An elastic element for an electrical power converter

Abstract

This topic relates to an electrical power converter, and more specifically, to an improved mounting of a module within an electrical power converter by means of an elastic element. An electrical power converter (100), according to this topic, comprises a housing (102), a module (112), and a support element (110). The module (112) includes at least one electronic component, said component being in thermal contact with the housing (102). The support element (110) comprises an overmolded body, disposed inside the housing (102). An elastic element (108) is partially overmolded into said body of the support element (110) and exerts pressure on the module (112). The module (112) is pushed, in a direction towards the housing (102) and away from the support element (110), by the elastic element (108), thereby improving the structural and operational integrity of the electrical power converter (100).This topic also concerns an assembly which includes an electrical machine and the electrical power converter (100). Figure for the abstract: Fig. 1.

Description

Title of the invention: An elastic element for an electric power converter Field of invention

[0001] The present subject matter relates generally to an electrical power converter, and more specifically, relates to an improved attachment of a module in an electrical power converter by means of an elastic element.

[0002] Context

[0003] An electrical power converter is a power electronic device or circuit that converts direct current (DC) into alternating current (AC), and / or vice versa. An electrical power converter comprises electronic components, such as power semiconductors, capacitors, etc., configured to electrically communicate with an electrical machine. By virtue of the aforementioned electrical communication, the electrical power converter can transfer control signals to the electrical machine, thereby controlling said machine. During operation, the electrical power converter is susceptible to overheating because the electronic components generate a lot of heat. To combat the overheating problem, the heat generated by the electronic components is dissipated by means of a heat sink in thermal contact with said components.However, there are scenarios in which the heat generated by the electric power converter is not efficiently conducted to the heat sink from the said components. In such scenarios, the electronic components of the electric power converter are likely to fail.

[0004] In such a scenario, the electronic component (e.g., a power semiconductor that generates heat during operation) is pressed onto the heat sink by a clip disposed between said component and the heat sink, the clip merely clamping said component onto the heat sink. The clip, however, is an additional device that requires a separate assembly process. Furthermore, such clips are sensitive to vibration and may loosen upon prolonged exposure to vibratory environments.

[0005] In another scenario, the electronic component (a power semiconductor, for example, which generates heat during operation) is pushed onto the heat sink by a spring plate. The spring plate is sandwiched between the electronic component and a second component of the electrical power converter such that the second component exerts pressure on the spring plate. spring that further pushes the electronic component onto the heat sink. However, as in the scenario explained in the previous paragraph, the spring plate is susceptible to vibrations that can cause unwanted movement of the spring plate in the sandwiched position. This scenario is also disadvantageous because the spring plate is not integrally attached to a component, and therefore can be unreliable under prolonged exposure to vibrations. In addition, existing spring plates are configured in such a way that the forces exerted on them are distributed unevenly, which leads to failure of the spring plate over time. As a result, the risk of overheating is high for conventional electrical power converters. In addition, the normal operation of the electrical machine, with which an electrical power converter is electrically connected, is susceptible to failure.It is therefore imperative that the electrical power converter is protected from any heating problems, which also helps to preserve the integrity of the electrical machine.

[0006] Therefore, the technical solution sought by the present subject consists in optimizing the fixing of the electronic components on the heat sink of an electric power converter, thus improving the efficiency of the heat dissipation. Summary of the invention

[0007] The present subject seeks to solve the aforementioned problem of conventional electrical power converters. The present subject relates to an electrical power converter comprising a housing; a module comprising at least one electronic component, wherein the at least one electronic component is in thermal contact with the housing; and a support member comprising an overmolded body, disposed in the housing, wherein an elastic member is partially overmolded in said body of the support member and exerts pressure on the module in a direction toward the housing and away from the support member. Accordingly, since the elastic member is partially overmolded in the support member, dislocation of the elastic member within the electrical power converter is eliminated. Furthermore, the module is pressed, or pushed, onto the housing and reliable thermal contact is maintained.

[0008] According to one aspect, the elastic member comprises two flat plates, each of said plates being interconnected by a connecting arm.

[0009] In one aspect, the arrangement of the connecting arm axially offsets the second flat plate relative to the first flat plate in a direction parallel to the axis XX\ the axis XX' defining a direction of assembly or disassembly of the electrical power converter.

[0010] In one aspect, the connecting arm extends obliquely between one end of a first flat plate and one end of a second flat plate. Said aspect is not limiting, because the connecting arm can also be arranged or oriented so as to be parallel to the axis XX' and extend between the two flat plates.

[0011] In another aspect, the first flat plate of the resilient member is adapted to urge the module away from the support member and toward a lower cover of the housing.

[0012] In yet another aspect, the second of the two flat plates is overmolded in an electrically insulating material of the support member.

[0013] According to one example, the support element comprises an electrically conductive means overmolded in the electrically insulating material, the electrically conductive means being adapted to transport and distribute electrical energy.

[0014] According to one example, the bottom cover of the housing is a heat sink adapted to disperse heat generated by the at least one electronic component of the module. The bottom cover can therefore serve both as an enclosure for the components within a cavity of the housing and as a heat sink for efficient dissipation of heat into the ambient environment.

[0015] According to one aspect, a thermally conductive material is disposed between the module and the lower cover to provide said thermal contact.

[0016] According to one example, the at least one electronic component of the module is a power semiconductor.

[0017] The present subject matter also relates to an assembly comprising: an electric machine; and an electrical power converter in electrical communication with the electric machine, wherein the electrical power converter is configured according to the preceding description. The structural and operational integrity of the elastic element, configured in the manner described above, being ensured, the electrical power converter, and therefore the assembly, operates without failure.

[0018] In one aspect, the electric machine is a rotating electric machine, an electrical energy source, an electrical energy storage, an electronic control unit, or a combination thereof. Brief description of the drawings

[0019] The features, aspects and advantages of the present invention will be better understood in light of the following description and the accompanying figures. The description refers to the accompanying drawings, in which:

[0020] [Fig.l] illustrates an exploded view of an electrical power converter, in accordance with the present subject;

[0021] [Fig.2] illustrates another perspective of the electric power converter, describing fewer components, in accordance with this subject;

[0022] [Fig.3] illustrates a zoomed view of a support element of the electrical power converter, in accordance with the present subject matter;

[0023] [Fig.4] illustrates an assembled perspective of the electrical power converter shown in [Fig.3], configured in accordance with the present subject matter; and

[0024] [Fig.5] illustrates a sectional view of the electrical power converter, showing a resilient member partially overmolded in the support member, in accordance with the present subject matter.

[0025] The figures are not necessarily to scale, and the size of certain parts may be exaggerated to more clearly illustrate the example shown. In addition, the drawings provide examples and / or examples in accordance with the description, however, the description is not limited to the examples and / or examples provided in the drawings. Detailed description

[0026] The present subject matter generally relates to improving the heat dissipation of an electrical power converter. More specifically, the present subject matter relates to improving the thermal conductivity between a heat generating module and a housing of an electrical power converter. An electrical power converter is normally used in conjunction with an electrical machine, such as a rotating electrical machine, an electrical power source, an electrical power storage, an electronic control unit (ECU), or a combination thereof.

[0027] In the following description, reference is made to the accompanying drawings, which are a part thereof, and in which is shown, by way of illustration, a specific embodiment in which the invention may be practiced. These embodiments are described in sufficient detail to enable a person skilled in the art to practice the invention, and it is understood that the embodiments may be combined, or that other embodiments may be used, and that structural and logical modifications may be made without departing from the scope of the present invention. The following detailed description is therefore not to be construed in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

[0028] [Fig.l] illustrates an electrical power converter 100, according to the present subject matter. The electrical power converter 100, according to the present subject matter, comprises a housing 102, a module 112 in thermal contact with the housing 100, and a support member 110 which enables the aforementioned thermal contact. The module 112, in the illustrated examples, is housed in the cavity 114 of the housing 102. The module 112 comprises at least one electronic component, such as a power semiconductor. More than one such module 112 may be arranged inside the housing 102. Furthermore, as illustrated in [Fig.l], the electrical power converter 100 may also comprise a control module 106 arranged in the cavity 114 of the housing 102. The control module 106 is in the form of a printed circuit board, formed for example by a substrate, on which electronic components are fixed and electrically connected to each other by electrical tracks. An electrical circuit is thus formed to generate one or more electrical signals which in turn make it possible to control the module 112. The substrate may be a printed circuit board (PCB) provided with electrical tracks.

[0029] In normal operation, the at least one electronic component of the module 112 generates heat. To efficiently dissipate the generated heat, the module 112 is pressed onto the housing 102 by the support member 110 so that thermal contact is established between them. More specifically, the support member 110 comprises an elastic member 108 which presses, or exerts pressure, on the module 112. Therefore, the heat generated by the module 112 can be efficiently conducted to the housing 102. Furthermore, by means of fluid circulation, for example air, water or oil circulation, the heat can be dissipated into the environment from the housing 102.

[0030] The support element 110, disposed inside the housing 102, comprises an overmolded body and the elastic member 108 partially overmolded in the aforementioned body. Once assembled, the elastic member 108, secured to the support element 110 by being overmolded, pushes the module 112 towards the housing 102 and away from the support element 110. Consequently, the heat generated by the module 112, or at least one electronic component of the module 112, is conducted towards the housing 102 from which a circulation of cooling fluid, such as air, water, oil, can be provided for heat dissipation. Furthermore, even when exposed to vibration, the elastic element 108 does not detach from the assembled state and, given this structural integrity, efficient thermal conduction between the module 112 and the housing 102 is ensured.Furthermore, efficient cooling of the electric power converter 100 is also achieved.

[0031] In one example, the support member 110 comprises an electrically conductive means, for example an electrical bus bar, overmolded in an electrically insulating material. The electrically conductive means is configured to transport and distribute electrical energy, and thus facilitates normal operation of the electrical power converter.

[0032] In the examples shown, the housing 102 comprises an upper cover 104a and a lower cover 104b. In the assembled state, the control module 106, the support element 110 and the module 112 are sandwiched between the cover upper cover 104a and the lower cover 104b. In said example, the lower cover 104b is a heat sink intended to dissipate the heat generated by at least one electronic component of the module 112. The lower cover 104b therefore has a dual function, one being to function as an enclosure for the components inside the cavity 114; and the second function being that of a heat sink to dissipate the heat generated by the module 112. In said example, the elastic element 108 pushes the module 112 towards the lower cover 104b, or heat sink, thereby reducing the heat conduction distance between the module 112 and the lower cover 104b. Furthermore, during the circulation of the cooling fluid, the heat of the lower cover 104b can then be dissipated.

[0033] [Fig. 2] shows the exploded view of the electric power converter 100 of [Fig. 1], excluding however the top cover 104a and the control module 106 for reasons of simplicity of illustration. The electric power converter 100 may have more than one module 112 configured in the manner described above. The number of modules 112 may vary depending on the application. For example, in an application where the electric power converter 100 is used for a rotating electric machine having a three-phase stator, there may be three such modules 112, each module 112 for each phase of said stator. There may also be another case where the electric power converter 100 is used for a rotating electric machine having a six-phase stator.In the above case, the electrical power converter 100 may comprise three modules 112, each of the three modules 112 controlling two phases of the six-phase stator. The electrical power converter 100, shown in the figures, is an example having three of these modules 112, although the perspective views illustrated in Figures 1 and 2 show only two of the modules 112. 1 and 2 show only two of the three modules 112. Accordingly, each module 112 is associated with a resilient member 108 overmolded in the support member 110. Therefore, as illustrated in [Fig. 2], for each module 112, there is a resilient member 108 integrally secured by means of the overmolding in the support member 108. Thus, once assembled, the modules 112 are pushed towards the bottom cover 104, thereby facilitating thermal contact between the modules 112 and the bottom cover 104b.More specifically, the modules 112 are pushed in a direction parallel to the axis XX\ The axis XX' defines a direction along which the components of the electric power converter 100 are assembled or disassembled. As a result, the heat generated by the modules 112 is efficiently conducted to the bottom cover 104b, or heat sink, and then dissipated to the environment via a cooling fluid, such as water, oil, or air. Therefore, since the members . elastic members 108 are overmolded into the support element 110, the structural integrity of the elastic members 108, and therefore of the assembly, is ensured. In addition, the operational integrity of the electrical power converter 100 is safeguarded because the heat generated by the modules 112 is efficiently dissipated.

[0034] [Fig. 3] illustrates an enlarged perspective of [Fig. 2]. More specifically, [Fig. 3] illustrates an exploded view of the support member 110, the elastic member 108, the module 112 and the lower cover 104b. [Fig. 4] illustrates an assembled view of the components shown in [Fig. 3]. For brevity, [Fig. 3] and [Fig. 4] are described herein in tandem.

[0035] The lower cover 104b may comprise a positioning pin 304 (shown in [Fig. 3]) which allows the module 112 and the support element 110 to be positioned during assembly. The module 112 and the support element 110 may each comprise a perforation 306a, 306b so that during positioning, the positioning pin 304 is caused to pass through said perforations 306a, 306b in a direction along the axis XX\ The axis XX' is therefore an axis defining a direction of assembly, or disassembly. Consequently, any possibility of misalignment during assembly is eliminated. Once assembled, the support element 108 is arranged such that the elastic member 108, overmolded in the overmolded body of the support element 110, rests on the module 108, as illustrated in [Fig.4].The elastic member 108 exerts pressure on the module 108 so that the module 108 is pressed onto the bottom cover 104b which is also a heat sink in one aspect. Heat generated by the module 108, for example a power semiconductor, is then conducted to the bottom cover 104b from which the heat can then be dissipated into the ambient environment.

[0036] In one aspect, the elastic member 108 comprises two flat plates 300 which are generally parallel to an upper surface 400 of the module 112. The arrangement of the two flat plates 300 is such that each of said plates 300 is perpendicular to the axis XX\ In addition, the two flat plates, namely a first flat plate 300 and a second flat plate (not shown in Figures 3 & 4), are connected to each other by a connecting arm 302. In one aspect, the connecting arm 302 extends between one end of the first flat plate 300 and one end of a second flat plate. The connecting arm 302 is arranged such that the two flat plates 300, 500 are moved, or offset, axially relative to each other in a direction parallel to the axis XX. The connecting arm 302 is adapted to transfer a load from one of the two plates 300 to the other.Thus, if a load is exerted on the first flat plate 300, said load is transferred, via the connecting arm 302, to the second flat plate, or a reverse load transfer is possible.

[0037] In another aspect, the first planar plate 300 is in direct contact with the upper surface 400 of the module 112. Thus, once assembled, the first flat plate 300 pushes the module 112 towards the lower cover 104b and away from the support element 110.

[0038] The elastic element 108 is only partially overmolded in the overmolded body of the support element 110. More specifically, in one aspect, the second flat plate of the elastic member 108 is integrally molded in the overmolded body of the support element 100. Thus, once assembled, the pressure exerted on the second flat plate is transferred, via the connecting arm 302 and the first flat plate 300, to the module 112. The module 112 is thus pushed towards the housing 102, and more particularly towards the lower cover 104b (which also constitutes a heat sink according to one aspect), thus allowing the heat generated by the module 112 to be effectively conducted towards the lower cover 104b. From the lower cover 104b, the heat can be dissipated into the ambient air.

[0039] [Fig. 5] shows a cross-sectional view of the electrical power converter 100 according to the present subject matter. [Fig. 5] illustrates a cross-sectional view of the assembled electrical power converter 100 shown in [Fig. 4].

[0040] In accordance with the present subject matter, the elastic member 108 comprises the first flat plate 300, as explained in the description above, and a second flat plate 500, the two aforementioned flat plates 300, 500 being parallel to the upper surface 400 of the module 112. The arrangement of the two flat plates 300 is such that each of said plates 300, 500 is perpendicular to the axis XX\ Furthermore, the connecting arm 302, which connects the two flat plates 300, 500 together, is arranged such that the second flat plate 500 is axially offset relative to the first flat plate 300 along an axis parallel to XX\

[0041] In a non-limiting manner, the connecting arm 302 extends obliquely between the two flat plates 300, 500. In yet another example, the connecting arm 302 may be arranged or oriented so as to be parallel to the axis XX\ and extend between the two flat plates 300, 500. In the example shown, the connecting arm 302 extends obliquely between one end of the first flat plate 300 and one end of the second flat plate 500. Furthermore, in said example, the second flat plate 500 is integrally molded in the overmolded body of the support element 110. Furthermore, a portion of the connecting arm 302 is also overmolded in the overmolded body of the support element 110. The overmolding of the aforementioned portion adds to the structural rigidity of the support element 110 and the elastic element 108.Further, the connecting arm 302 provides flexibility to the elastic member 108 such that, even when exposed to varying pressures or loads, the elastic member 108 can flex such that the support member 110 moves back and forth in the direction parallel to the axis XX\ En . furthermore, the pressure exerted on the first flat plate 300 is uniformly distributed, which eliminates the possibility of deformation of the first flat plate 300. The structural integrity of the elastic element 108 is therefore maintained.

[0042] In one example, a thermally conductive material 502 is disposed between the module 112 and the housing 102, more precisely between a lower surface 500 of the module 112 and the lower cover 104b of the housing 102. Thus, when the elastic member 108 presses on the module 112, optimal thermal contact between the module 112 and the lower cover 104b is achieved. In addition, optimal thermal conduction between the module 112 and the lower cover 104b is achieved because the structural integrity of the elastic member 108, configured in the aforementioned manner, is ensured. Furthermore, as explained in the previous paragraph, the pressure exerted is uniformly distributed on the first flat plate 300.

[0043] The present subject matter also relates to an assembly which comprises an electrical machine (not shown) and an electrical power converter 100 configured in the manner described above. The electrical power converter 100 is adapted to be in electrical communication with the electrical machine. The electrical power converter 100 can therefore control said machine by transferring electrical signals.

[0044] In one example, the electrical machine is a rotating electrical machine, an electrical energy source, an electrical energy storage, an electronic control unit, or a combination thereof.

[0045] In the example where the electrical power converter 100 is electrically connected to a rotating electrical machine, the rotating electrical machine can be controlled to operate as a motor (in a motor mode) or a generator (in a generator mode). It can also be said that the electrical power converter 100 operates as a voltage converter that operates as a rectifier bridge in generator mode and / or as an inverter in motor mode of the rotating electrical machine. Accordingly, the rotating electrical machine, an electromechanical device, preferably polyphase, can convert electrical energy into mechanical energy, or vice versa. A rotating electrical machine, although typically used to drive motor vehicles, can have many applications, such as lawn mowers, drones, pumps, turbines, etc.In a scenario where the rotating electric machine operates as a motor to drive a motor vehicle, the electric power converter 100 receives direct current from an electrical power source, converts the direct current to alternating current, and supplies it to a stator of the rotating electric machine which then interacts with the rotor. In a scenario where the rotating electric machine operates as a generator, for example, when the vehicle . motor is driven by an internal combustion (IC) engine, the rotor of the rotating electrical machine is driven, thus interacting with the stator to generate AC. The AC current can then be converted to DC current, by the electrical power converter 100, to be stored in an electrical power accumulator. The electrical energy source and the electrical energy storage, mentioned in the above scenarios, can be the same.

[0046] In the above-mentioned example, the electrical power converter 100 is included, or integrated, in the rotating electrical machine. However, in another example, the electrical power converter 100, operating in the manner described above, may not be integrated with the rotating electrical machine. In other words, it may exist as a separate component of the rotating electrical machine, yet remain electrically connected to said machine to perform the operations as described in the above example. The present invention is applicable to both examples of electrical power converters.

[0047] Various modifications to the disclosed embodiments, as well as other embodiments of the subject matter, will become apparent to those skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications may be made without departing from the scope of the subject matter herein defined.

Claims

Claims

1. An electrical power converter (100) comprising: - a housing (102); - a module (112) comprising at least one electronic component, wherein the at least one electronic component is in thermal contact with the housing (102); and - a support element (110) comprising an overmolded body, disposed in the housing (102), wherein an elastic element (108) is partially overmolded in said body of the support element (110) and exerts pressure on the module (112) in a direction toward the housing (102) and away from the support element (110).

2. An electrical power converter (100) according to claim 1, wherein the elastic element (108) comprises two flat plates (300; 500), each of said plates (300; 500) being interconnected by a connecting arm (302).

3. An electrical power converter (100) according to claim 2, wherein the arrangement of the connecting arm (302) axially offsets the second flat plate (500) from the first flat plate (300) in a direction parallel to the axis XX\ the axis XX' defining a direction of assembly or disassembly of the electrical power converter (100).

4. An electric power converter (100) according to claims 2 and 3, wherein the connecting arm (302) extends obliquely between one end of a first flat plate (300) and one end of a second flat plate (500).

5. An electric power converter (100) according to any one of claims 2 to 4, wherein the first flat plate (300) of the elastic member (108) is adapted to push the module (112) away from the support member (110) and toward a lower cover (104b) of the housing (102).

6. An electrical power converter (100) according to any one of claims 2 to 5, wherein the second plate (500) of the two flat plates (300; 500) is overmolded in an electrically insulating material of the support element (110).

7. An electrical power converter (100) according to any one of claims 1 to 5, wherein the support member (110) comprises electrically conductive means overmolded in the electrically insulating material, the electrically conductive means being adapted to carry and distribute electrical power.

8. An electrical power converter (100) according to claim 5, wherein the lower cover (104a) of the housing (102) is a heat sink adapted to disperse heat generated by the at least one electronic component of the module (112).

9. An electrical power converter (100) according to claim 5 or 8, wherein a thermally conductive material (502) is disposed between the module (112) and the bottom cover (104b) to provide said thermal contact.

10. An electrical power converter (100) according to any one of claims 1 to 9, wherein the at least one electronic component of the module (112) is a power semiconductor.

11. An assembly comprising: - an electrical machine; and - an electrical power converter (100) in electrical communication with the electrical machine, wherein the electrical power converter (100) is configured according to any one of the preceding claims.

12. An assembly according to claim 11, wherein the electrical machine is a rotating electrical machine, an electrical energy source, an electrical energy storage, an electronic control unit, or a combination thereof.

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