.

Of course, in any of the first to tenth embodiments, as in the present embodiment, a third ac side filter capacitor 11C5 may be disposed on the ac side of the ac/dc power module 1101 opposite to the first ac side filter capacitor 11C1 and the second ac side filter capacitor 11C4, and a virtual neutral point of the first ac side filter capacitor 11C1 and a virtual neutral point of the third ac side filter capacitor 11C5 may be connected to a midpoint of the dc side common mode return capacitor 11C3 to provide a second common mode low pass filter path for the common mode current.

Embodiment twelve:

referring to fig. 12, fig. 12 is a schematic diagram of a twelfth embodiment of the common mode voltage and common mode current suppressing circuit of the present application, which is basically identical to fig. 11, except that the inverter side inductor 11L1 and the dc side common mode inductor 11L3 are magnetically integrated, so that the inverter side inductor 11L1 and the dc side common mode inductor 11L3 share a magnetic core, thereby reducing cost and volume.

Of course, in the above embodiments, as long as the inverter side inductor 11L1 and the dc side common mode inductor 11L3 are provided, the inverter side inductor 11L1 and the dc side common mode inductor 11L3 may be magnetically integrated with reference to embodiment twelve, and the description thereof will be omitted.

Embodiment thirteen:

referring to fig. 13, fig. 13 is a schematic diagram of a thirteenth embodiment of the common mode voltage and common mode current suppressing circuit of the present application, which is basically identical to fig. 7, except that the inverter side inductor 7L1 and the ac side common mode inductor 7L4 are magnetically integrated, so that the inverter side inductor 7L1 and the ac side common mode inductor 7L4 share a magnetic core, thereby reducing cost and volume.

Of course, in each of the above embodiments, as long as the inverter side inductor 7L1 and the ac side common mode inductor 7L4 are provided, reference may be made to the thirteenth embodiment, and the inverter side inductor 7L1 and the ac side common mode inductor 7L4 may be magnetically integrated, and the description thereof will be omitted.

Fourteen examples:

referring to fig. 11, the present embodiment is substantially identical to the eleventh embodiment shown in fig. 11, and is different in that the inverter side inductor 11L1 and the distribution network side inductor 11L2 are magnetically integrated, so that the inverter side inductor 11L1 and the distribution network side inductor 11L2 share a magnetic core, thereby reducing cost and volume.

Of course, in the above embodiments, as long as the inverter side inductor 11L1 and the distribution network side inductor 11L2 are provided, reference may be made to embodiment eleven, and the inverter side inductor 11L1 and the distribution network side inductor 11L2 may be magnetically integrated, which is not described herein.

Compared with the prior art, the common-mode voltage and common-mode current suppression circuit provided by the utility model has the advantages that the virtual neutral point of the first alternating-current side filter capacitor is connected with the middle point of the direct-current side common-mode reflux capacitor by introducing the direct-current side common-mode reflux capacitor into the direct-current side, or the virtual neutral point of the first alternating-current side filter capacitor is connected with the middle point of the direct-current side support capacitor into the alternating-current side common-mode inductor, so that a common-mode current reflux path is formed, and a common-mode low-pass filter path in a system is provided for common-mode current, so that common-mode voltage and common-mode current are suppressed. The utility model not only omits an isolation transformer, reduces the cost, reduces the volume and improves the efficiency, but also effectively inhibits the common-mode voltage and the common-mode current of the alternating current side and the direct current side.

In addition, the direct-current side common-mode reflux capacitor and the alternating-current side common-mode inductance parameter can be adjusted, and the direct-current side common-mode reflux capacitor and the alternating-current side common-mode inductance parameter can be widely applied to energy storage systems with various power grades and various voltage grades, battery formation systems, photovoltaic power generation systems, micro-grids, motor transmission and other application scenes, and are wide in applicability. While the utility model has been described with respect to the above embodiments, it should be noted that modifications can be made by those skilled in the art without departing from the inventive concept, and these are all within the scope of the utility model.

Claims (9)

1. A common mode voltage and common mode current rejection circuit comprising:

an ac/dc power module;

an ac side filter having a first ac side filter capacitor, disposed on an ac side of the ac/dc power module; a kind of electronic device with high-pressure air-conditioning system

The direct current side supporting capacitor is arranged on the direct current side of the alternating current/direct current power module, and is characterized in that a direct current side common mode reflux capacitor is arranged on the direct current side of the alternating current/direct current power module, a virtual neutral point of the first alternating current side filtering capacitor is connected with a midpoint of the direct current side common mode reflux capacitor, or an alternating current side common mode inductor is arranged between the alternating current side of the alternating current/direct current power module and the alternating current side filter, and the virtual neutral point of the first alternating current side filtering capacitor is connected with the midpoint of the direct current side supporting capacitor to form a common mode current reflux path so as to provide a common mode low-pass filtering path in a system for common mode current.

2. The common-mode voltage and common-mode current suppressing circuit according to claim 1, wherein the ac side filter is in the form of an LC filter or an LCL filter, the LC filter includes an inverter side inductor and the first ac side filter capacitor, the LCL filter is provided with a distribution network side inductor on the basis of the LC filter, the inverter side inductor is close to the ac side of the ac/dc power module, and the first ac side filter capacitor is provided between the inverter side inductor and the distribution network side inductor.

3. The common mode voltage and common mode current suppressing circuit according to claim 1, wherein the ac/dc power module dc side is provided with a dc side common mode inductance with respect to the dc side common mode return capacitance, the dc side common mode inductance being provided between the dc side support capacitance and the dc side common mode return capacitance.

4. The common-mode voltage and common-mode current suppressing circuit according to claim 2, wherein the ac side of the ac/dc power module is provided with a second ac side filter capacitor opposite to the first ac side filter capacitor, the second ac side filter capacitor is disposed between the first ac side filter capacitor and the inverter side inductor, and the connection manner of the second ac side filter capacitor is a delta connection or a star connection.

5. The common-mode voltage and current suppressing circuit according to claim 4, wherein the ac/dc power module ac side is provided with a third ac side filter capacitor with respect to the first ac side filter capacitor and the second ac side filter capacitor, and a virtual neutral point of the first ac side filter capacitor and a virtual neutral point of the third ac side filter capacitor are connected to a midpoint of the dc side common-mode return capacitor to provide a second-stage common-mode low-pass filter path for the common-mode current.

6. The common mode voltage and common mode current suppressing circuit according to claim 1, wherein the ac/dc power module ac side is provided with the ac side common mode inductance while the dc side common mode return capacitance is provided on the ac/dc power module dc side.

7. The common mode voltage and common mode current suppressing circuit according to claim 1, wherein a first series resistance is provided in an ac side capacitor branch or a dc side capacitor branch of the ac/dc power module.

8. The common mode voltage and common mode current suppressing circuit according to claim 1, wherein a second series resistor is provided on the common mode current return path.

9. A common mode voltage and current suppressing circuit according to any one of claims 1 to 8, wherein magnetic integration is performed between two inductors disposed adjacently.