阅读说明：本技术 一种变流器的共模电流抑制方法、装置以及变流器 (Common-mode current suppression method and device of converter and converter ) 是由 杨北辉 朱和祥 吴能峰 于 2021-09-10 设计创作，主要内容包括：本申请公开了一种变流器的共模电流抑制方法,包括：将变流器的功率单元与地绝缘；将所述功率单元与所述变流器的箱体外壳通过导线相连,形成包含所述功率单元与所述箱体外壳、用于消耗共模电流的回流通路；在所述功率单元与所述箱体外壳之间设置滤波电路。应用该方法能够高效的抑制共模电流,降低对轨旁设备的干扰。本申请还公开了一种变流器的共模电流抑制装置以及变流器,均具有上述技术效果。(The application discloses a common-mode current suppression method of a converter, which comprises the following steps: insulating a power unit of the converter from the ground; connecting the power unit with a box body shell of the converter through a lead to form a return circuit which comprises the power unit and the box body shell and is used for consuming common-mode current; and a filter circuit is arranged between the power unit and the box body shell. By the method, common-mode current can be effectively inhibited, and interference on trackside equipment is reduced. The application also discloses a common mode current suppression device of the converter and the converter, and the common mode current suppression device and the converter both have the technical effects.)

1. A common mode current suppression method of a current transformer is characterized by comprising the following steps:

insulating a power unit of the converter from the ground;

connecting the power unit with a box body shell of the converter through a lead to form a return circuit which comprises the power unit and the box body shell and is used for consuming common-mode current;

and a filter circuit is arranged between the power unit and the box body shell.

2. A common-mode current suppression method according to claim 1, wherein the disposing a filter circuit between the power unit and the case housing comprises:

the filter circuit is arranged between the radiator substrate of the power unit and the box body shell.

3. A common-mode current suppression method according to claim 1, characterized in that the filter circuit comprises a notch filter.

4. The common-mode current suppression method according to claim 1, further comprising:

acquiring a frequency band of trackside equipment;

and adjusting circuit parameters of the filter circuit according to the acquired frequency band so as to change the peak value of the common-mode current.

5. A common mode current suppression device for a current transformer, comprising:

the first setting module is used for insulating a power unit of the converter from the ground;

the connecting module is used for connecting the power unit with a box body shell of the converter through a lead to form a return circuit which comprises the power unit and the box body shell and is used for consuming common-mode current;

and the second setting module is used for setting a filter circuit between the power unit and the box body shell.

6. A common-mode current suppression device according to claim 5, characterized in that the second setting module is specifically configured to set the filter circuit between a heat sink substrate of the power unit and the case housing.

7. A common-mode current suppression device according to claim 5, further comprising:

the acquisition module is used for acquiring a frequency band of the trackside equipment;

and the adjusting module is used for adjusting the circuit parameters of the filter circuit according to the acquired frequency band so as to change the peak value of the common-mode current.

8. A current transformer is characterized in that a power unit of the current transformer is insulated from the ground; the power unit is connected with a box body shell of the converter through a lead to form a backflow passage which comprises the power unit and the box body shell and is used for consuming common-mode current; and a filter circuit is arranged between the power unit and the box body shell.

9. The converter according to claim 8, wherein said filter circuit comprises a notch filter.

10. The converter according to claim 8, wherein the filter circuit is located between a heat sink base plate of the power cell and the case housing.

Technical Field

The application relates to the technical field of converters, in particular to a common-mode current suppression method of a converter; the common-mode current suppression device of the current transformer and the current transformer are further related.

Background

The converter can invert the direct current into three-phase alternating current with adjustable voltage and frequency, and the three-phase alternating current is used for driving the traction motor. The fundamental phase angles of the voltages output by the output terminals U, V, W of the current transformer differ from each other by 120 °, and in the PWM control mode, the instantaneous value of the sum of the three-phase outputs is not zero, and a common mode voltage will exist. The power switching device of the converter is usually an IGBT switch, and in the PWM control mode, the IGBT switch generates a high dv/dt, that is, a high voltage change rate. The common-mode voltage and the higher voltage change rate act on the parasitic capacitance of the converter, so that not only can charge and discharge current be generated, but also the voltage of a power unit of the converter is increased due to the accumulation effect of the parasitic capacitance, and the common-mode current is generated. Common mode currents can couple to the body ground or negative line and interfere with trackside equipment, thus requiring common mode current rejection.

Currently, schemes for suppressing common mode current include: scheme 1, PWM modulation is eliminated through specific harmonic waves, and common mode current of a current transformer is reduced. Scheme 2, EMC capacitance is added in the converter, and a common-mode current return path is provided. However, in case of the scheme 1, since the switching frequency of the inverter in the train is low (500Hz or less), the effect of the scheme 1 on higher harmonics is limited, and the suppression effect of the common mode current is not good. For the scheme 2, due to the fact that a train loop is complex, the EMC capacitor needs to be selected by referring to empirical data, and system matching is complex; in addition, the capacitance value of the capacitor is easy to change after long-term use, which may cause the system to be unmatched, so that the common mode current cannot be effectively suppressed.

In view of the above, how to efficiently suppress the common mode current has become an urgent technical problem to be solved by those skilled in the art.

Disclosure of Invention

The common-mode current suppression method of the converter can effectively suppress the common-mode current and reduce interference on trackside equipment. Another object of the present application is to provide a common mode current suppression device for a converter and a converter, both having the above technical effects.

In order to solve the above technical problem, the present application provides a common mode current suppression method for a converter, including:

insulating a power unit of the converter from the ground;

connecting the power unit with a box body shell of the converter through a lead to form a return circuit which comprises the power unit and the box body shell and is used for consuming common-mode current;

and a filter circuit is arranged between the power unit and the box body shell.

Optionally, the step of arranging a filter circuit between the power unit and the box casing includes:

the filter circuit is arranged between the radiator substrate of the power unit and the box body shell.

Optionally, the filter circuit comprises a notch filter.

Optionally, the method further includes:

acquiring a frequency band of trackside equipment;

and adjusting circuit parameters of the filter circuit according to the acquired frequency band so as to change the peak value of the common-mode current.

In order to solve the above technical problem, the present application further provides a common mode current suppression device for a converter, including:

the first setting module is used for insulating a power unit of the converter from the ground;

the connecting module is used for connecting the power unit with a box body shell of the converter through a lead to form a return circuit which comprises the power unit and the box body shell and is used for consuming common-mode current;

and the second setting module is used for setting a filter circuit between the power unit and the box body shell.

Optionally, the second setting module is specifically configured to set the filter circuit between the heat sink substrate of the power unit and the box housing.

Optionally, the method further includes:

the acquisition module is used for acquiring a frequency band of the trackside equipment;

and the adjusting module is used for adjusting the circuit parameters of the filter circuit according to the acquired frequency band so as to change the peak value of the common-mode current.

In order to solve the technical problem, the application also provides a current transformer, wherein a power unit of the current transformer is insulated from the ground; the power unit is connected with a box body shell of the converter through a lead to form a backflow passage which comprises the power unit and the box body and is used for consuming common-mode current; and a filter circuit is arranged between the power unit and the box body shell.

Optionally, the filter circuit comprises a notch filter.

Optionally, the filter circuit is located between the heat sink substrate of the power unit and the case housing.

The common-mode current suppression method of the current transformer comprises the following steps: insulating a power unit of the converter from the ground; connecting the power unit with a box body shell of the converter through a lead to form a return circuit which comprises the power unit and the box body shell and is used for consuming common-mode current; and a filter circuit is arranged between the power unit and the box body shell.

Therefore, the common-mode current suppression method of the converter insulates the power unit of the converter from the ground, cuts off a path that the common-mode current flows into the ground terminal, and fundamentally suppresses the conduction of the common-mode current to the negative line wheel rail. The power unit is connected with a box body shell of the converter through a lead to form a return flow path comprising the power unit and the box body, so that common-mode current is consumed in the return flow path. In addition, by providing the filter circuit between the power unit and the case, the common mode current generated by the power unit can be more circulated and consumed in the return path including the power unit and the case. The more the common mode current in the return path, the less the interference to external conduction is, thereby effectively reducing the interference to the trackside equipment.

The common-mode current suppression device of the current transformer and the current transformer have the technical effects.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the prior art and the embodiments are briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic flowchart of a common mode current suppression method of a converter according to an embodiment of the present disclosure;

fig. 2 is a schematic diagram of a current transformer according to an embodiment of the present disclosure;

fig. 3 is a schematic diagram of a common mode current suppression device of a current transformer according to an embodiment of the present disclosure.

Detailed Description

The core of the application is to provide a common-mode current suppression method of a converter, which can efficiently suppress common-mode current and reduce interference on trackside equipment. The other core of the present application is to provide a common mode current suppression device of a current transformer and the current transformer, both having the above technical effects.

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, fig. 1 is a schematic flow chart of a method for suppressing a common mode current of a converter according to an embodiment of the present disclosure, referring to fig. 1, the method includes:

s101: insulating a power unit of the converter from the ground;

specifically, the step of insulating the power unit (mainly including the support capacitor, the laminated busbar and the radiator) of the converter from the ground means that the power unit of the converter is disconnected from the ground, that is, the power unit of the converter is not grounded. The power unit of the converter can be regarded as an interference source, and common-mode current generated by the power unit can be conducted to the wheel rail to interfere with trackside equipment. By insulating the power unit of the converter from the ground, the common-mode current generated by the power unit can be fundamentally inhibited from being led into the wheel rail, so that the interference on equipment beside the rail is reduced. The trackside equipment refers to equipment provided near the wheel track of the train.

S102: connecting the power unit with a box body shell of the converter through a lead to form a return circuit which comprises the power unit and the box body shell and is used for consuming common-mode current;

specifically, the step is to perform insulation treatment on the power unit and the case casing of the converter, connect the power unit and the case casing only through a lead, form a return path including the power unit and the case casing, and circulate and consume the common mode current in the return path. In addition, the box casing is connected with a grounding system through a lead.

The return passage comprises a power unit, a box body shell, a motor three-phase line, a motor shell and the like.

S103: and a filter circuit is arranged between the power unit and the box body shell.

Specifically, in this step, the power unit is connected to a case casing of the converter through a wire, so as to form a return path including the power unit and the case casing, and a filter circuit is further disposed on the return path, specifically, a filter circuit is disposed between the power unit and the case casing. Under the action of the filter circuit, the common mode current is easier to circulate and consume in the return circuit more. Under the condition of a certain total amount of interference sources, the more common-mode current in the return flow path, the less the naturally conducted common-mode current and the less external interference, so that the interference on the trackside equipment is reduced.

In a specific embodiment, the disposing a filter circuit between the power unit and the case housing includes: the filter circuit is arranged between the radiator substrate of the power unit and the box body shell.

Specifically, in the present embodiment, a filter circuit is provided between the heat sink substrate of the power unit and the case housing of the converter. At this time, the return path includes a power unit, a heat sink substrate, a filter circuit, a case, a three-phase motor line, a motor case, and the like.

Additionally, in a particular embodiment, the filtering circuit includes a notch filter.

Specifically, in the present embodiment, the filter circuit specifically includes a notch filter, and the notch filter may be specifically disposed between the heat sink substrate and the case housing of the converter.

For example, referring to fig. 2, Ces in fig. 2 represents a parasitic capacitance of the power device and the laminated busbar in the power unit to the heat sink substrate, and Csf represents a parasitic capacitance between the three phase lines of the motor and the motor housing. Reference numeral 10 denotes a power unit, reference numeral 20 denotes a radiator base plate, reference numeral 30 denotes a notch filter, reference numeral 40 denotes a case of a converter and a train body, reference numeral 50 denotes a motor case, and reference numeral 60 denotes a motor three-phase line.

The power device, the laminated busbar, the parasitic capacitor Ces, the notch filter, the box body casing, the motor casing, the parasitic capacitor Csf and the three phase lines of the motor form a complete backflow path (the backflow path indicated by an arrow in fig. 2), and the common mode current circulates and is consumed in the backflow path.

It is to be understood that the embodiment in which the filter circuit includes a notch filter is merely one implementation provided herein, and is not intended to be limiting, and that other filters may be used.

Further, on the basis of the above embodiment, as a specific implementation manner, the method may further include: acquiring a frequency band of trackside equipment; and adjusting circuit parameters of the filter circuit according to the acquired frequency band so as to change the peak value of the common-mode current.

Specifically, by adjusting circuit parameters of the filter circuit, the peak value of the common-mode current of different frequency bands in the return flow path can be changed, so that the interference on the trackside equipment is reduced.

For example, a subway train is generally provided with axle counting equipment beside a rail, the frequency section of the axle counting equipment which is easily interfered is certain, and the conducted interference peak value only needs to be smaller than the frequency section of the interfered axle counting equipment, so that the conducted interference peak value can be changed by adjusting the circuit parameters of the filter circuit, the conducted interference peak value is smaller than the frequency section of the interfered axle counting equipment, and the interference on the axle counting equipment is reduced.

For the case that the filter circuit comprises the notch filter, the conducted interference peak value can be changed by adjusting the parameters of the notch filter, and the interference to the trackside equipment is reduced, so that the method for suppressing the common-mode current has better universality.

In summary, the common-mode current suppression method for the current transformer provided by the present application includes: insulating a power unit of the converter from the ground; connecting the power unit with a box body shell of the converter through a lead to form a return circuit which comprises the power unit and the box body shell and is used for consuming common-mode current; and a filter circuit is arranged between the power unit and the box body shell. Therefore, the common-mode current suppression method of the converter insulates the power unit of the converter from the ground, cuts off a path that the common-mode current flows into the ground terminal, and fundamentally suppresses the conduction of the common-mode current to the negative line wheel rail. The power unit is connected with a box body shell of the converter through a lead to form a return flow path comprising the power unit and the box body shell, so that common-mode current is consumed in the return flow path. In addition, by providing the filter circuit between the power unit and the case, the common mode current generated by the power unit can be more circulated and consumed in the return path including the power unit and the case. The more the common mode current in the return path, the less the interference to external conduction is, thereby effectively reducing the interference to the trackside equipment.

The present application also provides a common mode current suppression device for a converter, which is described below and referred to above. Referring to fig. 3, fig. 3 is a schematic diagram of a common mode current suppression device of a current transformer according to an embodiment of the present application, and referring to fig. 3, the device includes:

the first setting module 1 is used for insulating a power unit of the converter from the ground;

the connecting module 2 is used for connecting the power unit with a box body shell of the converter through a lead to form a return circuit which comprises the power unit and the box body shell and is used for consuming common-mode current;

and the second setting module 3 is used for setting a filter circuit between the power unit and the box body shell.

Specifically, the first installation module 1 isolates the power unit of the converter from the ground, that is, the first installation module 1 disconnects the power unit of the converter from the ground, that is, the power unit of the converter is not grounded. The power unit can be regarded as an interference source, and the common-mode current generated by the power unit can be conducted to the wheel rail to interfere with trackside equipment. By insulating the power unit of the converter from the ground, the common-mode current generated by the power unit can be fundamentally inhibited from being led into the wheel rail, and the interference on equipment beside the rail is further reduced.

The connecting module 2 is used for insulating the box body shells of the power unit and the converter, and the power unit and the box body shells are connected only through a lead to form a return flow path comprising the power unit and the box body shells, so that common-mode current is circulated and consumed in the return flow path.

The return passage comprises a power unit, a box body shell, a motor three-phase line, a motor shell and the like.

On the basis that the connecting module 2 connects the power unit and the box body shell of the converter through a lead to form a return passage containing the power unit and the box body shell, the second setting module 3 is further provided with a filter circuit on the return passage, and particularly the second setting module 3 is provided with the filter circuit between the power unit and the box body shell. Under the action of the filter circuit, the common mode current is easier to circulate and consume in the return circuit more. Under the condition of a certain total amount of interference sources, the more common-mode current in the return flow path, the less common-mode current naturally conducted to the outside, and the less interference to the outside, so that the interference to trackside equipment is reduced.

On the basis of the foregoing embodiment, optionally, the second setting module 3 is specifically configured to set the filter circuit between the heat sink substrate of the power unit and the box casing.

Specifically, in the present embodiment, the second installation module 3 specifically installs a filter circuit between the heat sink substrate of the power unit and the case housing of the converter. At this time, the return path includes a power unit, a heat sink substrate, a filter circuit, a case housing, a three-phase motor line, a motor housing, and the like. The common mode current circulates and is consumed in a return circuit comprising a power unit, a radiator substrate, a filter circuit, a box body shell and a motor.

On the basis of the above embodiment, optionally, the filter circuit includes a notch filter.

Specifically, the filter circuit specifically includes a notch filter, and the notch filter may be specifically disposed between the heat sink substrate and the converter case housing, where the return path includes the power unit, the heat sink substrate, the notch filter, the case housing, the three-phase motor line, the motor housing, and the like.

On the basis of the above embodiment, optionally, the method further includes:

the acquisition module is used for acquiring a frequency band of the trackside equipment;

and the adjusting module is used for adjusting the circuit parameters of the filter circuit according to the acquired frequency band so as to change the peak value of the common-mode current.

Specifically, the frequency band of the trackside equipment is obtained through the obtaining module, and the circuit parameters of the filter circuit are adjusted through the adjusting module according to the obtained frequency band, so that the peak value of common-mode current of different frequency bands in the return flow path can be changed, and the interference on the trackside equipment is reduced.

For example, a subway train is generally provided with axle counting equipment beside a rail, the frequency section of the axle counting equipment which is easily interfered is certain, and the conducted interference peak value only needs to be smaller than the frequency section of the interfered axle counting equipment, so that the conducted interference peak value can be changed by adjusting the circuit parameters of the filter circuit, the conducted interference peak value is smaller than the frequency section of the interfered axle counting equipment, and the interference on the axle counting equipment is reduced.

According to the common-mode current suppression device of the current transformer, the power unit of the current transformer is insulated from the ground, a path that common-mode current flows into a grounding end is cut off, and the common-mode current is fundamentally suppressed from being conducted to a negative line wheel rail. The power unit is connected with the box body of the converter through a lead to form a return path comprising the power unit and the box body, so that the common mode current is consumed in the return path. In addition, by providing the filter circuit between the power unit and the case, the common mode current generated by the power unit can be more circulated and consumed in the return path including the power unit and the case. The more the common mode current in the return path, the less the interference to external conduction is, thereby effectively reducing the interference to the trackside equipment.

The application also provides a current transformer, wherein a power unit of the current transformer is insulated from the ground; the power unit is connected with a box body shell of the converter through a lead to form a backflow passage which comprises the power unit and the box body shell and is used for consuming common-mode current; and a filter circuit is arranged between the power unit and the box body shell.

Specifically, in the present application, the power unit of the converter is designed to be insulated from the ground. The power unit mainly comprises a support capacitor, a laminated busbar and a radiator. For the specific composition of the power unit, detailed description is not repeated herein, and reference may be made to the existing power unit.

The power unit of the converter is insulated from the ground, namely the power unit of the converter is disconnected from the ground, namely the power unit of the converter is not grounded. The power cell may be considered a source of interference that generates common mode currents that are conducted to the wheel track and interfere with trackside equipment. By designing the power unit of the converter to be insulated from the ground, the common-mode current generated by the power unit can be fundamentally inhibited from being led into the wheel rail, and the interference on equipment beside the rail is further reduced.

In the present application, the power cells of the converter and the case of the converter are connected only by wires, and a return path including the power cells and the case casing is formed so that the common mode current is circulated and consumed in the return path.

The return passage comprises a three-phase line of the motor, a motor shell and the like besides the power unit and the box body shell.

In addition, on the basis that the power unit is connected with a box body shell of the converter through a lead to form a return flow path comprising the power unit and the box body shell, a filter circuit is further arranged on the return flow path, and particularly the filter circuit is arranged between the power unit and the box body shell. Under the action of the filter circuit, the common mode current is easier to circulate and consume in the return circuit more. Under the condition of a certain total amount of interference sources, the more common-mode current in the return flow path, the less common-mode current naturally conducted to the outside, and the less interference to the outside, so that the interference to trackside equipment is reduced.

Furthermore, on the basis that a filter circuit is arranged between the power unit and the box body shell of the converter, the peak value of common-mode current of different frequency bands in a return flow path can be changed by adjusting the circuit parameters of the filter circuit, and the interference on trackside equipment is reduced.

For example, a subway train is generally provided with axle counting equipment beside a rail, the frequency section of the axle counting equipment which is easily interfered is certain, and the conducted interference peak value only needs to be smaller than the frequency section of the interfered axle counting equipment, so that the conducted interference peak value can be changed by adjusting the circuit parameters of the filter circuit, the conducted interference peak value is smaller than the frequency section of the interfered axle counting equipment, and the interference on the axle counting equipment is reduced.

On the basis of the above embodiment, optionally, the filter circuit includes a notch filter.

Specifically, in this embodiment, the filter circuit specifically includes a notch filter, and the notch filter may be specifically disposed between the heat sink substrate and the converter case housing, where the return path includes the power unit, the heat sink substrate, the notch filter, the case housing, the motor housing, and the like.

On the basis of the above embodiment, optionally, the filter circuit is located between the heat sink substrate of the power unit and the box casing.

Specifically, in this embodiment, the filter circuit is specifically disposed between the heat sink substrate of the power unit and the case housing of the converter. In this case, the return path includes a power unit, a heat sink substrate, a filter circuit, a case housing, a motor, and the like. The common mode current circulates and is consumed in a return circuit comprising a power unit, a radiator substrate, a filter circuit, a box body shell and a motor shell.

The power unit of the converter is insulated from the ground, the passage of common-mode current flowing into the grounding end is cut off, and the common-mode current is fundamentally inhibited from being conducted to the negative line wheel rail. The power unit is connected with a box body shell of the converter through a lead to form a return flow path comprising the power unit and the box body shell, so that common-mode current is consumed in the return flow path. In addition, by providing the filter circuit between the power unit and the case, the common mode current generated by the power unit can be more circulated and consumed in the return path including the power unit and the case housing. The more the common mode current in the return path, the less the interference to external conduction is, thereby effectively reducing the interference to the trackside equipment.

The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device, the apparatus and the computer-readable storage medium disclosed by the embodiments correspond to the method disclosed by the embodiments, so that the description is simple, and the relevant points can be referred to the description of the method.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

The method and the device for suppressing the common mode current of the converter and the converter provided by the application are described in detail above. The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the method and the core idea of the present application. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.