Switch unit with additional bracket

Abstract

The switching unit according to the invention comprises: at least one power module mounted on a support, said power module extending in a plane; a spring device; the metal plate presses the spring device on the power module in the vertical direction perpendicular to the plane, and the metal plate only partially covers the power module in the plane.

Description

Technical Field

[0001] The present invention relates to the field of electronics and electrical engineering, and in particular to the field of switch units. Background Art

[0002] A switching unit is a power electronic device that is able to generate an alternating current from a direct current. A switching unit can be integrated into a motor vehicle, in particular a hybrid or electric vehicle, to convert the direct current provided by the battery into an alternating current to power the electric motor.

[0003] The switch unit includes: at least one power module mounted on a heat sink; at least two busbars, each busbar being electrically connected to the power module to supply a DC voltage to the module; and at least one DC link capacitor being electrically connected to the busbars through electrical terminals. The power module contains various power components, and the DC link capacitor acts as a buffer and can balance fluctuations.

[0004] The power module is a component that can heat up to more than 150 degrees Celsius and should be cooled by at least 30 degrees Celsius to improve its efficiency. There is a need to cool the power module more efficiently. Summary of the invention

[0005] The present invention is adapted to this situation by providing a switch unit in which a metal plate, which only partially covers the top side of the power module, is used to press the bottom side of the power module against the heat sink. Thus, the power module is effectively cooled by heat conduction between the top side of the power module and the metal plate, and by leaving some parts of the power module uncovered by the metal plate. Furthermore, the power module is effectively held on the heat sink by the metal plate to improve cooling of the power module by its bottom side.

[0006] The switch unit according to the present invention comprises at least one power module mounted on a support, and further comprises a spring device, a metal plate, wherein the power module extends in a plane, and the metal plate presses the spring device against the power module in a vertical direction perpendicular to the plane.

[0007] The metal plate only partially covers the power module in said plane.

[0008] The switch unit according to the invention is intended for implementation in a vehicle, such as a hybrid or electric vehicle, in order to power an electric motor of the vehicle. According to an optional feature of the invention, the metal plate covers a central area of ​​the power module in said plane.

[0009] The pressure is thus located in the center of the power module and in this simpler solution, there is no need to arrange the pins of the power module outside the power module.

[0010] According to an optional feature of the invention, the metal plate comprises at least one leg extending beyond the power module in said plane, the leg comprising at least one attachment means for attaching the metal plate to the support.

[0011] The attachment means fasten the metal plate to a support, such as a cooling device.

[0012] According to an optional feature of the invention, the gap distance between the pins extending from the power module and the metal plate is in the range of 2 mm to 6 mm, and is advantageously 4 mm.

[0013] According to an optional feature of the invention, the creepage distance between the pins extending from the power module and the metal plate is in the range of 3 mm to 7 mm, and is advantageously 5 mm.

[0014] According to an optional feature of the invention, the metal plate comprises at least one dome extending vertically from an upper surface of the metal plate.

[0015] The dome is a support for the control panel.

[0016] According to an optional feature of the invention, at least two power modules are arranged in the plane in the longitudinal direction, the dome being positioned between the power modules in the longitudinal direction.

[0017] According to an optional feature of the invention, the spring means is formed integrally with the metal plate, the spring means and the metal plate being made from the same material.

[0018] According to an optional feature of the present invention, the spring device includes at least one blade pressed on the power module, the blade is U-shaped, including a central arm and two legs, and the blade makes the middle part of the central arm press on the power module when the metal plate presses the end of the central arm.

[0019] According to an optional feature of the invention, the switch unit comprises: at least two busbars, each busbar being electrically connected to a power module; and at least one DC link capacitor being electrically connected to the busbars, the power module and the DC link being positioned side by side. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other characteristics, details and advantages of the invention will become more apparent on reading the following description on the one hand and with reference to several examples of implementation given by way of illustration and not limitation on the other hand in the attached schematic drawings, in which:

[0021] [ Figure 1 ] is a schematic diagram of a switch unit according to the present invention;

[0022] [ Figure 2 ] shows the metal plate on top of the power module;

[0023] [ Figure 3] is a cross-sectional view of a planar switch unit;

[0024] [ Figure 4 ] shows a U-shaped blade pressed against a power module by a metal plate;

[0025] [ Figure 5 ] is a view of the lower surface of the metal plate. DETAILED DESCRIPTION

[0026] The features, variants and different embodiments of the present invention can be associated with each other in various combinations, as long as they are not incompatible or exclusive of each other. In particular, it is conceivable that the variant of the present invention only includes a selection of the features described subsequently, which does not include other features, if this selection of features is sufficient to give technical advantages and / or distinguish the present invention from the prior art.

[0027] Like numbers refer to like elements throughout the drawings.

[0028] Figure 1 A switch unit 1 according to the invention is shown in a schematic manner. The switch unit 1 is configured to be installed in a vehicle, such as an electric or hybrid vehicle, with the purpose of generating an alternating current suitable for powering a motor of the vehicle. To this end, the switch unit 1 comprises at least one power module 2, which houses various power supply components connected to a DC link capacitor 6 in which energy can be stored. The switch unit shown and disclosed here comprises three power modules 2a, 2b, 2c.

[0029] As shown in the figure, in this embodiment, the power module and the DC link capacitor 6 are positioned side by side. Figure 1 shown.

[0030] The switch unit 1 further comprises an electronic control board 7 for controlling the power modules. For example, the electronic control board 7 extends above the power modules 2a, 2b, 2c.

[0031] The DC link capacitor 6 comprises a body with a capacitive element and two electrical terminals. Each electrical terminal is arranged to be electrically connected to a busbar 60. The busbar is designed to have a DC voltage U DC The busbars 60 are connected to each of the power modules 2a, 2b, 2c to distribute a DC voltage to the power modules.

[0032] For example, each power module is designed to operate at a DC voltage U DCAnd the conversion is performed between the corresponding AC voltage, for example, the AC voltage can be the phase voltage of the motor. As shown in the figure, each power module has, for example, two external AC connectors 21a and 21b, which are designed to provide the AC voltage. In addition to the external AC connectors 21a and 21b, each power module also includes an external connector called positive pole 22 and an external connector called negative pole 23, which are designed to be connected to the positive busbar and the negative busbar, respectively. In the example shown in the figure, two negative external connectors 23 are provided for each power module. These external connectors 21a, 21b, 22, 23 are, for example, in the shape of flat rods.

[0033] To perform voltage conversion, each power module comprises at least one switching arm and therefore two switches connected to each other at a midpoint in the housing 24. The midpoint is connected to the external AC connectors 21a, 21b to provide an AC voltage. The switching arms are connected between the external connectors 22, 23 to provide a DC voltage U DC .

[0034] Each switch is preferably a semiconductor controllable switch, such as a transistor switch, such as a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT) or a gallium nitride field effect transistor (GaNFET).

[0035] Each power module also has a control pin 25 which notably allows the control board 7 to control the switching of the switches.

[0036] The switch unit 1 further includes a heat sink 5 for cooling the power modules 2a, 2b, 2c, on which the power modules 2a, 2b, 2c are mounted. The heat sink 5 includes a cooling chamber 50 defining a coolant flow channel. The cooling chamber 50 has an upper surface 50a and a lower surface 50b, both of which are cooled by the flow of the coolant.

[0037] In the following description, the power module extends in a plane having a rectangular cross-section in the plane. The external AC connector 21 and the external DC connectors 22, 23 extend from opposite sides of the rectangle. The control pins 25 are also aligned along both sides of the rectangle. The central area 20 of the power module is defined as the area around the intersection of the diagonals of the rectangle.

[0038] In the following description, the names "longitudinal", "transverse" and "vertical" refer to the orientation of the switch unit according to the invention. The longitudinal direction corresponds to the direction along which the power modules 2a, 2b, 2c are positioned side by side in a common extension plane of the power modules, the longitudinal direction being parallel to the longitudinal axis L of the coordinate system L, V, T shown in the figure. The transverse direction corresponds to the direction along which each power module 2a, 2b, 2c extends between the side of the external AC connector 21 and the side of the external DC connector 22, 23, the transverse direction being parallel to the transverse axis T of the coordinate system L, V, T and being perpendicular to the longitudinal axis L. Finally, the vertical direction corresponds to the vertical axis V of the coordinate system L, V, T, the vertical axis V being perpendicular to the longitudinal axis L and the transverse axis T. The vertical direction is perpendicular to the extension plane of the power modules 2a, 2b, 2c.

[0039] refer to Figure 2 , the switch unit 1 comprises a metal plate 4, which only partially covers the power modules 2a, 2b, 2c. Figure 3 As shown, a metal plate extends between the control board 7 and the power modules 2a, 2b, 2c.

[0040] The metal plate 4 is attached to a heat sink 5, for example by screws, as will be disclosed below. In a variant, the metal plate may be attached to another support 5 of the power module.

[0041] The spring device 3 is mounted between the metal plate 4 and the power module. The spring device is, for example, fixed to the metal plate. The spring device presses the power module towards the upper surface 50a of the heat sink. For example, for each power module 2a, 2b, 2c, the spring system comprises a flexible blade 30a, 30b, 30c compressed between the metal plate 4 and the power module. In a preferred embodiment, the flexible blade can be fixedly attached to the metal plate.

[0042] In a variant not disclosed here, the spring device 3 may comprise a single blade pressing on the three power modules.

[0043] like Figure 4 As shown, the blades may be arranged at an angle relative to the longitudinal direction.

[0044] The power modules 2a, 2b, 2c are pressed against the upper surface 50a of the heat sink, which improves cooling. Furthermore, the thermal contact between the metal plate 4 and the power modules 2a, 2b, 2c via the spring system 3 provides additional heat removal for the power modules.

[0045] refer to Figure 2, the metal plate 4 comprises a main portion 40 extending in the longitudinal direction. The main portion comprises a cutout 41 in the transverse direction. The cutout is such that it creates a clearance zone around the control pin 25 for each power module, in which the power module is not covered by the metal plate. The metal plate 4 only partially covers the central area 20 of the power module.

[0046] refer to Figure 2 , on the top of each power module, there are two cutouts on opposite longitudinal sides of the plate, which are opposite in transverse direction. The cutouts 41 locally reduce the transverse dimension of the metal plate in the central area 20 of the power module. The cutouts are usually U-shaped or V-shaped.

[0047] The plate comprises at least one leg 42 extending in the extension plane of the power module beyond the power module 2. The leg comprises means 43 as through holes for attaching the metal plate 4 to the heat sink 5 with screws.

[0048] The clearance distance between the pins extending from the power module and the metal plate must be considered, which is the minimum distance between the two parts in the air. This distance must be in the range of 2mm to 6mm, advantageously 4mm. The creepage distance between the pins extending from the power module and the metal plate through the non-conductive part (through the power module) must be in the range of 3mm to 7mm, advantageously 5mm.

[0049] like Figure 5 As shown, the metal plate comprises a dome 44 extending vertically from the upper surface of the main portion 4a of the metal plate. The dome is used to carry the control board 7.

[0050] In a preferred embodiment, the domes are aligned in the longitudinal direction. The domes are positioned between the power modules in the longitudinal direction. This positioning gives rigidity to the control board to avoid its deformation under vibration.

[0051] In a preferred embodiment, the dome can also extend from the lower surface of the main part 4b of the metal plate.Therefore, the length of the dome is sufficient to allow the screw to be guided through the metal plate.

[0052] Figure 5 A particular embodiment is shown, in which the blade is U-shaped, comprising a central arm 31 and two legs 32. The metal plate 4 presses the ends of the central arm towards each other in the longitudinal direction, in such a way that the middle of the central arm presses against the power module.

[0053] Many modifications and other embodiments of the invention set forth herein will come to mind to one skilled in the art to which the invention relates having the benefit of the teachings presented in the foregoing description and the associated drawings. Therefore, it should be understood that the invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A switch unit (1) for a motor vehicle, comprising at least: A power module (2) is mounted on a support (5), the power module extending in a plane, Spring device (3), Metal plate (4), The metal plate (4) presses the spring device (3) onto the power module (2) in a vertical direction perpendicular to the plane. The metal plate (4) only partially covers the power module (2) in the plane.

2. The switch unit according to claim 1, wherein: The metal plate covers a central area of ​​the power module in the plane.

3. A switching unit as claimed in any one of the preceding claims, wherein: The metal plate comprises at least one leg (42) extending beyond the power module (2) in the plane, the leg comprising at least one attachment means (43) for attaching the metal plate (4) to the support (5).

4. A switching unit as claimed in any one of the preceding claims, wherein: The gap distance between the pins extending from the power module and the metal plate is in the range of 2 mm to 6 mm, and is advantageously 4 mm.

5. A switching unit as claimed in any one of the preceding claims, wherein: A creepage distance between the pins extending from the power module and the metal plate is in the range of 3 mm to 7 mm, and is advantageously 5 mm.

6. A switching unit as claimed in any one of the preceding claims, wherein: The metal plate includes at least one dome (44) extending vertically from an upper surface of the metal plate.

7. The switch unit according to claim 6, comprising at least two power modules (2A, 2B) arranged in the longitudinal direction in the plane, The dome (44) is positioned between the power modules along the longitudinal direction.

8. A switching unit as claimed in any one of the preceding claims, wherein: The spring device (3) is formed integrally with the metal plate (4).

9. The switch unit according to claims 1 to 7, wherein: The spring device (3) comprises at least one blade (30) pressed on the power module, the blade being U-shaped and comprising a central arm (31) and two legs (32), and the blade enables the middle part of the central arm (31) to press on the power module (2) when the metal plate (4) presses the end of the central arm.

10. The switch unit according to any one of the preceding claims, further comprising: at least two busbars, each busbar being electrically connected to the power module; and at least one DC link capacitor electrically connected to the busbar, the power module and the DC link being positioned side by side.

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