Power electronics module

Abstract

Embodiments of the disclosure relate to a power electronics apparatus. The power electronics apparatus includes at least a first electrically conductive element and a second electrically conductive element. The elements are intended to be at a first electrical potential and at a second electrical potential, respectively. At least a first and second power electronics components are mounted on the first and second elements, respectively, a first portion and a second portion of a sink are mounted on the first conductive element and on the second conductive element, respectively, so as to permit the transfer of heat from each power component to the corresponding portion of the sink through the corresponding conductive element. An electrical insulator is present between each portion of the sink so as to prevent the risk of flashover between the two portions.

Claims

1. A power electronics apparatus, comprising: a first electrically-conductive element and a second electrically-conductive element, intended to be respectively at a first electrical potential and at a second electrical potential; a first power electronics component and a second power electronics component being respectively mounted on the first and second elements; and a first portion and a second portion of a heatsink being respectively mounted on the first conductive element and on the second conductive element so as to enable the transfer of calories from each power component towards the corresponding portion of the heatsink throughout the corresponding conductive element, said portions of the heatsink including a first end located on the side of said elements and a second end, opposite to the first end, the first conductive element and the first portion of the heatsink being electrically insulated from the second element and from the second portion of the heatsink, via an electrical insulator, wherein each portion of the heatsink includes a lateral face oriented in the direction of the other portion of the heatsink, the electrical insulator being accommodated between said lateral faces of said portions of the heatsink, said lateral faces diverging from each other in the direction of the second end.

2. The power electronics apparatus according claim 1, further comprising a third conductive element, intended to be at a third electric potential and electrically insulated from the first and second conductors, the third conductive element having no power electronics components and being separate from the heatsink.

3. The power electronics apparatus according to claim 1, wherein each first conductive element and second conductive element are connected to the corresponding portion of the heatsink via a stack of at least two thermomechanical transition layers, said layers made of different materials within the same stack and having thermal expansion coefficients increasing in the direction of the corresponding portion of the heatsink.

4. The power electronics apparatus according to claim 2, comprising a first layer of an electrically-conductive material forming the third conductive element and a second layer of an electrically-conductive material, forming the first and second elements, the second layer being interposed between the first layer and the heatsink, the second layer including bosses passing through the first layer, the power components being mounted on said bosses, an electrical insulator being located between the first layer and the second layer and between the first and second conductive elements of the second layer.

5. The power electronics apparatus according to claim 1, wherein the electrical insulator accommodated between said lateral faces of said portions of the heatsink includes an epoxy resin.

6. The power electronics apparatus according to claim 1, wherein each portion of the heatsink includes fins, each lateral face being formed at least partially on a fin.

7. The power electronics apparatus according to claim 1, wherein each lateral face is planar or rounded.

8. The power electronics apparatus according to claim 1, wherein a distance between the second ends of the lateral faces of the two portions of the heatsink is in the range of between 3 mm and 15 mm.

9. The power electronics apparatus according to claim 1, wherein said apparatus is of the bridge arm type.

10. A turbine engine including a power electronics apparatus according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 is a schematic sectional view of a power electronics module according to a first embodiment of the prior art,

(2) FIG. 2 is a schematic sectional view of a power electronics module according to a second embodiment of the prior art,

(3) FIG. 3 is a schematic sectional view of a power electronics module according to a third embodiment of the prior art,

(4) FIG. 4 is a schematic top view of a power electronics module according to a first embodiment of the invention,

(5) FIG. 5 is a schematic sectional view of the power electronics module of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIGS. 4 and 5 illustrate a power electronics module 1 including first and second layers 30, 31 of an electrically-conductive material, for example copper.

(7) The second layer 31 includes bosses 32 passing through the first layer 30, semiconductor power electronics components 2 being mounted on said bosses 32.

(8) The second layer 32 includes at least two tracks or electrically-conductive elements, respectively a first element 33 and a second element 34, separated from each other by an electrically-insulating material 35.

(9) The first layer 30 forms a third track or electrically-conductive element 36. The first layer 30 is also separated from the second layer 31 by the electrically-insulating material 35.

(10) For example, the first element 33 is at an electric potential denoted +DC, for example in the range of 800 V. The second element 34 forms a phase whose potential may vary and be for example at 800 V or at 0 V. For example, the third element 36 is at an electric potential denoted DC, for example in the range of 0 V.

(11) Wiring wires 16 ensure electrical connections between the components 2 and/or the different elements 33, 34, 36 mentioned before. The power electronics module 1 may also include connectors, not shown, connected to the different elements 33, 34, 35.

(12) For example, the power components 2 are formed by transistors or diodes, for example components of the MOSFET or IGBT type. These components 2 release heat in operation, which should be evacuated.

(13) For this purpose, the module 1 includes a heatsink 4, for example made of aluminium, including a first portion 4a and a second portion 4b separated from each other by an insulating material 37, which herein is a material different from the insulating material 35 separating the different elements. The insulating material 37 is for example an epoxy resin whereas the insulating material 35 is for example an FR4 type insulator, such as an insulator commonly used for the manufacture of printed circuits.

(14) Each portion 4a, 4b of the heatsink 4 includes a base 4c from which fins 5 intended to exchange heat with a cooling fluid extend.

(15) The base 4c of the first portion 4a includes a planar surface forming a first end 38, connected to the first element 33, via a first stack 40 of thermomechanical transition layers. Similarly, the base 4c of the second portion 4b includes a planar surface forming a first end 38, connected to the second element 34, via a second stack 41 of thermomechanical transition layers. The free ends of the fins form the second ends 39 of the portions 4a, 4b of the heatsink 4.

(16) Each stack of layers 40, 41 includes at least two layers, made of different materials within the same stack and having thermal expansion coefficients increasing in the direction of the corresponding portion 4a, 4b of the heatsink 4.

(17) Such a stack of transition layers 40, 41 allows limiting the camber effect according to temperature, without substantially impacting the transfer of calories towards the heatsink 4. The transition layers do not act as an electrical insulator or conductive insulator.

(18) The transition layers may be made of materials identical or similar to those described in the document FR 3 061 989.

(19) The two stacks of layers 40, 41 are separated from each other by the insulating material 37. As shown in FIG. 5, each portion 4a, 4b of the heatsink 4 includes a planar lateral face 42 oriented in the direction of the other portion 4b, 4a of the heatsink 4, said lateral faces 42 diverging from each other in the direction of the second end 39.

(20) The distance d between the second ends 39 of the lateral faces 42 of the two portions 4a, 4b of the heatsink 4 is comprised between 3 and 15 mm.

(21) For example, this distance d is comprised between 3 and 8 mm, for example in the range of 5 mm when the cooling fluid is oil.

(22) For example, this distance d is comprised between 8 and 15 mm, for example in the range of 11 mm when the cooling fluid is air, in particular filtered air.

(23) In operation, heat is produced by the power components, the calories being evacuated by the first and second portions of the heatsink 4 throughout the first and second elements 33, 34 and the stacks of transition layers 40, 41. The presence of the thermal insulators 35, 37 ensures electrical insulation between the different potentials of the module 1. Moreover, the fact that the lateral faces 42 of the two portions 4a, 4b of the heatsink 4 diverge from each other allows increasing the distance between these two lateral faces 42 in the direction of the second end 39, so as to avoid the risk of electric arcs between the two portions 4a, 4b through the cooling fluid. Indeed, in the absence of such a structure, an electric arc could occur given the high potential differences between the two portions 4a, 4b of the heatsink 4.