Inverter unit and inverter

Abstract

The utility model provides an inverter unit, and the inverter unit (100) comprises a bus capacitor housing (1) which defines an accommodation chamber (10); a bus capacitor module (2), wherein the accommodating chamber is used for accommodating the bus capacitor module; the radiator (3) is fixedly connected to the outer side of the bus capacitor shell, and the radiator is provided with a first surface (31) facing the bus capacitor shell (1) and a second surface (32) opposite to the first surface (31); and a power module (4) fixedly connected to the second surface of the heat sink and electrically connected to the bus capacitor module. The utility model also provides an inverter comprising the inverter unit. The inverter is low in cost and compact in structure, not only can enable the bus capacitor to be fully cooled, but also can reduce the total assembly weight of the power module and the bus capacitor module.

Description

Technical Field

[0001] The utility model relates to the electric drive field of electric vehicles, in particular to an inverter unit and an inverter used in an electric drive system. Background Art

[0002] In the electric drive system of electric vehicles / new energy vehicles, the inverter is the core control unit. The reason why the inverter is so important is that the power battery outputs direct current, which must be converted when supplying power to the motor using alternating current. The quality of the alternating current output by the inverter determines the driving comfort of the electric vehicle, and the efficiency of the inverter largely determines the overall efficiency of the electric vehicle. Therefore, the inverter is the core of the electric vehicle.

[0003] In addition, the power module plays the role of AC-DC conversion in the inverter and is a key electronic device. The bus capacitor is mainly used in the controller to keep the voltage fluctuation of the DC bus within the allowable range and prevent the voltage overcharge and transient voltage from the DC bus from affecting the chip.

[0004] In the existing technical solutions, the power module and the bus capacitor are designed separately, that is, only an independent heat dissipation design is made for the power module, and the bus capacitor cannot share the cooling water channel; and in terms of parts, the shell material of the bus capacitor is mostly engineering plastic; the power module is mostly frame-type, and the radiator material is mostly copper.

[0005] In the above existing designs, the bus capacitor cannot achieve an ideal heat dissipation effect, and the connection assembly between the power module and the bus capacitor is not compact enough, resulting in a larger inverter volume, thereby affecting the overall power density and other performance of the controller. Utility Model Content

[0006] In order to overcome at least one of the above problems, the purpose of the utility model is to provide a low-cost, compact inverter unit, in which the bus capacitor module and the power module share the same heat sink, which not only enables the bus capacitor module to obtain sufficient heat dissipation, but also reduces the volume of the inverter unit.

[0007] To this end, the utility model provides an inverter unit, the inverter unit comprising: a busbar capacitor housing, the busbar capacitor housing defining a housing chamber; a busbar capacitor module, the housing chamber being used to receive the busbar capacitor module; a heat sink, the heat sink being fixedly connected to the outside of the busbar capacitor housing, and the heat sink having a first surface facing the busbar capacitor housing and an opposite second surface; and a power module, the power module being fixedly connected to the second surface of the heat sink and electrically connected to the busbar capacitor module. The inverter unit of this configuration, since the heat sink for the power module is integrated into the busbar capacitor housing, allows the busbar capacitor module to dissipate heat more fully, and reduces the volume of the inverter unit, making the structure more compact.

[0008] According to a preferred embodiment of the present invention, the busbar capacitor housing is constructed in a rectangular parallelepiped shape and has a top wall and a bottom wall opposite to the top wall, the top wall is provided with a groove, such as a rectangular groove, wherein the shape and size of the groove are adapted to the shape and size of the heat sink, the heat sink is correspondingly constructed in a rectangular plate shape, for example, to seal the heat sink to the top wall and cover the groove, and the heat sink is arranged so that there is a gap space between the first surface and the bottom surface of the groove. In one example, the first surface of the heat sink is provided with a plurality of heat dissipation fins extending into the groove to dissipate heat more efficiently.

[0009] In one embodiment of the present invention, the above-mentioned rectangular parallelepiped busbar capacitor housing is configured to have a first side wall and a second side wall along its length direction and a third side wall and a fourth side wall along its width direction, wherein the opening of the accommodating chamber is arranged in the first side wall or the second side wall. Preferably, the first side wall and the second side wall are opposite and parallel, and the third side wall and the fourth side wall are opposite and parallel.

[0010] In a preferred embodiment of the present invention, the busbar capacitor housing also has a first fluid channel and a second fluid channel, wherein the first fluid channel is in fluid communication with the gap space and extends in the third side wall to a first port located in the bottom wall, and the second fluid channel is in fluid communication with the gap space and extends in the fourth side wall to a second port located in the bottom wall, so that the first fluid channel, the gap space and the second fluid channel form a cooling medium channel extending between the first port and the second port. Here, the cooling medium can be, for example, 50% ethylene glycol + 50% water. By providing such a cooling medium channel, the cooling medium flows through the radiator and the busbar capacitor housing at the same time, so that the busbar capacitor module and the power module can be cooled more efficiently at the same time.

[0011] According to a preferred embodiment of the present invention, the busbar capacitor housing and the radiator are both made of aluminum, wherein the radiator is sealedly connected to the top wall of the busbar capacitor housing by friction stir welding. Since the radiator and the busbar capacitor housing are made of aluminum, the cost can be significantly reduced, and the total assembly weight of the inverter unit can also be reduced.

[0012] In one solution of the utility model, since the heat sink is made of aluminum, in order to facilitate the fixed connection of the power module to the heat sink, the second surface of the heat sink is provided with a cold-sprayed copper coating, and the lower surface of the power module is provided with a copper component, so that the power module can be fixedly connected to the second surface of the heat sink by soldering.

[0013] In a preferred embodiment of the present invention, in order to facilitate the assembly of the busbar capacitor module, the opening of the accommodating chamber is a rectangular opening provided in the first side wall, and the busbar capacitor module is installed in the accommodating chamber via the opening. Optionally, a plurality of threaded through holes extending from the top wall toward the accommodating chamber are also provided in the first side wall.

[0014] In the utility model, the busbar capacitor module may include a plurality of capacitor core members arranged at intervals, a positive copper busbar connected to the positive electrodes of the plurality of capacitor core members, and a negative copper busbar connected to the negative electrodes of the plurality of capacitor core members, and the plurality of capacitor core members are encapsulated in the accommodating chamber by insulating and heat-conductive epoxy resin, and the epoxy resin fills the gaps between the plurality of capacitor core members.

[0015] According to one solution of the utility model, the power module is electrically connected to the bus capacitor module through a connecting mechanism, wherein the connecting mechanism includes a positive terminal and a negative terminal of the power module, the positive copper bar and the negative copper bar of the bus capacitor module, and a plurality of threaded fasteners for fixing the positive terminal to the positive copper bar and fixing the negative terminal to the negative copper bar. The negative terminal, the positive terminal, the positive copper bar and the negative copper bar are all provided with threaded through holes, and threaded fasteners such as bolts extend through the corresponding threaded through holes and the threaded through holes in the first side wall of the bus capacitor housing, thereby electrically connecting the power module and the bus capacitor module and fastening them to the bus capacitor housing.

[0016] The utility model also provides an inverter, which comprises the inverter unit and a shell for packaging the inverter unit.

[0017] Due to the adoption of the above-mentioned technical scheme, the inverter unit / inverter of the utility model can produce at least one of the following beneficial technical effects: low cost, the bus capacitor module and the radiator can be supplied by the same supplier, which reduces the assembly cost; the bus capacitor module and the power module share the radiator and the cooling medium channel, so that the bus capacitor module can be fully cooled; the bus capacitor housing and the radiator are made of aluminum, which is not only light in weight, but also reduces the total assembly weight of the inverter unit and further reduces the cost; the radiator is integrated into the bus capacitor housing, making the structure compact, reducing the inverter unit, and thus reducing the size and volume of the inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] With reference to the accompanying drawings, further features and advantages of the present invention will be more clearly understood by reading the following detailed description:

[0019] Figure 1 A perspective view of an inverter unit according to an embodiment of the present utility model is shown;

[0020] Figure 2 for Figure 1 A three-dimensional diagram of a busbar capacitor housing of an inverter unit;

[0021] Figure 3 for Figure 1 An exploded view of the inverter unit is shown;

[0022] Figure 4 for Figure 1 A bottom view of the inverter unit is shown; and

[0023] Figure 5 for Figure 4 CC cross-sectional view of the inverter unit shown. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. In the following description, the descriptions of directions, such as "upper", "lower", "inner", "outer", etc., which may be used, are only for the convenience of description, unless otherwise explicitly stated, and are not intended to form any limitation on the technical solution of the utility model. In addition, terms such as "first" and "second" are used below to describe the elements of the present application. These terms are only used to distinguish the elements without limiting the nature, sequence, order or number of these elements. In addition, it should be noted that in this specification, the same technical features are marked with the same or similar figures.

[0025] The terms "top" and "bottom" are used to describe the relative positioning of features of the present invention. These terms should be understood to refer to Figure 1 and Figure 2 The positioning orientation of the product shown. In the present utility model, the "inverter unit" is a part of the inverter and is the core unit module of the inverter. The inverter according to the present application is mainly used in new energy electric vehicles, but can also be used in photovoltaic fields and frequency converters, etc.

[0026] Figure 1 An embodiment of an inverter unit 100 according to the utility model is shown. In this embodiment, the inverter unit 100 includes a bus capacitor housing 1, a bus capacitor module 2, a heat sink 3, and a power module 4. The heat sink 3 is integrated to the outside of the bus capacitor housing 1, the power module 4 is fixedly connected to the upper surface of the heat sink, the bus capacitor module 2 and the power module 4 share the same heat sink, and the power module 4 is also electrically connected to the bus capacitor module 2.

[0027] Figure 2A stereoscopic view of an embodiment of a busbar capacitor housing 1 is shown, and the busbar capacitor housing 1 is constructed in a rectangular parallelepiped shape and has a top wall 11, a bottom wall 12 opposite to the top wall, a first side wall 13 and a second side wall along its length direction, a third side wall 14 and a fourth side wall 15 along its width direction, and a housing chamber 10 defined by these walls, which is used to receive the busbar capacitor module 2. Advantageously, a groove 111, such as a rectangle, is provided in the top wall 11, and the size of the groove is also selected to match the size of the heat sink. In this embodiment, the groove 111 is preferably a stepped groove defining a circumferential edge / rim 110. In addition, the first side wall 13 visible in the figure is provided with, for example, a rectangular opening 101 leading to the housing chamber 10. It should be understood that the rectangular opening 101 can also be provided in the opposite second side wall. The busbar capacitor housing 1 is usually made of aluminum, which not only meets the process requirements, but also has low cost and light weight.

[0028] Figure 3 for Figure 1 The exploded view of the inverter unit 100 shown in the figure, in order to adapt to the groove 111, the radiator 3 is also correspondingly constructed as a rectangular plate, and the radiator has a first surface (not shown) facing the busbar capacitor housing 1 and an opposite second surface, that is, the upper surface of the radiator. In a preferred embodiment, the radiator 3 is also made of aluminum, so the rectangular plate-shaped radiator 3 can be sealedly connected to the top wall 11 of the busbar capacitor housing 1 by, for example, friction stir welding, specifically, sealed and fixedly connected to the circumferential edge 110 of the groove 111, and after the assembly is completed, there is a gap space g between the first surface (not shown) of the radiator 3 and the bottom surface 112 of the groove 111, and the gap space is suitable for the flow of the cooling medium. In addition, in order to obtain better heat dissipation efficiency, the first surface of the radiator facing the busbar capacitor housing 1 is provided with a plurality of heat dissipation fins, the heat dissipation fins extend into the groove 11, and the length of the heat dissipation fins can be selected to contact the bottom surface 112 or be spaced apart from the bottom surface 112. In this article, "friction stir welding" refers to the use of heat generated by the friction between the high-speed rotating welding tool and the workpiece to partially melt the welded material. When the welding tool moves forward along the welding interface, the plasticized material flows from the front of the welding tool to the back under the action of the rotating friction of the welding tool, and forms a dense solid phase weld under the extrusion of the welding tool. This connection method has mature technology and reliable sealing, does not require screws and sealing rings, and can save materials.

[0029] exist Figure 3 In the above-mentioned embodiment shown, since the heat sink 3 is made of aluminum, in order to be fixedly connected to the power module 4 having a copper component on the lower surface, a cold-sprayed copper coating 321 is provided on the second surface of the heat sink 3 facing away from the bus capacitor housing 1. For example, the cold-sprayed copper coating can be three rectangular areas, so that the power module 4 can be fixedly connected to the second surface of the heat sink by soldering.

[0030] Figure 4 is a bottom view of the inverter unit 100 according to the present invention. Figure 5 for Figure 4 CC sectional view of the inverter unit in FIG. As can be seen from the figure, the inverter unit 100 has a cooling medium channel L shown in dotted lines, which extends between the first port 142 and the second port 152 located in the bottom wall 12 of the busbar capacitor housing 1, and is composed of a first fluid channel 141, a second fluid channel 151, and a gap space g located between the heat sink 3 and the bottom surface of the groove 111. For example, the first fluid channel 141 may include a first inclined section 1411 and a first vertical section 1412 extending in the third side wall 13, wherein the first inclined section 1411 leads to the gap space g, that is, it is fluidly connected to it, and the first vertical section 1412 leads to the first port 142. The second circulation channel 151 may include a second inclined section 1511 and a second vertical section 1512 extending in the fourth side wall 15, wherein the second inclined section 1511 leads to the gap space g, that is, it is fluidly connected to it, and the second vertical section 1512 extends to the second port 152. The above layout of the cooling medium channel L is only exemplary, and other layout forms of fluid channels formed in the side wall of the bus capacitor housing 1 and capable of communicating with the gap space fluid are also included in the scope of the present application. Since the inverter unit has the above configuration, the power module 4 and the bus capacitor module 2 share the same heat sink 3 and the same cooling medium channel L, so as to better achieve heat dissipation of the power module and the bus capacitor module.

[0031] See again Figure 2 and Figure 3 According to one embodiment of the utility model, the busbar capacitor module 2 includes four capacitor core pieces 20, a positive copper bar 21 and a negative copper bar 22 arranged at intervals, wherein these capacitor core pieces 20 are potted into the accommodating chamber 10 via a rectangular opening provided in the first side wall 13 of the busbar capacitor housing 1, for example, by an insulating and heat-conductive epoxy resin, the positive copper bar 21 is electrically connected to the positive electrode of each capacitor core piece 20, and the negative copper bar 22 is electrically connected to the negative electrode of each capacitor core piece 20. The first side wall of the busbar capacitor housing 1 is also provided with a plurality of groups of threaded through holes 130 extending from the top wall 11 toward the accommodating chamber 10, for example, three groups, each group of three threaded through holes. It should be understood that the number of threaded through holes depends on the number of capacitor core pieces and the configuration of the power module, and the number shown in the figure is merely exemplary, and other suitable numbers of threaded through holes selected as needed are also included in the scope of the present application.

[0032] In the above embodiment according to the utility model, the power module 4 can be electrically connected to the bus capacitor module 2 through a corresponding connection mechanism, wherein the connection mechanism includes a positive terminal 41 and a negative terminal 42 of the power module, a positive copper bar 21 and a negative copper bar 22 of the bus capacitor module 2, a threaded through hole 130 in the first side wall, and a threaded fastener 5, such as a bolt. The positive terminal 41, the negative terminal 42, the positive copper bar 21, and the negative copper bar 22 are all provided with corresponding through holes, some bolts pass through the positive terminal, the positive copper bar, and the corresponding threaded through holes in sequence, and other bolts pass through the negative terminal, the negative copper bar, and the corresponding threaded through holes in sequence, so as to electrically connect the power module 4 to the bus capacitor module 2 in a fixed manner.

[0033] The utility model also provides an inverter, which includes the inverter unit 100 mentioned above.

[0034] Although the utility model has been disclosed as a preferred embodiment, the utility model is not limited thereto. Any combination, change and modification made by any person skilled in the art without departing from the spirit and scope of the utility model should be included in the protection scope of the utility model, so the protection scope of the utility model should be based on the scope defined by the claims.

Claims

1. An inverter unit, characterized in that: The inverter unit (100) comprises: A busbar capacitor housing (1), the busbar capacitor housing defining a housing chamber (10); A busbar capacitor module (2), the accommodating chamber being used to receive the busbar capacitor module; a heat sink (3) fixedly connected to the outer side of the bus capacitor housing and having a first surface facing the bus capacitor housing (1) and an opposite second surface; and A power module (4) is fixedly connected to the second surface of the heat sink and electrically connected to the bus capacitor module.

2. The inverter unit according to claim 1, characterized in that: The busbar capacitor housing (1) is constructed in a rectangular parallelepiped shape and has a top wall (11) and a bottom wall (12) opposite to the top wall, the top wall (11) is provided with a groove (111), wherein the shape and size of the groove are adapted to the shape and size of the heat sink so as to seal the heat sink to the top wall and cover the groove (111), and the heat sink is arranged so that a gap space (g) is provided between the first surface and the bottom surface (112) of the groove.

3. The inverter unit according to claim 2, characterized in that: The busbar capacitor housing (1) has a first side wall (13) and a second side wall along its length direction and a third side wall (14) and a fourth side wall (15) along its width direction, wherein the opening (101) of the accommodating chamber (10) is arranged in the first side wall or the second side wall.

4. The inverter unit according to claim 3, characterized in that: The busbar capacitor housing (1) also has a first fluid channel (141) and a second fluid channel (151), wherein the first fluid channel (141) is connected to the gap space fluid and extends in the third side wall (14) to a first port (142) located in the bottom wall (12), and the second fluid channel (151) is connected to the gap space fluid and extends in the fourth side wall (15) to a second port (152) located in the bottom wall (12), so that the first fluid channel, the gap space and the second fluid channel form a cooling medium channel (L) extending between the first port and the second port.

5. The inverter unit according to claim 2, characterized in that: The busbar capacitor housing (1) and the heat sink (3) are both made of aluminum, and the heat sink (3) is sealingly connected to the top wall of the busbar capacitor housing (1) by friction stir welding.

6. The inverter unit according to claim 5, characterized in that: The second surface of the heat sink (3) is provided with a cold-sprayed copper coating (321), and the lower surface of the power module is provided with a copper component, so that the power module (4) can be fixedly connected to the second surface of the heat sink by soldering.

7. The inverter unit according to claim 3, characterized in that: The opening (101) is configured as a rectangular opening provided in the first side wall (13), and the busbar capacitor module (2) is mounted to the accommodating chamber via the opening.

8. The inverter unit according to any one of claims 3 to 5, characterized in that: The busbar capacitor module (2) comprises a plurality of capacitor core members (20) arranged at intervals, a positive copper busbar (21) electrically connected to the positive electrodes of the plurality of capacitor core members, and a negative copper busbar (22) electrically connected to the negative electrodes of the plurality of capacitor core members, wherein the plurality of capacitor core members are encapsulated in the accommodation chamber by insulating and heat-conductive epoxy resin.

9. The inverter unit according to claim 8, characterized in that: The power module (4) is electrically connected to the bus capacitor module (2) via a connecting mechanism, wherein the connecting mechanism comprises a positive terminal (41) and a negative terminal (42) of the power module (4), the positive copper busbar (21) and the negative copper busbar (22) of the bus capacitor module, and a plurality of threaded fasteners (5) for fixedly connecting the positive terminal (41) to the positive copper busbar (21) and for fixedly connecting the negative terminal (42) to the negative copper busbar (22).

10. An inverter, characterized in that: The inverter includes the inverter unit according to any one of claims 1 to 9.

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