KR102276784B1 - Inverter device and motor vehicle with such an inverter device - Google Patents

Abstract

The present invention relates in particular to an inverter device (8) for an electric machine (6) of a motor vehicle (2), wherein a plurality of plate-shaped semiconductor modules (10), in particular SiC, arranged overlapping in the direction of a common plate normal (N) a semiconductor module, each semiconductor module 10 coupled with a heat-conducting element 12 for cooling on both sides with respect to the direction of the plate normal N, the heat-conducting element 12 being air cooled or air cooled It is connected to a coolable heat sink (16). The invention also relates to a motor vehicle (2) comprising such an inverter device (8).

Description

INVERTER DEVICE AND MOTOR VEHICLE WITH SUCH AN INVERTER DEVICE

The present invention relates to an inverter device comprising a plurality of semiconductor modules and comprising a heat-conducting element, in particular for an electric machine of a motor vehicle. The invention also relates to a motor vehicle comprising such an inverter device.

An electrically powered vehicle generally includes a battery (a traction battery) that supplies energy to an electric machine for driving the vehicle. Herein, the term "electrically driven vehicle" means, in particular, an electric vehicle (BEV) that stores energy required for driving only in a battery, a range extended electric vehicle (REEV), and a hybrid vehicle (HEV) ( hybrid electric vehicle) and/or plug-in hybrid electric vehicle (PHEV).

Here, for the operation of the electric machine, an inverter is used which converts the DC voltage provided by the battery into an AC voltage. In general, such an inverter is formed by a (silicon semiconductor) Si semiconductor. The heat released during inverter operation must in this case be removed (dissipated) so as not to exceed the relatively low upper limit of the operating temperature range of the Si semiconductor (the so-called junction temperature). In particular, for this purpose, liquid cooling, in particular a water-ethylene glycol circuit, is used, since air cooling has a relatively small cooling capacity due to the low thermal conductivity of air. The liquid cooling system comprises in particular a pump, a heat exchanger, a hose for the liquid and the liquid itself, so this cooling disadvantageously has a relatively large weight and requires a relatively large installation space.

See, for example, IEEE Transactions on power electronics, Vol. 29, No. 5, May 5, 2014, B. In "Design and Analysis of 55-kW Air-Cooled Automotive Traction Driven Inverter" by B. Wrzecionko et al., SiC-JFETs (silicon carbide junction gate field-effect transistors) An inverter system formed is disclosed.

Such SiC semiconductors (silicon carbide semiconductors) advantageously have higher junction temperatures and lower power dissipation than Si semiconductors. As a result, air cooling of such a SiC semiconductor or SiC semiconductor module becomes possible.

Also known are devices for cooling electronic components, for example from DE 10 2012 021 445 A1. Here, the electronic component is disposed in the receiving device. Their housing is provided with an air line arranged downstream of the evaporator of the automobile air conditioner. In order to cool the electronic components, in the air line, an air stream cooled by an automobile air conditioner may flow.

It is an object of the present invention to provide a suitable inverter device. In particular, the cooling here should be in a way that saves as much structural space, weight and/or cost as possible. In addition, an automobile including such an inverter device should be provided.

With regard to an inverter device, this object is achieved according to the invention by the features of claim 1 of the present application. In the context of motor vehicles, this object is achieved according to the invention by the features of claim 8 of the present application. Advantageous embodiments and developments are the subject of the dependent claims. The description here relating to the inverter device applies similarly also to automobiles and vice versa.

An inverter device is provided and installed in particular for an electric machine of a motor vehicle. The inverter device includes a plurality of plate-type semiconductor modules, preferably SiC semiconductor modules (silicon carbide semiconductor modules) that are stacked and overlapped in the direction of a common plate normal. Accordingly, the semiconductor modules are arranged parallel to each other. An inverter is formed by the semiconductor module.

Here, a plate-like object includes an extension in a space direction, and this extension in a space direction should be understood to mean that it is relatively small compared to an extension in a plane oriented perpendicular to this space direction. This spatial direction forms the direction of the plate normal to the plate-like semiconductor module. In this case, the surface of the semiconductor module oriented perpendicular to the plate normal is referred to here and below as the broad side. The side adjacent to the broad side is referred to as the end face.

Each semiconductor module is also coupled with a heat-conducting element for cooling on both sides with respect to the direction of the plate normal. Accordingly, each semiconductor module has a heat-conducting element arranged side by side on its wide surface and is in thermally conductive contact with the heat-conducting element.

Suitably, a single heat-conducting element is each arranged between the two semiconductor modules. In summary, in this case a heat-conducting element is respectively arranged between each semiconductor module and outside of the two outermost semiconductor modules with respect to the direction of the plate normal. Accordingly, the semiconductor module is disposed between each heat-conducting element.

The heat-conducting element is also connected in particular to a separate air-cooled or air-coolable heat sink (thermal thermally conductive). Alternatively, each heat-conducting element is coupled to a respective heat sink. In summary, the heat emitted by the semiconductor module is dissipated by the heat-conducting element to a heat sink, which in turn is cooled by air or air flow. The heat sink preferably comprises as large a surface area as possible for improved heat transfer to the air. To this end, the heat sink for example comprises a plurality of lamellae which are oriented parallel to the flow direction of the air flow.

Advantageously, the (top) surface area used for heat dissipation is relatively large, due to the fact that the heat-conducting elements are arranged on both sides on each semiconductor module. As a result, relatively good heat diffusion and relatively good cooling of the semiconductor module are realized. When implementing the semiconductor module as a SiC semiconductor module, due to the relatively high junction temperature and relatively low power loss of the SiC semiconductor, even in the case of relatively high power of an electric machine and accompanying heat transfer of the SiC semiconductor module of the inverter device, cooling This becomes possible. Liquid cooling, especially water cooling, is not required, saving cost, structural space and weight.

Preferably, SiC semiconductor modules are used as semiconductor modules due to their relatively high junction temperature and relatively low power dissipation. Alternatively, such a semiconductor material having a high junction temperature and/or low power dissipation so as not to exceed the junction temperature by air cooling as described above during operation of the inverter device is suitable.

Particularly suitable for this purpose is a semiconductor material having a junction temperature corresponding to the junction temperature of the SiC semiconductor or higher and a dissipation power corresponding to less than or equal to that of the SiC semiconductor. For this purpose, for example, a GaN semiconductor or a GaN semiconductor module (gallium nitride semiconductor module) may be used. Since SiC semiconductor modules are preferably used, hereinafter only SiC semiconductor modules are mentioned, but the description also applies to semiconductor modules having corresponding characteristics.

Preferably only the heat sink acts on the air flow. Thus, since the SiC semiconductor module is not cooled by the corresponding air stream, the SiC semiconductor module is not damaged by the air stream and/or optionally by (dust) particles present in the air stream.

The SiC semiconductor module includes a plurality of semiconductor switches, for example, enhancement type junction gate field-effect transistors (JFETs) or metal-oxide-semiconductor field-effect-transistors (MOSFETs), whereby an inverter is formed In a suitable embodiment, the inverter device comprises three SiC semiconductor modules, wherein a half bridge of the inverter is formed in each case by each SiC semiconductor module.

According to a suitable embodiment, each heat-conducting element is connected to the heat sink by means of a heat pipe. Alternatively, each heat-conducting element is connected to the heat sink by a plurality of heat pipes. Preferably, the heat pipe projects at least partially into the heat-conducting element. For example, a heat pipe is embedded in a heat-conducting element.

Additionally, for example, the heat pipe is in direct thermal contact with the respective SiC semiconductor module. The heat-conducting element in this case additionally fulfills the purpose of a spacer and of a heat storage. The heat-conducting element is preferably formed of a material having a relatively good thermal conductivity, in particular copper.

Alternatively, each heat-conducting element is formed by a heat pipe, wherein the heat-conducting element formed as a heat pipe is connected to a heat sink. In particular, in this way, the heat pipe is in direct thermal contact with the respective SiC semiconductor module.

According to an advantageous development, the inverter device comprises (first) a control unit with a printed circuit board. The first printed circuit board is in particular a so-called driver board. Preferably, the first printed circuit board extends parallel to the plate normal and is arranged on, preferably parallel to, the first end face of the SiC semiconductor module. The SiC semiconductor module is in this case electrically connected to the first printed circuit board. In this case, the contact point of the SiC semiconductor module to the first printed circuit board is disposed on the first end face.

Preferably in this case the so-called gate driver or control input driver of the first printed circuit board for each SiC semiconductor module can and preferably also be formed in terms of inductance identically. Consequently, the switching times of the semiconductor switches of the corresponding SIC semiconductor modules are the same. More advantageously, the printed circuit board is arranged in a space-saving manner.

Preferably, each (AC) phase terminal of the inverter is likewise disposed on a first end face of a corresponding SiC semiconductor module. The phase terminals are arranged in this case, for example, between the contacts to the first printed circuit board. In particular the phase terminals are guided through corresponding recesses in the first printed circuit board.

Preferably, the first printed circuit board is spaced apart from the first end face of the SiC semiconductor module, so that heating of the first printed circuit board due to heat transferred during operation of the SiC semiconductor module is prevented or only a small heating this is done

According to a suitable embodiment, the control unit comprises in particular a second printed circuit board forming a controllerboard. It extends in a space-saving manner perpendicular to the direction of the plate normal and is arranged next to one of the outermost heat-conducting elements in this direction. Preferably, the second printed circuit board is likewise arranged spaced apart from the outermost heat-conducting element in order to prevent or at least reduce heat transfer from the outermost SiC semiconductor module.

Alternatively, the second printed circuit board is disposed parallel to the first printed circuit board. Suitably, wherein the first printed circuit board is disposed between the second printed circuit board and the SiC semiconductor module. The second printed circuit board is arranged next to the first printed circuit board perpendicular to the plate normal in this direction.

According to a suitable development, the inverter device comprises a plurality of DC link capacitors. They are connected to the SiC semiconductor module and disposed on the second end face of the SiC semiconductor module. Preferably the DC link capacitor is disposed on the (second) end face of the SiC semiconductor module comprising the contact to the DC link capacitor. Suitably, the contact to the DC link capacitor is arranged on an end face parallel (opposite) to the first end face in this case. Alternatively, for example, a DC link capacitor is mounted on a common board. Preferably, the board is space-saving in this case arranged parallel to the second end face of the SiC semiconductor module and thus parallel to the plate normal. As the DC link capacitor, preferably a ceramic capacitor suitable for high temperature is used.

According to an advantageous development, the inverter device comprises a fan. This fan is responsible for creating an air stream that cools the heat sink. The fan is provided to be arranged in this case on the heat sink or in the air duct in which the heat sink is housed.

According to an advantageous development, the motor vehicle comprises an inverter device of one of the variants described above. In particular, the inverter device includes a plurality of plate-shaped SiC semiconductor modules arranged overlapping in the direction of the common plate normal, wherein each of the SiC semiconductor modules is coupled with a heat-conducting element for cooling on both sides with respect to the direction of the plate normal.

The motor vehicle according to an advantageous development comprises an air conditioner. Thereby, the air flow for cooling the heat sink may be pre-conditioned, ie cooled, filtered and/or dehumidified. Alternatively or additionally, the air conditioning system may be supplied with an air stream heated by a heat sink. This heated air stream is used in particular for heating the vehicle interior space.

When the heated air stream is not used to heat the interior space of the vehicle, it is discharged to the surrounding environment through an air outlet. When the air flow heated by the heat sink is used to heat the interior space of the vehicle, the heating power of the air conditioner is reduced accordingly, and consequently, energy-efficient operation of the vehicle is realized.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

1 schematically shows an automobile including an inverter device and an air conditioner, wherein a heat sink of the inverter device is accommodated in an air duct of the air conditioner.
2 shows a perspective view of an inverter device comprising a plurality of heat-conducting elements each having a SiC semiconductor module disposed therebetween, wherein each heat-conducting element is connected to a heat sink by a heat pipe.
Fig. 3 shows an inverter device in a schematic front view of a first end face of a SiC semiconductor module;
Fig. 4 shows the inverter device in a schematic side view of an end face of the SiC semiconductor module adjacent to the first end face;

Parts and sizes corresponding to each other are always provided with the same reference numbers in all drawings.

1 shows an electrically driven motor vehicle 2 . For this purpose, the motor vehicle 2 comprises an electric machine designed as a (traction) battery 4 and an electric motor 6 . An inverter device 8 is connected between the battery 4 and the electric motor 6 , by which the DC voltage provided by the battery 4 or the DC current provided by the battery 4 is electrically It is converted into an AC voltage or AC current suitable for the operation of the motor 6 .

2 to 4 the inverter device 8 is shown in more detail. As can be seen here, the inverter device 8 comprises three SiC semiconductor modules 10 , wherein a half bridge of the inverter device 8 is respectively formed by each SiC semiconductor module 10 . is formed The SiC semiconductor module 10 thus forms an inverter. The SiC semiconductor module 10 is plate-shaped and covers a greater extent in one plane than in a direction perpendicular to this plane. The normal to this plane may be referred to as the plate normal (N).

The SiC semiconductor modules 10 are arranged parallel to each other. Therefore, SiC semiconductor modules include a common plate normal (N). In the direction of the plate normal (N), the SiC semiconductor modules 10 are superimposed and stacked. The SiC semiconductor module 10 is aligned in this direction.

The inverter device 8 also comprises a plurality of heat-conducting elements 12 . They are arranged between the SiC semiconductor modules 10 and outside of the two external SiC semiconductor modules 10 with respect to the plate normal N. In this way, in each SiC semiconductor module 10 one of the heat-conducting elements 12 is arranged parallel to the direction of the plate normal N. The SiC semiconductor module 10 is thermally conductively coupled to each heat-conducting element 12 in a manner not shown further for cooling, ie for the removal of heat generated during operation.

Each heat-conducting element 12 is also connected to a heat sink 16 by a heat pipe 14 . In summary, heat transfer or heat dissipation takes place from the SiC semiconductor module 10 through the heat conducting element 12 and the heat pipe 14 to the heat sink 16 . The heat sink 16 includes a lamellar structure, so that heat transfer to _{the air stream L K acting on it to cool is improved.} A fan 18 is disposed on the heat sink 16 to generate an air flow L _{K .}

Each of the SiC semiconductor modules 10 includes a plurality of contact points 22 on a first end face 20 disposed parallel to the direction of the plate normal N. The first end face 20 of the SiC semiconductor module 10 is arranged here in a common plane. The contact 22 serves to electrically connect each SiC semiconductor module 10 and the first printed circuit board 24 of the control unit 26 of the inverter device 8 . The first printed circuit board 24 is shown in this case transparent for better clarity in FIG. 2 . Accordingly, the SiC semiconductor module 10 is electrically connected to the first printed circuit board 24 . Here, the first printed circuit board 24 is formed as a driver board. The first printed circuit board 24 here likewise extends parallel to the plate normal N and parallel to the first end face 20 of the SiC semiconductor module 10 . Further, since the first printed circuit board 24 is disposed spaced apart from the first end face 20 , heat transfer from the SiC semiconductor module denoted 10 to the first printed circuit board 24 is avoided or at least reduced. do.

As can be appreciated in particular in FIG. 4 , the control unit 26 also comprises a second printed circuit board 28 , which is designed as a Controllerboard, this second printed circuit board comprising a first printed circuit board. (24) is electrically connected. The second printed circuit board 28 in this case extends in a plane perpendicular to the direction of the plate normal N, wherein the second printed circuit board 28 is in this direction one of the outermost heat-conducting elements 12 . placed next to and at a distance from it in a space-saving manner.

According to an alternative not further shown, the second printed circuit board 28 is arranged parallel to the first printed circuit board 24 . In this case, the first printed circuit board 24 is disposed between the second printed circuit board 28 and the SiC semiconductor module 10 .

For better clarity, the fan 18 is not shown in FIGS. 3 and 4 and the first printed circuit board 24 is not shown in FIG. 3 .

The inverter device 8 also includes three DC link capacitors 30 . They are electrically connected to the contacts 22 of the SiC semiconductor module 10 and are disposed on the second end face 32 . The second end face 32 of the SiC semiconductor module 10 is here oriented parallel to their first end face 20 , in other words the second end face 32 is the first end face 20 . is leaning towards The DC link capacitor 30 here extends in a plane perpendicular to the plate normal N.

According to an alternative not further shown, the DC link capacitor 30 may be mounted on a common board. This board here extends parallel to the second end face 32 of the SiC semiconductor module 10 , and thus parallel to the plate normal N .

A heat pipe 14 is embedded into the heat-conducting element 12 , with respect to a third end face 34 of the SiC semiconductor module 10 adjacent to the first end face 20 and adjacent to the second end face 32 . It projects from the side of each parallel heat-conducting element 12 .

According to an alternative not further shown, each heat-conducting element 12 is formed by a heat pipe 14 , wherein the heat pipe 14 is connected to an air-cooled or air-coolable heat sink 16 . do. Thus, the heat pipe is in direct thermal contact with each SiC semiconductor module.

In summary, in this way a compact arrangement, ie a space-saving arrangement, of the control unit 26 , the DC link capacitor 30 and the heat pipe 14 is realized.

In FIG. 1 also an air conditioner 36 with an air duct 38 is shown schematically and simplified. In this case, the heat sink 16 is housed in the air duct 38 . In this way, the air stream L _K supplied to the heat sink 16 may be pre-conditioned by the air conditioner, ie may be pre-cooled, dehumidified and/or filtered. Additionally or alternatively, an air stream L _W heated by a heat sink 16 may be supplied to the air conditioner 36 . For example, the heated air stream L _W is used in an unillustrated manner by the air conditioner 36 to heat the vehicle interior space of the motor vehicle 2 .

The present invention is not limited to the embodiments described above. Rather, other modifications of the invention may also be derived therefrom by those skilled in the art without departing from the gist of the invention. In particular, all individual features described in connection with the exemplary embodiments may also be combined with each other in other ways and without departing from the gist of the present invention.

2 cars
4 battery
6 electric motor/electric machine
8 inverter unit
10 SiC semiconductor module
12 heat conduction element
14 heat pipe
16 heat sink
18 fans
20 first end face
22 contacts
24 first printed circuit board/driver board
26 control unit
28 2nd printed circuit board/control board
30 DC Link Capacitors
32 second end face
34 third end face
36 air conditioner
38 air duct
L _K pre-conditioned airflow
L _W Heated air flow
N plate normal

Claims (9)

An inverter device (8) comprising:
- A plurality of plate-type semiconductor modules 10 overlapping in the direction of the common plate normal (N)
including,
- each of the semiconductor modules 10 is coupled with a heat-conducting element 12 for cooling on both sides with respect to the direction of the plate normal N,
- said heat-conducting element 12 is connected to an air-cooled or air-coolable heat sink 16;
- the inverter device 8 comprises a control unit 26 , which extends parallel to the plate normal N and has a first end face 20 of the semiconductor module 10 . ) disposed on a first printed circuit board (24), the semiconductor module (10) having, on the first end face (20), a contact (22) for connecting to the first printed circuit board (24) ), including
- the inverter device (8) comprises three semiconductor modules (10), wherein a half bridge is formed by each of the semiconductor modules (10). The method of claim 1,
Each of the heat-conducting elements 12 is connected to the heat sink 16 by a heat pipe 14 , or each of the heat-conducting elements 12 is connected to a heat pipe 14 connected to the heat sink 16 . Inverter device, characterized in that formed by. The method of claim 1,
The control unit 26 includes a second printed circuit board 28 , wherein the second printed circuit board 28 extends perpendicularly to the direction of the plate normal N and is an outermost row in this direction. Inverter arrangement, characterized in that it is arranged next to one of the conductive elements (12), or that the second printed circuit board (28) extends parallel to the first printed circuit board (24). 3. The method according to claim 1 or 2,
A plurality of DC link capacitors 30 connected to the semiconductor module 10 and disposed on the second end face 32 of the semiconductor module 10 .
Inverter device comprising a. 3. The method according to claim 1 or 2,
A fan 18 disposed on the heat sink 16 or provided to be disposed within an air duct 38 in which the heat sink 16 is received.
Inverter device comprising a. A motor vehicle comprising an inverter device (8) according to claim 1 or 2. 7. The method of claim 6,
an air conditioner (36);
_{The air conditioner pre-conditions the air flow L K} for cooling the heat sink 16 by the air conditioner, or provides the air conditioner to the heat sink 16 . A vehicle, characterized in that the heated air flow (L _{W ) is supplied by the.} delete delete

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