Electronic power module

Abstract

The present disclosure relates to an electronic power module (10) for an electric motor, the electronic power module (10) comprising: - at least one electronic component, - a package (4) delimiting an interior volume (41) accommodating the at least one electronic component, - an encapsulating material at least partially filling the interior volume (41) of the package (4), wherein the package (4) comprises at least one injection opening (44) for injecting the encapsulating material and at least one degassing opening (45) configured to allow degassing of the encapsulating material from the interior volume (41) to the outside of the package (4), and wherein the package (4) is made in one piece.

Description

Description Title: POWER ELECTRONIC MODULE Technical field

[0001] The present disclosure relates to the field of power electronic modules for the conversion of electrical energy. Such modules are intended in particular for the power supply of electrical equipment, in particular in the field of aeronautics. Prior art

[0002] Figure 1 illustrates a power electronic module. Generally, a power electronic module comprises power electronic components 2 that enable electrical equipment to be supplied with power from an electrical network. Power electronic components are, for example, semiconductor chips forming switching devices, such as for example semiconductor transistors, which are controlled by an electronic control unit.

[0003] The power electronic components 2 are mounted on a substrate 3, for example an SMI type substrate (abbreviated from “insulated metal substrate”). The substrate 3 has a plate shape. The substrate 3 is conventionally mounted on a sole plate 6. In addition, power connection means 7 allow the power electronic components 2 to be connected to the electrical network and control connection means 8 allow the electronic control unit to send signals in order to control the power electronic components 2.

[0004] The whole is conventionally encapsulated in a housing 4, also called a “ring-frame” in English, which is mounted on the sole 6 and which is embedded in an encapsulation material 5, such as resin, in order to mechanically protect the elements of the electronic power module and to improve its thermal behavior.

[0005] Furthermore, since the power electronic module emits heat during operation, it is common to implement a heat sink 9 secured to the substrate 3 in order to evacuate the heat produced for proper operation of the power electronic module.

[0006] More precisely, the housing 4 generally comprises an upper wall 42 and side walls 43 extending from the upper wall 42 so as to encapsulate the power electronic components 2. In other words, the upper wall 42 and the side walls 43 delimit an interior volume 41 intended to receive the power electronic components 2. The upper wall 41 is in particular substantially parallel to the plane of the substrate 3 and arranged opposite the substrate 3 relative to the electronic components 2.

[0007] A window is provided in the upper wall 41 to allow the injection of the encapsulation material 5 and the degassing of the encapsulation material, generally carried out under vacuum, in order to prevent the appearance of bubbles in the encapsulation material. These bubbles can in particular negatively impact the voltage resistance and the longevity of the power electronic module.

[0008] A cover covers the window to protect the power electronics module from possible mechanical shocks and intrusions due to debris, also called "foreign object debris" in English, and to protect the power electronics module from handling errors during assembly of the power electronics module. The cover is generally glued to the housing, which requires a bonding and drying time that can be long. In addition, the cover can come off in the event of module failure due to overpressure in the power electronics module and itself becomes debris that can damage other elements in its environment.

[0009] There is a need to improve the mechanical strength, facilitate manufacturing and reduce the production costs of the means of injecting and degassing the encapsulation material for a power electronic module housing. Summary

[0010] This disclosure improves the situation.

[0011] An electronic power module for an electric motor is proposed. The electronic power module comprises at least one electronic component, a housing delimiting an interior volume housing said at least one electronic component and an encapsulation material at least partially filling the interior volume of the housing. The electronic power module may for example comprise one or more electronic components. The electronic component forms in particular a power electronic component. The housing comprises at least one orifice for injecting the encapsulation material and at least one degassing orifice configured to allow degassing of the encapsulation material from the interior volume to the exterior of the housing. The housing is made in a single piece.

[0012] By the housing comprises at least one orifice for injecting the encapsulating material and at least one degassing orifice, it is meant that the housing comprises at least two separate orifices, at least one of which is intended for injecting the encapsulating material, and at least one other is intended for degassing.

[0013] A housing made from a single piece is understood to mean that the at least one injection orifice and the at least one degassing orifice are made in a wall of the housing. In other words, the at least one injection orifice and the at least one degassing orifice are not made in a separate part which would be fixed to the housing.

[0014] The implementation of at least one injection orifice and at least one degassing orifice on the housing made from a single piece, advantageously makes it possible to have a housing in a single piece which performs the functions of injection and degassing of the encapsulation material. This configuration makes it possible to facilitate the manufacture of the housing compared to the configuration where the housing comprises a window and a cover to cover the window. Indeed, compared to this conventional configuration, the present disclosure offers the advantage of limiting the number of parts to be supplied, of reducing assembly operations, of facilitating handling and consequently of limiting the manufacturing costs of the power electronic module. In addition, the housing according to the present disclosure has improved mechanical strength compared to the classic configuration, because there is no cover that could come off during operation.

[0015] The features set out in the following paragraphs may, optionally, be implemented independently of each other or in combination with each other.

[0016] The power electronic module comprises in particular a substrate on which said at least one electronic component is mounted. The power electronic module may further comprise a base, i.e. a support plate, on which the substrate is mounted. The housing is in particular fixed to the substrate, or to the base where applicable, so as to encapsulate said at least one electronic component. According to this configuration, it is understood that the housing forms a separate part from the substrate, or from the base where applicable.

[0017] Advantageously, the housing comprises an upper wall facing said at least one electronic component and side walls extending from the upper wall at the periphery of the latter. The upper wall and the side walls delimit said interior volume. The upper wall has in particular a planar shape. The side walls extend in particular substantially perpendicular to the upper wall.

[0018] In particular, said at least one injection orifice and said at least one degassing orifice can pass through the upper wall of the housing. This characteristic advantageously makes it easier to produce the injection and degassing orifices because they are arranged in the upper wall which offers a large available surface area. In addition, this configuration makes it easier to inject the encapsulation material, because it is produced directly opposite said at least one electronic component.

[0019] Said at least one injection orifice preferably has a circular section. This shape is simpler to manufacture by machining.

[0020] Said at least one injection orifice may have another cross-sectional shape, for example a square cross-section, a hexagonal cross-section. The cross-sectional shape may advantageously allow for a better injection rate for manufacturing the housing by injection molding, in particular of plastic.

[0021] Said at least one injection orifice may comprise a single injection orifice. This characteristic advantageously makes it possible to limit the number of entry points for the injection of the encapsulation material and thus to facilitate the carrying out of this injection. The single injection orifice may in particular have a substantially central position relative to the upper wall of the housing. Thus, the injection of the encapsulation material is carried out in a more homogeneous manner.

[0022] Alternatively, said at least one injection port may comprise several injection ports, for example two injection ports. This feature makes it possible to distribute the injection points of encapsulation material when appropriate.

[0023] Advantageously, said at least one injection orifice has a surface area smaller than the largest dimension of the smallest debris considered, for example the smallest screw used in the electric motor. The injection orifice thus has a sufficiently small surface area to limit the risks of intrusion of debris through the injection orifice. The surface area of ​​the injection orifice must, however, be sufficiently large to allow the injection of the encapsulating material through the injection orifice.

[0024] Said at least one degassing orifice preferably has a circular section. This shape is simpler to manufacture by machining.

[0025] Said at least one degassing orifice may have another cross-sectional shape, for example a square cross-section, a hexagonal cross-section. The cross-sectional shape may advantageously allow for a better injection rate for manufacturing the housing by injection molding, in particular of plastic.

[0026] Said at least one degassing orifice comprises one or, preferably, a plurality of degassing orifices, for example between four and twenty degassing orifices.

[0027] The degassing orifices may be arranged, in particular in a regular manner, around the at least one injection orifice in order to facilitate degassing.

[0028] When the housing has two injection orifices, the degassing orifices can in particular be arranged around an area, for example circular, which includes the two injection orifices.

[0029] Advantageously, the plurality of degassing orifices are distributed symmetrically with respect to an axis of a plane of the upper wall of the housing. This characteristic advantageously makes it possible to improve the efficiency of the degassing operation.

[0030] Advantageously, said at least one degassing orifice has a surface area smaller than the largest dimension of the smallest debris envisaged, for example the smallest screw used in the electric motor. The at least one degassing orifice thus has a surface area large enough to allow effective degassing of the encapsulating material and sufficiently restricted to limit the risks of intrusion of debris through the at least one degassing orifice.

[0031] The power electronics module may comprise a sealing film covering said at least one injection port and said at least one degassing port. The sealing film makes it possible to protect the power electronics module from intrusion of humidity, possible debris or dust through the injection and degassing ports.

[0032] The sealing film is particularly flexible. The sealing film can, for example, form a label.

[0033] The sealing film can be glued to the case, especially on the top wall of the case.

[0034] The sealing film may further be positioned on the housing or be intrinsically configured to result in the formation of a rupture zone at a predetermined location. This feature allows to control the rupture of the sealing film or the direction of its detachment if necessary towards a surrounding area of ​​lower criticality.

[0035] We understand that we therefore have two rupture configurations.

[0036] In a first rupture configuration, the positioning of the sealing film at a zone subject to greater thermo-mechanical stress, for example, will be the cause of the rupture. More precisely, a portion of the sealing film may be positioned opposite an orifice so that this portion of the sealing film breaks or peels off first.

[0037] In a second configuration, the sealing film itself comprises a rupture zone, for example in the form of a slit, so that the rupture or detachment of the sealing film initiates at this rupture zone.

[0038] In particular, the sealing film may comprise a plurality of slots, each slot being arranged opposite one of the injection or degassing orifices. The slots, for example comprising four slots, may in particular be distributed circularly in a regular manner around an axis, the slots extending in a radial direction relative to said axis. The axis may in particular correspond to a center of the orifice opposite which the slots are arranged.

[0039] According to another aspect, an electric motor is provided comprising at least one electronic power module as previously described.

[0040] The electric motor can be a turbomachine electric motor, a generation electric motor or even a propulsion electric motor.

[0041] The electric motor may in particular comprise a plurality of such power electronic modules arranged circularly around an axis of rotation of the electric motor. The power electronic module according to the present disclosure is all the more suitable for such an electric motor configuration because the power electronic modules face each other. Indeed, in the conventional configuration with a window and a hood, an ejected hood could damage another of the power electronic modules. In the present disclosure, this risk is advantageously limited.

[0042] In this configuration, the upper part of the housing faces the axis of rotation. The normal to the plane of the upper part is preferably substantially radial to the axis of rotation.

[0043] According to another aspect, there is provided a propulsion engine comprising an electric motor as previously described.

[0044] According to another aspect, the present disclosure relates to a method of manufacturing a power electronic module as previously described. The method comprises the following steps: - obtaining the box as previously described, - injecting the encapsulating material into the interior volume of the housing through said at least one injection orifice, - vacuum degassing of the encapsulation material from the interior volume of the housing and through at least one degassing orifice.

[0045] The method may comprise a step of mounting the sealing film on the housing so as to cover said at least one injection orifice and said at least one degassing orifice. Brief description of the drawings

[0046] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which:

[0047] [Fig. 1] schematically illustrates a power electronic module.

[0048] [Fig. 2] schematically illustrates three partial views (Figures 2A, 2B and 2C) of a power electronic module according to one embodiment.

[0049] [Fig. 3] schematically illustrates a view of a shutter film according to one embodiment.

[0050] [Fig. 4] schematically illustrates two views of an electric motor comprising a power electronic mold according to one embodiment. Description of the embodiments

[0051] Generally speaking, Figure 1 schematically illustrates an electronic power module 10 for an electric motor 1 according to the present disclosure. The electric motor may in particular be a turbomachine electric motor, a generation electric motor or even a propulsion electric motor.

[0052] The electronic power module 10 comprises at least one electronic component 2, a housing 4 delimiting an interior volume 41 housing said at least one electronic component 2 and an encapsulation material 5, in particular resin, at least partially filling the interior volume 41 of the housing 4.

[0053] The electronic power module 10 comprises in particular a substrate 3 on which said at least one electronic component 2 is mounted. The electronic power module 10 may further comprise a base plate 6, i.e. a support plate, on which the substrate 3 is mounted. The housing 4 is in particular fixed to the substrate 3, or to the base plate 6 where appropriate, so as to encapsulate said at least one electronic component 2.

[0054] In addition, power connection means 7 allow the electronic components 2 to be connected to the electrical network and control connection means 8 allow an electronic control unit to send signals in order to control the electronic components 2.

[0055] The power electronic module 10 may for example comprise one or more electronic components 2. The electronic component notably forms a power electronic component.

[0056] Furthermore, since the power electronic module emits heat during operation, it is common to implement a heat sink 9 secured to the substrate 3 in order to evacuate the heat produced for proper operation of the power electronic module 10.

[0057] Advantageously, the housing 4 may comprise an upper wall 42 facing said at least one electronic component 2 and side walls 43 extending from the upper wall 42 at the periphery of the latter. The upper wall 42 and the side walls 43 delimit said interior volume 41. The upper wall 42 has in particular a planar shape. The side walls 43 extend in particular substantially perpendicular to the upper wall 42.

[0058] Reference is now made to Figure 2 schematically representing three partial views (Figure 2A, 2B and 2C) of the power electronic module 10.

[0059] The housing 4 comprises at least one injection orifice 44 for the encapsulation material 5 and at least one degassing orifice 45 configured to allow degassing of the encapsulation material 5 from the interior volume 41 to the exterior of the housing 4. The housing 4 is made in one piece.

[0060] By the housing 4 comprises at least one injection orifice 44 of the encapsulation material 5 and at least one degassing orifice 45, it is meant that the housing 4 comprises at least two separate orifices, at least one of which is intended for the injection of the encapsulation material, and at least one other is intended for degassing.

[0061] In particular, the term "case made in one piece" means that the at least one injection orifice 44 and the at least one degassing orifice 45 are made in a wall of the case. In other words, the at least one injection orifice and the at least one degassing orifice are not made in a separate part that would be fixed to the case. It is also understood that the case 4 forms a separate part from the substrate 3, or from the sole 6 where appropriate.

[0062] The implementation of at least one injection orifice and at least one degassing orifice on the housing made from a single piece, advantageously makes it possible to have a housing in a single piece which performs the functions of injection and degassing of the encapsulation material. This configuration makes it easier to manufacture the housing compared to the configuration where the housing comprises a window and a cover to cover the window. Indeed, compared to this conventional configuration, the present disclosure offers the advantage of limiting the number of parts to be supplied, reducing assembly operations, facilitating handling and consequently limiting the manufacturing costs of the power electronic module. In addition, the housing according to the present disclosure has improved mechanical strength compared to the conventional configuration, because there is no cover that risks coming off during operation.

[0063] Advantageously, said at least one injection orifice 44 and said at least one degassing orifice 45 pass through the upper wall 42 of the housing 4. This characteristic advantageously makes it easier to produce the injection orifices 44 and degassing orifices 45 because they are arranged in the upper wall 42 which offers a large available surface area. In addition, this configuration makes it easier to inject the encapsulation material 5, because it is carried out directly opposite said at least one electronic component 2.

[0064] Said at least one injection orifice 44 preferably has a circular section. This shape is simpler to manufacture by machining.

[0065] Said at least one injection orifice 44 may have another cross-sectional shape, for example a square cross-section, a hexagonal cross-section. The cross-sectional shape may advantageously allow for a better injection rate for manufacturing the housing by injection molding, in particular of plastic.

[0066] Said at least one injection orifice 44 may comprise a single injection orifice 44. This characteristic advantageously makes it possible to limit the number of entry points for the injection of the encapsulation material 5 and thus to facilitate the carrying out of this injection. The single injection orifice 44 may in particular have a substantially central position relative to the upper wall 42 of the housing 4. Thus, the injection of the encapsulation material is carried out in a more homogeneous manner.

[0067] Alternatively, said at least one injection orifice 44 may comprise several injection orifices (not shown in the figures), for example two injection orifices. This characteristic makes it possible to distribute the injection points of encapsulation material 5 when appropriate.

[0068] Said at least one injection orifice 44 preferably has a surface area Si smaller than the largest dimension of the smallest debris envisaged, for example of the smallest screw used in the electric motor. The injection orifice 44 thus has a sufficiently small surface area to limit the risks of intrusion of debris through the injection orifice. The surface area of ​​the injection orifice must however be sufficiently high to allow the injection of the encapsulation material through the injection orifice.

[0069] Said at least one degassing orifice 45 preferably has a circular section. This shape is simpler to manufacture by machining.

[0070] Said at least one degassing orifice 45 may have another cross-sectional shape, for example a square cross-section, a hexagonal cross-section. The cross-sectional shape may advantageously allow for a better injection rate for manufacturing the housing by injection molding, in particular of plastic.

[0071] Said at least one degassing orifice 45 comprises one or, preferably, a plurality of degassing orifices, for example between four and twenty degassing orifices. In the example illustrated in FIG. 2, the housing comprises eight degassing orifices.

[0072] The degassing orifices 45 may be arranged, in particular in a regular manner, around the at least one injection orifice in order to facilitate degassing.

[0073] When the housing has two injection orifices, the degassing orifices can in particular be arranged around an area, for example circular, which includes the two injection orifices.

[0074] Advantageously, the plurality of degassing orifices are distributed symmetrically with respect to an axis Y1, Y2 of a plane of the upper wall 42 of the housing 4. In particular, in the example of an electronic power module illustrated in FIG. 2, the degassing orifices are distributed symmetrically with respect to two axes Y1 and Y2 perpendicular to each other and in the plane of the upper wall 42 of the housing 4. This characteristic advantageously makes it possible to improve the efficiency of the degassing operation.

[0075] Advantageously, said at least one degassing orifice 45 has a surface area Sd smaller than the largest dimension of the smallest debris envisaged, for example of the smallest screw used in the electric motor. The at least one degassing orifice 45 thus has a surface area large enough to allow effective degassing of the encapsulating material and sufficiently restricted to limit the risks of intrusion of debris through the at least one degassing orifice 45.

[0076] The electronic power module 10 may comprise a sealing film 50 covering said at least one injection orifice 44 and said at least one degassing orifice 45. The sealing film 50 makes it possible to protect the electronic power module from intrusions of humidity, possible debris or dust through the injection and degassing orifices.

[0077] The sealing film 50 is particularly flexible. The sealing film can particularly form a label.

[0078] The sealing film 50 can be glued to the housing 4, in particular on the upper wall 42 of the housing 4.

[0079] The sealing film 50 may further be positioned on the housing 4 or be intrinsically configured so as to lead to the formation of a rupture zone at a predetermined location. This feature makes it possible to control the rupture of the sealing film or the direction of its detachment, if necessary, towards a surrounding zone of lower criticality.

[0080] We understand that we therefore have two rupture configurations.

[0081] In a first rupture configuration, the positioning of the sealing film at a zone subject to greater thermo-mechanical stress, for example, will be the cause of the rupture. More precisely, a portion of the sealing film may be positioned opposite an orifice so that this portion of the sealing film breaks or peels off first.

[0082] In a second configuration, the sealing film itself comprises a rupture zone, for example in the form of a slit, so that the rupture or detachment of the sealing film initiates at this rupture zone.

[0083] In particular, with reference to FIG. 3, the sealing film 50 may comprise a plurality of slots 51, each slot being arranged opposite one of the injection or degassing orifices. The slots may in particular be distributed circularly in a regular manner around an axis, the slots extending in a radial direction relative to said axis. The axis may in particular correspond to a center of the orifice opposite which the slots are arranged.

[0084] In particular, in the example illustrated in Figure 3, the sealing film 50 comprises four slots 51 distributed circularly in a regular manner around the center of the injection orifice opposite which the slots are arranged. The position of the injection orifice is shown in dotted lines in Figure 3.

[0085] With reference to Figure 4, according to another aspect, the present disclosure relates to an electric motor 1. The electric motor 1 comprises at least one electronic power module 10 as previously described, in particular arranged on an element 110 of the electric motor 1. In addition, the electric motor conventionally comprises a stator 120 and a rotor 130 movable in rotation relative to the stator along an axis of rotation X.

[0086] The electric motor 1 may in particular comprise a plurality of such electronic power modules 10 arranged circularly around the axis of rotation X of the electric motor 1. The electronic power module 10 according to the present disclosure is all the more suitable for such an electric motor configuration because the electronic power modules face each other. Indeed, in the conventional configuration with a window and a hood, an ejected hood could damage another of the electronic power modules. In the present disclosure, this risk is advantageously limited.

[0087] In this configuration, the upper part 42 of the housing 4 notably faces the axis of rotation X. The normal to the plane of the upper part 42 is preferably substantially radial to the axis of rotation X.

[0088] According to another aspect, there is provided a propulsion engine comprising an electric motor 1 as previously described.

[0089] According to another aspect, the present disclosure relates to a method of manufacturing a power electronic module 10 as previously described.

[0090] The process includes the following steps: - obtaining box 4 as previously described, - the injection of the encapsulation material 5 into the interior volume 41 of the housing 4 through said at least one injection orifice 44, - vacuum degassing of the encapsulation material 5 from the interior volume 41 of the housing 4 and through the at least one degassing orifice 45.

[0091] The method may comprise a step of mounting the sealing film 50 on the housing 4 so as to cover said at least one injection orifice 44 and said at least one degassing orifice 45.

Claims

Claims

1. Power electronic module (10) for electric motor (1), the power electronic module (10) comprising: - at least one electronic component (2), - a housing (4) delimiting an interior volume (41) housing said at least one electronic component (2), - an encapsulation material (5) at least partially filling the interior volume (41) of the housing (4), in which the housing (4) comprises at least one injection orifice (44) for the encapsulation material (5) and at least one degassing orifice (45) configured to allow degassing of the encapsulation material (5) from the interior volume (41) to the outside of the housing (4), and in which the housing (4) is made in one piece.

2. Electronic power module (10) according to claim 1, wherein the housing (4) comprises an upper wall (42) facing said at least one electronic component (2) and side walls (43) extending from the upper wall (42) at the periphery of the latter, the upper wall (42) and the side walls (43) delimiting said interior volume (41), said at least one injection orifice (44) and said at least one degassing orifice (45) passing through the upper wall (42) of the housing (4).

3. Power electronic module (10) according to claim 1 or 2, wherein said at least one injection port (44) comprises a single injection port (44) or several injection ports (44).

4. Power electronic module (10) according to claim 3 combined with claim 2, in which the single injection orifice (44) has a substantially central position relative to the upper wall (42) of the housing (4).

5. Power electronic module (10) according to one of the preceding claims combined with claim 2, wherein said at least one injection orifice (44) has a surface area (Si) less than the largest dimension of the smallest debris envisaged.

6. Power electronic module (10) according to one of the preceding claims combined with claim 2, comprising a plurality of degassing orifices (45) distributed symmetrically with respect to an axis (Y1, Y2) of a plane of the upper wall (42) of the housing (4).

7. Power electronic module (10) according to one of the preceding claims, in which said at least one degassing orifice (45) has a surface area (Sd) less than the largest dimension of the smallest debris envisaged.

8. Power electronic module (10) according to one of the preceding claims, comprising a sealing film (50) covering said at least one injection orifice (44) and said at least one degassing orifice (45).

9. Power electronic module (10) according to the preceding claim, wherein the sealing film (50) is positioned on the housing (4) or is intrinsically configured so as to lead to the formation of a rupture zone at a predetermined location.

10. Electric motor (1) comprising at least one electronic power module (10) according to one of the preceding claims.

11. Electric motor (1) according to the preceding claim, comprising a plurality of such electronic power modules (10) arranged circularly around an axis of rotation (X) of the electric motor (1).

12. A method of manufacturing a power electronic module (10) according to one of claims 1 to 9, the method comprising the following steps: - obtaining the box (4), - injecting the encapsulating material (5) into the interior volume (41) of the housing (4) through said at least one injection orifice (44), - vacuum degassing of the encapsulating material (5) from the interior volume (41) of the housing (4) and through the at least one degassing orifice (45).

Images