INVERTER SYSTEM FOR A MOTOR VEHICLE'S DRIVETRAIN

Description

[0001] The invention relates to improvements for an inverter system for a drive train of a motor vehicle.

[0002] An inverter system or converter device is arranged between a battery and an electric motor, allowing the energy stored in the battery to be supplied to the motor via the inverter system. The inverter system can comprise individual subunits, such as current converters, power semiconductors, intermediate circuit capacitors, drive units (GDUs), and a control board, which are preferably housed in a single housing.

[0003] To ensure the functional reliability of an inverter system, different environmental conditions are required for the individual subunits. In particular, the high heat dissipation of power semiconductors requires a cooling structure. Appropriate cooling technologies or cooling structures for inverter systems or converter units are known from the StdT.

[0004] The power converter unit described in JP 2015-130735 comprises a housing unit divided into a first housing section and a second housing section. The first housing section accommodates a first power converter and a first cooling device, which are integrated into a single unit. The second housing section serves as a second cooling device, and a second power converter is arranged inside the second housing section.

[0005] Another design for a power converter unit is known from DE 10 2017 127 383 A1. Two cooling units are arranged in the housing of the power converter unit, connected via a cooling medium channel. The subunits are arranged on one of the cooling surfaces of the cooling units according to their heat generation.

[0006] In addition to cooling, an inverter system faces the problem of EMC interference between subunits if they are arranged in a housing or if the shielding is insufficient. The StdT recommends implementing shielding using shielding plates or other additional measures such as shielded cables, shield pads, and ground connections, etc.

[0007] From US 2003 / 067 748 A1 an inverter system for a motor vehicle is known which is arranged in a multi-part housing, wherein several electronic levels arranged one above the other are provided and the interior of the housing has several zones.

[0008] An object of the present invention is to propose an inverter system in a housing with which improved functionality and operational reliability of the inverter system can be achieved.

[0009] The object is achieved according to the invention by an embodiment according to independent claim 1. Further advantageous embodiments of the present invention can be found in the subclaims.

[0010] An inverter system for a drive train of a motor vehicle is proposed, which is arranged in a multi-part housing, comprising a control board which can be connected to control lines via control cable connections, intermediate circuit capacitors, power semiconductors, control units (GDU), current transformers and a connection area for DC input and inverter output.

[0011] According to the invention, the housing comprises an electronics level, a power level, and a connection level arranged one above the other, with the interior of the housing having several zones in which different conditions prevail with regard to temperature and / or EMC shielding. According to the invention, a zone is understood to be an area or spatial region in which specific environmental conditions are specifically created. For example, specific temperature conditions are specifically created for a subunit, or the desired shielding is ensured from an EVM perspective.

[0012] According to the invention, the housing is further divided into a first space and a second space by a partition wall, wherein the power level and the control level are arranged in the first space, which in turn is divided into several zones, and the connection level is arranged in the second space and forms a zone.

[0013] The separation of the rooms is designed in such a way that, in particular, no targeted air exchange can take place.

[0014] According to the invention, the power level and the control level located below it are separated by a heat sink in the first compartment. Unlike the partition wall, however, the heat sink is not designed to completely separate the levels.

[0015] According to the invention, the power level and the control level each have two zones, with one zone per level adjacent to a first cooling zone of the heat sink, and one zone per level adjacent to a second cooling zone of the heat sink. The heat sink zones each have a top and bottom side, each of which is adjacent to a zone.

[0016] In a preferred embodiment, the power semiconductors in the power level are mounted on the heat sink in the first cooling zone, and the intermediate circuit capacitors are mounted in the second cooling zone. Within the meaning of the invention, "mounted" means simultaneously connected in a thermally conductive manner.

[0017] Furthermore, according to the invention, the control board is arranged in a recess of the heat sink in the area of ​​the second cooling zone. The shape of the recess, as well as the material of the heat sink (aluminum), and the selected wall thickness, achieve particularly good EMC shielding, eliminating the need for additional shielding elements.

[0018] The current transformers and the control units (GDUs) are connected to the control board via connecting cables. The connecting cables run through a zone located essentially beneath the heat sink. Furthermore, the connecting cables run as far as possible past the heat sink through the power level to the connection level, thus shielding them from interference (EMC) over the essential length.

[0019] The coupling of the power semiconductors with the intermediate circuit capacitors is achieved by means of busbars, whereby the busbar connection comprises means that enable thermal decoupling of power semiconductors and intermediate circuit capacitors or reduce the input of heat from the power semiconductors into the intermediate circuit capacitors.

[0020] These means may be an electrically insulating thermally conductive element with which thermal energy can be dissipated from the busbars to the upper part of the housing.

[0021] The enclosed figures show a possible embodiment in detail. They show: Fig. 1 Inverter system in section Fig. 2 Zone division Fig. 3 Sketch of heat sink with control board Fig. 4 Inverter system in the drive train

[0022] Figure 1shows an inverter system 1 in section, so that all essential subunits, such as the current transformers 5, the control units (GDU) 31, the power semiconductors 4, the intermediate circuit capacitors 3 and the control board 2 can be seen.

[0023] Figure 2 shows in a sketch the essential structure of the housing with the individual zones 23 a to e in which the inverter system 1 is housed.

[0024] The housing, composed of the lower housing section 9, the upper housing section 10, the housing base 11, and the housing cover 12, has three levels 6, 7, and 8 and five main zones 23 ae within the housing, with the housing being sealed from the environment. Levels 6 and 7, i.e., the electronics level 6 and the power level 7, form a first space 21 a. The heat sink 13 is arranged between levels 6 and 7, and a passage area 22 for the control power cables 17 is provided.

[0025] The third level 8, the connection level 8, is a separate compartment 21b, zone 23a, within the housing. The compartment 21b, which forms zone 23a, is separated from compartment 21a by the partition 24 in the upper housing section 10. The necessary control power cables 17 from the current transformer 5 to the control board 2 and the busbars between the current transformer 5 and the power semiconductors 4 are routed through the partition 24, with sealing elements provided at the through-openings, thus separating compartments 21a and b.

[0026] The individual zones 23 a to e have different functions that are essential for the functionality of inverter system 1. Connection area 8, zone 23 a, is a closed area that is easily accessible by removing the housing cover, allowing for easy connection and disconnection of the vehicle-side power wiring for installation or repair. Furthermore, verification of the absence of voltage in the intermediate circuit can be performed with the housing cover 12 open.

[0027] The partition wall 14 not only provides a spatial separation, but also a thermal and EMC-compliant separation from the power level 7, so that the current transformer 5 and the associated DC contactor are thermally decoupled from the power level 7 and EMC shielding is ensured.

[0028] Room 21a is located below the connection level. As can be seen from the Figure 1 and 2As can be seen, this space comprises the power area 7 and the electronics area 6, with the space 21a being divided into the four zones 23b to e. In zone 23b, the power semiconductors 4 are positioned on the heat sink 13 so that the waste heat from the power semiconductors 4 can be efficiently dissipated. On the power level 7, in addition to the power semiconductors 4, the intermediate circuit capacitors 3 are attached in zone 23c to the heat sink 13, which in this zone area is essentially formed by the supply and discharge channels 26a, b and a connecting web 27.

[0029] The power semiconductors 4 and the intermediate circuit capacitors 3 are connected for power via short busbars 16, which are located in two different thermal zones 23b and 23c. A thermal zone is an area in which defined temperature conditions prevail that differ from other zones or areas.

[0030] The heat sink 13 serves as the support or mounting plane for the power semiconductors 4 and the intermediate circuit capacitors 3. To achieve the different thermal conditions, the cooling channel layout is selected such that the cooling channels run only in the area of ​​the power semiconductors, and the intermediate circuit capacitors 3 are mounted on the web 27 between the supply and discharge channels 26a, b. The heat sink 13 thus has two cooling zones 29a, b.

[0031] For further thermal separation of power semiconductors 4 and intermediate circuit capacitors 3, a thermal interruption is provided which prevents excessive heat input via the busbars 16 from the power semiconductors 4 to the intermediate circuit capacitors 3. For this purpose, heat-conducting but electrically insulating connections, so-called thermocouples or thermal pads 15, are provided between the busbars 16 and the upper housing part 10, which transfer or dissipate at least part of the thermal energy transmitted via the busbars 16 to the housing as a heat sink.

[0032] The control board 2 is arranged in the further zone 23 d. For the control board 2, it is important that the space or zone 23 d is shielded against high temperatures and against electromagnetic waves, EMC. Zone 23 d is located below the intermediate circuit capacitors 3. In this area, the web 27 of the heat sink 13 is enclosed in a U-shape by the cooling channel in the heat sink 13. Since the web 27 is relatively thin compared to the cooling channel area, a recess 28 is created under which the control board 2 is positioned. The recess shape, the associated enveloping cubature of the heat sink, and the fastening of the control board 2 in the recess 28 can thus be effectively used for EMC shielding, particularly because the housing 9 with the heat sink 13 is made of an aluminum alloy.

[0033] Another zone 23 e is an area within the housing through which the control current cables 17 are routed. The control current cables 17 connect the current transformers 5 and the control units (GDU) 31 to the control board 2 and are routed along the housing wall of the power level 7 and below the heat sink 13 in the electronics level. Below the heat sink 13, the control current cables 17 are separated from the power semiconductor area, zone 23 b, so no additional shield connections are required, and the control current cables 17 of the control units (GDU) 31 do not need to be additionally shielded.

[0034] Figure 3 shows a sketch of the housing base 9 with the heat sink 13 and the control board 2 attached to it. The recess 28 between the supply and discharge channel 26 a, b and the web 27 located therebetween, to which the control board 2 is attached, can be seen.

[0035] Further in Figure 4The inverter system 1 is shown in the drive train. This illustration serves to facilitate general understanding and clearly shows the separation of the connection levels, such as the power level 8, to which the high-voltage cables 30 are connected, and the electronics level 6, with the control cable connections 18, which are connected to the data bus cables. List of reference symbols

[0036] 1 Inverter system 2 Control board 3 Intermediate link capacitor 4 Power semiconductor 5 Current transformer 6 Electronics level 7 Power level 8 Connection level 9 Housing base 10 Housing top 11 Housing base 12 Housing cover 13 Heat sink 14 Partition wall 15 Thermocouple 16 Busbars 17 Control current cable 18 Control cable connection 19 Coolant connection 20 Cooling channel 21 a- b Room 22 Passage area 23 a-e Zones 24 Motor 25 Sealing element 26 a, b Supply and discharge channel 27 Web 28 Trough 29 a, b Cooling zones 30 High-voltage cable 31 Control unit (GDU)

Claims

1. Inverter system (1) for a drive train of a motor vehicle, which is arranged in a multipart housing (9, 10, 11, 12), comprising a control board (2) which is connectable by means of control cable terminals (18) and control lines, intermediate circuit capacitors (3), power semiconductors (4), actuation units (31) and power converters (5), wherein the housing comprises an electronics level (6), a power level (7) and a connection level (8), arranged one above another, wherein the interior of the housing (9, 10, 11, 12) comprises a plurality of zones (23 a - e) in which different conditions prevail, with respect to temperature and EMC shielding; characterized in that the housing (9, 10, 11, 12) is moreover divided by means of a dividing wall (14) into a first volume (21 a) and a second volume (21 b), wherein the power level (7) and the control level (6) are arranged in the first volume (21 a) which, in turn, is subdivided into a plurality of zones (23 b - e), and the connection level (8) is arranged in the second volume (21 b), and forms a zone (23 a); in the first volume (21 a), the power level (7), and the control level (6) which is arranged thereunder, are separated by a heat sink (13); the power level (7) and the control level (6) respectively comprise two zones (23 b, c and 23 d, e), wherein the zones (23 b and 23 e) adjoin a first cooling zone (29 a) of the heat sink (13), and the zones (23 b and 23 d) adjoin a second cooling zone (29 b) of the heat sink (13); in the power level (7), the power semiconductors (4) are fastened in the region of the first cooling zone (29 a), and the intermediate circuit capacitors (3) are fastened to the heat sink (13) in the region of the second cooling zone (29 b); the control board (2) is arranged in the region of the second cooling zone (29 b), in a depression (28) of the heat sink (13).

2. Inverter system (1) according to Claim 1, characterized in that the power converters (5) and the control board (2) are coupled by means of connecting cables (17), wherein the connecting cables (17) are routed through a zone (23 e) which is essentially arranged below the heat sink (13).

3. Inverter system (1) according to Claim 1, characterized in that the power semiconductors (4) and the intermediate circuit capacitors (3) are coupled by means of conductor rails (16), wherein the conductor rail connection comprises means (15) which permit a thermal decoupling of the power semiconductors (4) and intermediate circuit capacitors (3) .

4. Inverter system (1) according to Claim 3, characterized in that the means (15) comprise an electrically insulating thermoelement, by means of which thermal energy can be diverted from the conductor rails (16) to the upper housing part (10).