Bidirectional converter and insulation design method

Abstract

The invention relates to the field of converters, and discloses a bidirectional converter and an insulation design method.An insulation assembly is additionally arranged between a heat dissipation assembly and a cabinet of a power module of the bidirectional converter to isolate electrical connection between the power module and the cabinet, in this way, the insulation strength of the converter can be enhanced, and the reliability of the converter is improved. And the voltage-withstanding requirements of the converter in different power supply scenes can be met, and the heat dissipation efficiency of the power module is not influenced.

Description

Technical Field

[0001] The present application relates to the field of converters, and in particular to a bidirectional converter and an insulation design method. Background Art

[0002] With the development of rail traction power supply technology, the application of bidirectional converters in rail traction power supply has become a trend. The IGBT module in the bidirectional converter itself has an insulation setting. However, in the rail traction power supply system, the cost of setting an IGBT module that meets the insulation requirements of the system is relatively high, not cost-effective, and the installation process is also complicated. Summary of the invention

[0003] The present application provides a bidirectional converter and an insulation design method to solve the problems of complex insulation setting process and low cost performance.

[0004] The first aspect of the present application provides a bidirectional converter comprising: at least one power module, the power module comprising a heat dissipation component and an IGBT module; the IGBT module is installed on the heat dissipation component, and is used to control the power conversion between the DC side and the AC side of the electric energy in the DC bus; a cabinet, which is used to install at least one of the power modules; at least one insulating component is arranged between at least one of the heat dissipation components and the cabinet, and is used to isolate the electrical connection between each of the power modules and the cabinet.

[0005] In a feasible implementation manner, the heat dissipation component is provided with at least one mounting surface, and the at least one insulation component is distributed on one or more of the at least one mounting surface.

[0006] In a feasible embodiment, the insulation assembly includes an insulation panel and at least one connector; at least one of the connectors is disposed on two symmetrical surfaces of the insulation panel and is used to fix the mounting surface and the cabinet to the insulation panel.

[0007] In a feasible implementation manner, the insulating panel and all the connecting parts are formed integrally.

[0008] In a feasible implementation manner, if all the connecting parts are metal components, the metal components arranged on two symmetrical surfaces are insulated from each other.

[0009] In a feasible implementation manner, the bidirectional converter further includes:

[0010] A grounding component is provided between the ground end of the power module and the zero potential of the bidirectional converter, and is used to stabilize the ground potential of the power module.

[0011] In a feasible implementation manner, the zero potential of the bidirectional converter is a neutral connection point on the DC bus.

[0012] In a feasible implementation manner, the power module further includes a sheet metal component, the sheet metal component and the heat dissipation component share a common ground, and are insulated and connected to the cabinet via the insulation component and are interconnected to the neutral connection point via the grounding component.

[0013] The second aspect of the present application provides an insulation design method for a bidirectional converter, wherein the bidirectional converter includes at least one power module and a cabinet for installing the power module; the power module includes a heat dissipation component and an IGBT module connected to the heat dissipation component; the insulation design method includes: determining insulation parameters based on the insulation withstand voltage requirement of the main circuit in which the bidirectional converter is located; and setting at least one insulation component with an insulation level matching the insulation parameters between each of the heat dissipation components and the cabinet to isolate the electrical connection between each of the power modules and the cabinet.

[0014] In a feasible embodiment, at least one insulating component having an insulation level matching the insulation parameters is provided between each of the heat dissipation components and the cabinet, comprising: at least one insulating component is provided on multiple mounting surfaces of the heat dissipation components, and the mounting surfaces include the bottom, sides and top of the heat dissipation components.

[0015] In the technical solution provided in the present application, an insulating component is added between the heat dissipation component of the power module of the bidirectional converter and the cabinet to isolate the electrical connection between the power module and the cabinet. This method can not only enhance the insulation strength of the converter, but also meet the voltage withstand requirements of the converter in different power supply scenarios. The process is simple, the cost performance is high, and it does not affect the heat dissipation efficiency of the power module itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the first structure of a bidirectional converter in an embodiment of the present application;

[0017] Figure 2 This is a schematic diagram of a second structure of a bidirectional converter in an embodiment of the present application;

[0018] Figure 3 This is a schematic diagram of the third structure of the bidirectional converter in the embodiment of the present application;

[0019] Figure 4 This is a schematic diagram of a fourth structure of a bidirectional converter in an embodiment of the present application;

[0020] Figure 5 This is a fifth structural schematic diagram of a bidirectional converter in an embodiment of the present application;

[0021] Figure 6 Schematic diagram of the flow of the insulation design method of the bidirectional converter in the embodiment of the present application. DETAILED DESCRIPTION

[0022] The present application provides a bidirectional converter and an insulation design method thereof, by adding an insulating component between the power module and the cabinet of the bidirectional converter, so that the insulation strength between the power module and the cabinet plus the insulation strength of the power module itself can meet the insulation withstand voltage requirements of the bidirectional converter in any main circuit, thereby meeting the system testing requirements.

[0023] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] like Figure 1 As shown, the embodiment of the present application provides a bidirectional converter, specifically comprising:

[0025] The power module 110, the cabinet 120 and the insulating component 130, the power module 110 is fixedly installed in the cabinet 120, and the insulating connection is achieved through the insulating component 130, that is, the insulating component 130 is arranged between the power module 110 and the cabinet 120, for achieving the insulating fixation of the power module 110 and the cabinet 120.

[0026] It should be noted that the number of power modules 110 set on the bidirectional converter can be at least one, and the number of insulating components 130 can also be at least one. The specific number of power modules 110 and insulating components 130 can be set according to actual needs. However, no matter how it is set, the power module 110 and the cabinet 120 need to be insulated and isolated by the insulating component 130.

[0027] Furthermore, in order to facilitate the installation and fixation between the power module 110 and the cabinet 120, a mounting surface 111 for installation is provided on the power module 110. The mounting surface 111 can be selected as any surface of the power module 110. The mounting surface 111 here can be understood as an installation panel provided with a connecting structure, and the connecting structure is connected to the insulating component 130.

[0028] In this embodiment, the power module 110 may be provided with at least one mounting surface 111, and the at least one insulating component 130 is distributed on one or more of the at least one mounting surface 111. It is understandable that the mounting surface 111 is actually the bottom, side and top of the heat dissipation component in the power module 110.

[0029] It is understandable that when only one mounting surface 111 is provided on the power module 110, all the insulating components 130 are arranged on the mounting surface 111, and they can be arranged in an evenly distributed manner, or they can be arranged on four sides and a middle position, such as Figure 2 If at least two mounting surfaces 111 are provided, all the insulating components 130 are evenly distributed on the at least two mounting surfaces 111, as shown in FIG. Figure 3 shown.

[0030] In another embodiment, the insulation assembly 130 includes an insulation panel 131 and at least one connector 132; at least one connector 132 is disposed on two symmetrical surfaces (such as Figure 4 a and b) in the figure are used to fix the mounting surface 111 and the cabinet 120 on the insulating panel 131.

[0031] like Figure 4 As shown, the connector 132 is configured as a screw structure protruding from the surface of the insulating panel 313, and the screw structure is evenly distributed on the surface a and the surface b. Of course, it can also be configured as a groove with internal threads.

[0032] In this embodiment, the connector 132 and the insulating panel 131 can be integrally formed or can be two separate structures. If they are two separate structures, a matching structure for mounting the connector 132, such as a groove with an internal thread, is provided on the insulating panel 131. It should be noted that the integral forming process should be understood as being obtained through a wrapping process.

[0033] The connector 132 may be a metal component made of metal material, or an insulating component made of insulating material, and all connectors 132 contain at least some insulating material, and the connectors 132 that are not made of insulating material must be insulated from each other. That is, if all the connectors 132 are metal components, the metal components arranged on two symmetrical surfaces are insulated from each other, such as staggered arrangement.

[0034] In actual applications, the insulating component 130 can also be implemented as a combined structure of an insulating sheath and an insulating bracket, where the insulating sheath wraps the wires on the power module 110, and then the power module 110 is supported inside the cabinet 120 using the insulating bracket so that the power module 110 does not contact the cabinet.

[0035] Furthermore, the insulating component 130 can also be configured to have a multi-layer structure, with the outer layer being a wear-resistant layer and the inner layer being a high temperature resistant insulating material layer. In addition, in order to achieve heat dissipation of the insulating component 130, ventilation holes penetrating the outer layer and the inner layer are also provided to increase air circulation, help dissipate heat and prevent the insulating component 130 from overheating.

[0036] In this embodiment, an insulating component 130 is added between the power module 110 and the cabinet 120. Such a solution is to insulate the power module 110 from the cabinet 120 as a whole. The insulation design is not only simple, but also easy to use in any main circuit scenario. It does not affect the heat dissipation of the power module 110 itself, and can also be insulated.

[0037] like Figure 5 As shown, another embodiment of a bidirectional converter is also provided, the bidirectional converter comprising:

[0038] At least one power module 110, the power module 110 includes a heat dissipation component 112 and an IGBT module 113; the IGBT module 113 is mounted on the heat dissipation component 112, and is used to control power conversion between the DC side and the AC side of the electric energy in the DC bus;

[0039] A cabinet 120, which is used to install at least one of the power modules 110;

[0040] At least one insulating component 130 is disposed between at least one of the power modules 110 and the cabinet 120 , and is used to isolate the electrical connection between each of the power modules 110 and the cabinet 120 .

[0041] The following is an example of a power module. The power module 110 includes at least a heat sink 112 and an IGBT module 113. The IGBT module 113 is connected to the heat sink 112. The heat sink 112 is insulated from the cabinet 120 through the insulation component 130. By setting the insulation component 130 between the heat sink 112 and the cabinet 120, the process is simple and the cost is low. At the same time, such a setting does not require changing the connection between the existing IGBT module 113 and the heat sink 112, and will not affect the original heat dissipation effect. The heat sink 112 includes a high-efficiency heat sink or heat pipe, which can effectively reduce the temperature of the IGBT module 113 while ensuring insulation.

[0042] It should be noted that the IGBT module 113 is fixed to the heat dissipation component 112 by screws or welding, and the heat generated by the IGBT module 113 is transferred to the heat dissipation component 112 for dissipation. The insulation component 130 fixes the heat dissipation component 112 to the cabinet 120 by screws. Although screws are used for fixing, the screws also need to be insulated, such as screws made of insulating materials with required hardness.

[0043] In this embodiment, the power module 110 further includes a drive control component of an IGBT module 113 , a bus capacitor group 114 , and an installation and fixing frame, and the installation and fixing frame is used to install all components and modules in the power module 110 .

[0044] In this embodiment, the connection between the power module 110 and the cabinet 120 is insulated by providing an insulating component 130, which may cause the ground potential of the power module 110, that is, the ground potential of the IGBT module 113 to float, which may have an adverse effect on the control and operation of the IGBT module 113. Therefore, in order to smoothly implement the bidirectional converter provided by the present application, the bidirectional converter also includes: a grounding component 140, which is provided between the ground end of the power module 110 and the zero potential of the bidirectional converter, and is used to stabilize the ground potential of the power module 110, wherein the zero potential of the bidirectional converter is the neutral connection point on the DC bus 115.

[0045] In practical applications, the ground terminal of the power module 110 is interconnected with the neutral point of the three-level DC bus 115 in the bidirectional converter. Since the neutral point potential of the three-level DC bus 115 is 0 V, after being interconnected with the module casing ground at the same potential, the ground potential of the IGBT module 113 can be guaranteed to be 0 V, thereby ensuring the normal operation of the converter.

[0046] In another embodiment, the grounding component 140 can be any conductive conductor, such as a metal wire, a structure, etc., and the heat dissipation component 112 is connected to the neutral point of the DC bus 115, that is, the 0 potential point, through a wire to achieve the stability of the ground potential of the IGBT module 113.

[0047] The power module 110 further includes a sheet metal component. The sheet metal component and the heat dissipation component 112 are grounded together and are interconnected with the neutral connection point through the grounding component 140 .

[0048] In summary, by adding an insulating component between the heat dissipation component of the power module of the bidirectional converter and the cabinet to isolate the electrical connection between the power module and the cabinet, the insulation performance of the IGBT module can be improved at a lower cost to meet the insulation withstand voltage test requirements of the rail transit bidirectional converter system. Compared with the existing solution, the cost can be significantly reduced without affecting the heat dissipation efficiency of the IGBT module, and the installation process is simple.

[0049] See also Figure 6 , is an implementation of an insulation design method for a bidirectional converter provided by the present application, the bidirectional converter includes at least one power module and a cabinet for installing the power module, the power module includes a heat dissipation component and an IGBT module connected to the heat dissipation component; the method includes the following steps:

[0050] 601. Determine insulation parameters based on the insulation withstand voltage requirement of the main circuit where the bidirectional converter is located.

[0051] In this embodiment, by obtaining the design requirements of the main circuit, the insulation parameters of the main circuit are calculated based on the design requirements and preset insulation design rules. The insulation parameters here can be understood as insulation levels.

[0052] Specifically, the specific requirements for insulation withstand voltage of the main circuit are determined according to the current application scenario, rated voltage level, working environment, etc. of the bidirectional converter. Among them, the specific requirements can be obtained through inquiries in the industry's insulation standards and specifications, such as working voltage, transient overvoltage and safety margin. Generally, the withstand voltage of the insulating material and structure should be greater than 1.5 to 2 times the actual use voltage. Considering the bidirectional characteristics of the converter, it also includes a comprehensive evaluation of the voltage, ripple, spikes, etc. in the two working directions.

[0053] It is understandable that the insulation parameters at least include: determining the insulation material and the insulation distance; determining the insulation material includes:

[0054] Choose the appropriate insulating material according to the withstand voltage requirements. Different materials have different breakdown voltages, dielectric constants, and durability. Common insulating materials include: air insulation, which is used in lower voltage and larger spaces; solid insulation, such as epoxy resin, polyester, polyurethane, etc., which is used in high voltage situations; liquid insulation, such as transformer oil, which is used in high voltage and high power equipment. In addition, the mechanical properties, thermal stability, and environmental durability of the material need to be considered, such as performance in humid, high temperature, and corrosive environments.

[0055] Determining the insulation distance includes: calculating and determining the creepage distance and electrical clearance between the electrical components in the main circuit according to the withstand voltage requirements. In addition, factors such as voltage level, environmental pollution level, and relative electrical strength of materials need to be considered. When designing specifically, the insulation coordination standard needs to be referred to for calculation. This standard refers to the insulation marking of the low-voltage system and the creepage distance insulation standard in a polluted environment.

[0056] 602. At least one insulating component with an insulation level and insulation parameters matching each heat dissipation component and the cabinet is provided between each heat dissipation component and the cabinet to isolate the electrical connection between each power module and the cabinet.

[0057] The insulation level is determined based on the insulation parameters, and then the corresponding structural parts are matched from the preset material, component and insulation level correspondence table based on the insulation level, or the design structure requirements of the insulation are calculated, and the corresponding insulation components are designed based on the design structure requirements and set between the power module and the cabinet.

[0058] In this embodiment, at least one insulating component is provided on a plurality of mounting surfaces of the heat dissipation component, and the mounting surfaces include a bottom, a side, and a top of the heat dissipation component.

[0059] In actual applications, when setting up the insulation components, the IGBT module and its heat dissipation components, drive control unit, bus capacitor group and other structures are first combined into a power module as a whole; among them, the bus capacitor group can be set up according to actual design requirements and used as a whole in the power module.

[0060] Then, an insulating component is set between the power module and the cabinet to ensure that there is insulation strength between the power module and the cabinet, ensuring that the overall insulation performance of the power module can meet the main circuit insulation withstand voltage test requirements.

[0061] It should be noted that the insulation component includes multiple layers of insulation material located at the bottom or side of the power module to ensure mechanical and electrical isolation.

[0062] Furthermore, the ground end of the power module interconnects the ground of the IGBT module with the neutral point of the DC bus to avoid adverse effects of ground potential suspension on the control and operation of the converter.

[0063] The potential of the neutral point of the DC bus is 0 V, and the ground potential of the power module can be stabilized through equipotential connection.

[0064] Furthermore, the heat dissipation component can be implemented by using insulating materials with heat dissipation effect, such as thermally conductive insulating glue, which can not only ensure the electrical insulation effect of the power module but also achieve further heat dissipation of the IGBT module.

[0065] The insulating material is a ceramic-based insulator or a high-voltage composite material, which can withstand the high-frequency and high-voltage working environment of the rail transit bidirectional converter.

[0066] Furthermore, the heat dissipation component and the IGBT module of the power module are fixed by a high-efficiency heat sink to ensure that the heat dissipation effect will not be affected by the application of insulating materials.

[0067] In this embodiment, after the insulating component is provided, an electrostatic shielding layer is further provided on the grounding part of the power module to prevent static electricity accumulation and improve the system operation stability.

[0068] In summary, the insulation design method provided in the present application adds an insulating component between the heat dissipation component of the power module of the bidirectional converter and the cabinet, so that the insulation strength between the power module and the cabinet plus the insulation strength of the power module itself can meet the insulation withstand voltage requirements of the bidirectional converter in any main circuit, thereby meeting the system testing requirements.

[0069] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0070] In addition, in the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0071] In the description of the present application, the terms “first”, “second” and “third” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0072] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art who is familiar with the technical field can still modify the technical solutions recorded in the above embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A bidirectional converter, characterized in that: The bidirectional converter comprises: At least one power module, the power module comprising a heat dissipation component and an IGBT module; the IGBT module is mounted on the heat dissipation component and is used to control power conversion between the DC side and the AC side of the electric energy in the DC bus; A cabinet, used for installing at least one of the power modules; At least one insulating component is disposed between at least one of the heat dissipation components and the cabinet, and is used to isolate the electrical connection between each of the power modules and the cabinet.

2. The bidirectional converter according to claim 1, characterized in that: The heat dissipation component is provided with at least one mounting surface, and the at least one insulation component is distributed on one or more of the at least one mounting surface.

3. The bidirectional converter according to claim 2, characterized in that: The insulating assembly includes an insulating panel and at least one connecting member; at least one connecting member is arranged on two symmetrical surfaces of the insulating panel and is used to fix the installation surface and the cabinet on the insulating panel.

4. The bidirectional converter according to claim 3, characterized in that: The insulating panel and all the connecting parts are formed integrally.

5. The bidirectional converter according to claim 3, characterized in that: If all the connecting parts are metal components, the metal components arranged on two symmetrical surfaces are insulated from each other.

6. The bidirectional converter according to any one of claims 1 to 5, characterized in that: The bidirectional converter also includes: A grounding component is provided between the ground end of the power module and the zero potential of the bidirectional converter, and is used to stabilize the ground potential of the power module.

7. The bidirectional converter according to claim 6, characterized in that: The zero potential of the bidirectional converter is the neutral connection point on the DC bus.

8. The bidirectional converter according to claim 7, characterized in that: The power module also includes a sheet metal component, which is grounded to a common ground with the heat dissipation component and is interconnected with the neutral connection point via the grounding component.

9. A method for designing insulation of a bidirectional converter, characterized in that: The bidirectional converter includes at least one power module and a cabinet for installing the power module; the power module includes a heat dissipation component and an IGBT module connected to the heat dissipation component; the insulation design method includes: Determining insulation parameters based on the insulation withstand voltage requirement of the main circuit where the bidirectional converter is located; At least one insulating component having an insulation level matching the insulation parameter is provided between each of the heat dissipation components and the cabinet, so as to isolate the electrical connection between each of the power modules and the cabinet.

10. The insulation design method according to claim 9, characterized in that: The step of providing at least one insulation component whose insulation level matches the insulation parameter between each of the heat dissipation components and the cabinet comprises: At least one insulating component is arranged on a plurality of mounting surfaces of the heat dissipation component, wherein the mounting surfaces include a bottom, a side and an upper portion of the heat dissipation component.

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