Electrical device comprising a power semiconductor module and at least one capacitor

Abstract

The invention relates to an electrical device, comprising: a power semiconductor module (4); at least one capacitor (8); a circuit carrier (2) and a first heat sink (1). The power semiconductor module (4) and the circuit carrier (2) are arranged on the first heat sink (1), and the electrical device comprises a second heat sink (5) arranged on the power semiconductor module (4) and connected to the first heat sink (1).

Description

Technical Field

[0001] The present invention relates to an electrical device, comprising:

[0002] - Power semiconductor modules;

[0003] - at least one capacitor;

[0004] - a circuit carrier, and

[0005] - a first heat sink,

[0006] In this case, the power semiconductor module and the circuit carrier are arranged on a first heat sink. Background Art

[0007] Various electrical devices with semiconductor power modules of the aforementioned type are known in the prior art. In one of these electrical devices, capacitors and various other power components (e.g. chokes) are arranged on a circuit carrier adjacent to the power module. The remaining area of ​​the circuit carrier can be used to arrange other components, which are necessary, for example, for the control of the power semiconductor module. The power semiconductor module is connected to the conductors and components on the circuit carrier.

[0008] Such electrical devices are also used in motor vehicles. The circuit arrangement used in motor vehicles generally requires that the electrical equipment be compact and occupy little installation space. Summary of the invention

[0009] Another problem with electrical devices having power stages is that heat is generated in the power stages, for example in power semiconductor modules, and this heat must be dissipated in order to prevent damage to the power semiconductor modules. In compact electrical devices with densely packed components, heat dissipation is more difficult than in circuit arrangements with more distant components, since the latter generally have a larger area to dissipate heat to the environment by convection or radiation. The present invention is therefore based on the task of improving the heat dissipation of electrical devices of the type mentioned above.

[0010] The object is achieved by the fact that the electrical device has a second heat sink arranged on the power semiconductor module and connected to the first heat sink. The second heat sink improves the heat transfer from the power semiconductor module: not only the first heat sink on which the power semiconductor module is mounted can be used for heat transfer, but also the second heat sink mounted on the power semiconductor module can be used for heat transfer. For example, by connecting the second heat sink, which is preferably much smaller than the first heat sink and therefore has only a fraction of the mass of the first heat sink, the heat transferred from the power semiconductor module to the second heat sink can be transferred to the first heat sink.

[0011] Another advantage of the second heat sink is that it can be used as a carrier for circuit arrangement elements of the electrical device, such as at least one capacitor. The at least one condenser can be arranged on the second heat sink. It is also possible that the at least one capacitor is arranged above the second heat sink, instead of being firmly connected to the second heat sink. The capacitor can have contact pins, in particular press-fit contacts, which pass through the recess in the second heat sink and are connected to the power semiconductor module. The power semiconductor module can have a socket or a receptacle in which the contact pins are electrically contacted and fastened.

[0012] If the capacitor is mounted on or above the second heat sink, a compact design of the electrical device is possible.

[0013] The second heat sink can be connected to the power semiconductor module by screws or other connecting means. The second heat sink can also be connected to the first heat sink by screws or other connecting means. Instead of using a connecting device, the connection can also be achieved by bonding. The heat transfer at the joint can be improved by using a thermally conductive paste.

[0014] The second heat sink may have at least one side wall, which may be substantially perpendicular to the first heat sink. The side wall may be connected to the power semiconductor module. This allows additional heat to be transferred from the power semiconductor module to the second heat sink.

[0015] The side wall may abut the first heat sink. The side wall may have a flange portion placed on the first heat sink. The flange portion increases heat transfer from the second heat sink to the first heat sink and promotes heat transfer.

[0016] The flange portion may be attached to the first heat sink.

[0017] The capacitor can preferably be a stack capacitor or a multilayer capacitor. The capacitor can especially be a plastic film capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Based on the accompanying drawings, the present invention will be explained in more detail below. As shown in the figure:

[0019] Figure 1 is a simplified top view of an electrical device according to the present invention,

[0020] Figure 2 is a simplified perspective view of the electrical device,

[0021] Figure 3 is a first simplified perspective exploded view of the electrical device, and

[0022] Figure 4 is a second simplified perspective exploded view of the electrical device. DETAILED DESCRIPTION

[0023] The simplified view of the electrical device of the invention in the attached drawing shows a first heat sink 1. The first heat sink 1 is an aluminum plate.

[0024] A circuit carrier, preferably a printed circuit board 2, is mounted on the first heat sink. The printed circuit board 2 contains printed conductors and various components that are not shown or not shown in full. The figure shows, for example, a choke 3. The circuit carrier almost completely covers one side of the heat sink. Only in one corner is there an exposed surface. A power semiconductor module 4 is arranged in this area, which is connected to the printed conductors and / or components on the printed circuit board 2 via contact pins.

[0025] The power semiconductor module 4 has a housing that accommodates several power semiconductor elements.

[0026] A second heat sink 5 is provided on the power semiconductor module 4 and on both sides of the power semiconductor module 4. The second heat sink comprises a plate 51 placed on the top side of the power semiconductor module 4. The two side walls 51 of the second heat sink 5 are attached to the outer wall of the power semiconductor module 4. Flanges 53 can be seen at the ends of the two side walls 51. The second heat sink 5 is firmly connected to the first heat sink 1 by screws 6, which are guided through the flanges 53. In addition, the second heat sink 5 is firmly connected to the power semiconductor module 4 with screws 7.

[0027] The capacitor 8 is arranged above the second heat sink 5. It is a capacitor module having several capacitors that can be connected to the power semiconductor module via contact pins 81. The contact pins 81 protrude through the recess in the plate 51 of the second heat sink 5 and are inserted into the jack or socket of the power semiconductor module 4. The contact pins 81 are electrically contacted and fixed in the jack or socket, whereby the capacitor 8 is integrally fastened.

[0028] Reference numerals list

[0029] 1 First heat sink

[0030] 2. Printed Circuit Board

[0031] 3 Choke

[0032] 4 Power semiconductor modules

[0033] 5 Second heat sink

[0034] 51 Board

[0035] 52 Sidewall

[0036] 53 Flange

[0037] 6 Screws

[0038] 7 Screws

[0039] 8 Capacitors

[0040] 81 Stylus

Claims

1. An electrical device having - a power semiconductor module (4), - at least one capacitor (8), - a circuit carrier (2), and - a first heat sink (1), The power semiconductor module (4) and the circuit carrier (2) are arranged on the first heat sink (1), It is characterized in that The electrical device comprises a second heat sink (5) arranged on the power semiconductor module (4) and connected to the first heat sink (1), wherein the at least one capacitor (8) is arranged on the second heat sink (5) but not between the first heat sink (1) and the second heat sink (5); Wherein, the second heat sink (5) has at least one side wall (52), and the at least one side wall (52) is placed on the first heat sink (1); The at least one capacitor (8) has a contact pin (81), which passes through a recessed portion of the second heat sink (5) and is connected to the power semiconductor module (4).

2. The electrical device according to claim 1, characterized in that The at least one side wall (52) is arranged substantially perpendicular to the first heat sink (1).

3. The electrical device according to claim 2, characterized in that: The at least one side wall (52) is in contact with the power semiconductor module (4).

4. The electrical device according to any one of claims 2 to 3, characterized in that: The at least one side wall (52) has a flange portion (53) placed on the first heat sink (1).

5. The electrical device according to claim 4, characterized in that: The flange portion (53) is attached to the first heat sink (1).

6. The electrical device according to any one of claims 1 to 3, characterized in that: The at least one capacitor (8) is a stacked capacitor or a laminated capacitor.

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