Circuit layout and motor vehicle

Abstract

Circuit arrangement (4) comprising at least three power electronics modules (11, 12, 13) and a cooling device (5) for cooling the power electronics modules (11, 12, 13), wherein the cooling device (5) comprises a coolant line (8) through which a coolant can flow and which can be operated in exactly one flow direction or in two flow directions, wherein the power electronics modules (11, 12, 13) are arranged along the coolant line (8) such that at least one power electronics module (11, 12, 13) dissipating a higher power loss than heat during operation of the circuit arrangement (4) is arranged upstream of at least one power electronics module (11, 12, 13) dissipating a lower power loss than heat with respect to each usable flow direction, wherein the power electronics modules (11, 12, 13) are half-bridges, each comprising two power transistors (15a - 15f),wherein the power transistors (15a - 15f) are each driven via a gate driver (22a - 22f), wherein at least three of the gate drivers (22a - 22f) have a common winding (23, 24) which provides a drive voltage for the at least three gate drivers (22a - 22f), wherein the circuit arrangement (4) comprises three identical power transistors (15a, 15c, 15e) connected to a high-voltage side and three identical power transistors (15b, 15d, 15f) connected to a ground side, wherein the gate drivers (22a, 22c, 22e) of the high-voltage-side power transistors (15a, 15c, 15e) each have a first winding (23) and the gate drivers (22b, 22d, 22f) of the ground-side power transistors (15b, 15d, 15f) each have a second winding (24), wherein the power transistors (15a - 15f) are connected such that one of the power electronics modules (11, 12, 13) each controls the high-voltage side power transistor (15a, 15c,15e) and the ground-side power transistor (15b, 15d, 15f) with the highest power dissipation, and another power electronics module (11, 12, 13) each comprising the high-voltage-side power transistor (15a, 15c, 15e) and the ground-side power transistor (15b, 15d, 15f) with the lowest power dissipation.

Description

The invention relates to a circuit arrangement comprising at least three power electronics modules and a cooling device for cooling the power electronics modules, wherein the cooling device comprises a coolant line through which a coolant can flow, which can be operated in exactly one flow direction or in two flow directions. The invention further relates to a method for producing a circuit arrangement and to a motor vehicle.Circuit arrangements with power electronics modules are used, for example, in motor vehicles with electric drives. There, they can be used as traction inverters for controlling three-phase electric machines. Due to the high power flow in such circuits, it may be necessary for at least individual components of the circuit arrangement to be cooled. Various methods for the temperature-dependent operation of circuit arrangements are known from the prior art.EP 2 562 896 A2 describes a control circuit for limiting a load current which flows through a controllable semiconductor component. The semiconductor component is controlled taking into account a measured and / or calculated load current-dependent power loss of the semiconductor component. Furthermore, a measured and / or calculated load current-dependent component temperature and / or a coolant temperature of the controllable semiconductor component can be taken into account for controlling the semiconductor component.DE 10 2009 005 372 A1 describes a temperature estimation controller which controls a torque command to an electric machine in such a way that overheating of one or more phases is prevented. The electric motor is actuated by an inverter comprising a plurality of power transistors, which inverter responds to the signals of a current-regulated torque controller in such a way that it supplies a voltage to each phase of the motor. The torque command may be decreased when the stator temperature of one or more phases is too high.DE 10 2013 017 089 A1 describes a method for regulating a coolant parameter of a coolant taking into account at least one signal representing an aging of an electronic assembly. In this case, converter-related parameters, the current clock frequency of the converter and transmission losses of the transistors and / or freewheeling diodes used can be detected and used together with the actual values of the cooling water temperature and of the cooling water volume flow as signals representing the aging of the electronic assembly.US 2013 / 0335920 A1 relates to a cooling device having element modules arranged at least partially in the coolant stream. For a power converter circuit, it is described that its semiconductor modules each comprising a transistor and a freewheeling diode are arranged as element modules in series in a cooling channel through which flow can take place in a flow direction. A coolant flows through the cooling channel via an inlet, which coolant leaves the cooling channel again at an outlet. The arrangement of the semiconductor modules is effected in such a way that the high-voltage and ground-side transistors or freewheeling diodes of a half bridge in each case follow one another in the channel.US 2016 / 0105084 A1 discloses a motor device having a motor unit, an inverter unit, a housing and a pump. By a coolant pumped through a cooling channel by means of the pump, the motor unit and the inverter unit can be cooled. In this case, it is provided that a power converter is first cooled upstream, then a capacitor and then the motor unit, since the power converter and the capacitor have elevated temperatures with respect to the motor unit.DE 11 2007 002 339 B4 discloses a vehicle drive device which has a motor generator, a power control unit and a housing. The power control unit includes a first inverter that drives the motor generator and a voltage converter that boosts a power supply voltage to apply the voltage to the first inverter. A choke coil of the voltage converter is arranged in such a way that it can release its heat to the housing. The arrangement of a boost converter and of two converters operated via the boost converter with respect to a cooling duct is also described, wherein the boost converter is positioned on an upstream side of the cooling water duct due to higher heat emission with respect to the converters. The arrangement of the converters in relation to the direction of flow also takes place in dependence on the amount of heat emitted by them.US 2004 / 0061138 A1 relates to a discrete semiconductor device, wherein a cooling channel is formed between a wall of a housing and a side wall of the semiconductor device. Thus, the semiconductor device can be surrounded at least for the most part by a coolant. In an inverter circuit with six semiconductor devices, these may be arranged in a matrix with two rows and three columns within the package. With respect to the flow direction of the cooling channel, the arrangement is such that the semiconductor component with the greatest waste heat is arranged at the beginning of the cooling channel and the further semiconductor components are arranged in descending order of their waste heat.DE 10 2014 219 846 A1 describes a cooling device for cooling power semiconductors, wherein the cooling device can be flowed through in two different flow directions.US 2012 / 0250385 A1 discloses a temperature detection apparatus having a temperature detection circuit that outputs a first pulse signal corresponding to a temperature detected by a temperature sensor, and an isolation transformer that transmits the first pulse signal to an integrated circuit that operates at an operating voltage different from the operating voltage of the temperature detection circuit. The isolation transformer is installed between the temperature sensing circuit and the integrated circuit. US 2009 / 0230938 A1 relates to an electric power conversion apparatus comprising a lower arm circuit which transmits control signals from a microcomputer via pulse transformers provided in an IC chip and outputs the control signal transmitted via the pulse transformer to a lower arm IGBT, a high voltage nMOS which converts the electric potential of the control signal transmitted via the other pulse transformer of the lower arm circuit for an upper arm IGBT, and an upper arm circuit which outputs the control signal whose electric potential has been converted by the high voltage nMOS to the upper arm IGBT.The invention is based on the object of specifying a circuit arrangement which is improved with respect to cooling.To achieve this object, in a circuit arrangement of the type mentioned at the beginning, the features of claim 1 are provided according to the invention.The advantage of such an arrangement of the power electronics modules is that the cooling of the power semiconductor modules is improved. In particular, it is thereby possible that, due to the arrangement of the power electronics modules, identical or as similar as possible operating temperatures of the power electronics modules can be achieved. Furthermore, the arrangement of the power electronics modules according to the invention allows the output power of the circuit arrangement to be increased with the same chip area of the power electronics modules, or the power semiconductor area required for the power electronics modules can be reduced with the same output power, which has an advantageous effect on the costs of producing the circuit arrangement.The power loss of the power electronics modules relates to the thermal power loss during operation of the power electronics modules or during operation of the circuit arrangement. In particular, the power loss can relate to the power loss occurring in at least one provided operating state of the power electronics modules or of the circuit arrangement. The provided operating state can be an operating state extending over a longer period of time and / or a continuous operating state, for example a current direction generated by the circuit arrangement, such as rectification, alternating direction or reversal. The power loss which is emitted on average over time during operation can be used, for example, as the power loss.The cooling device used for cooling the power electronics modules comprises a coolant line through which a coolant can flow. The cooling device can be operable in exactly one flow direction or in two flow devices. For operating the coolant device, the coolant device can comprise a conveying device or be connected to a conveying device, by means of which the coolant can be conveyed through the coolant line in one or in two, in particular opposite, flow directions. Two flow directions can be realized, for example, by switching over a conveying direction of the conveying device corresponding to the flow direction. The direction of flow indicates the direction in which the coolant flows through the coolant line. The power electronics modules of the circuit arrangement are in thermal contact with the cooling device, so that the heat generated by the power electronics modules as a power loss can be dissipated to the coolant flowing through the cooling device.Because a power electronics module which has a higher thermal power loss is arranged upstream of a power electronics module having a low power loss, with respect to the flow direction, the power electronics module having the higher power loss is first cooled by the coolant flowing through the coolant line of the cooling device. This results in particularly efficient cooling for this power electronics module, since the temperature of the coolant is initially the lowest. According to the invention, the power module arranged downstream with respect to the flow direction has a lower power loss than the power electronics module arranged upstream with respect to the flow direction, so that the rise in the temperature of the coolant for cooling the power electronics module arranged downstream with respect to the flow direction has no adverse effects.A power electronics module in the sense of the invention can comprise a plurality of power electronics components, wherein in this case the total thermal power loss of a part or all of the components of the power electronics module can be considered as a power loss of the power electronics module. The power loss can occur as thermal power loss, for example as switching losses and / or as forward losses of power electronic components.According to the invention, it can be provided that, in the case of exactly one flow direction, all power electronics modules are arranged along the coolant line in such a way that a power electronics module with a second, lower or identical power loss follows a power electronics module with a first power loss. This results in the advantage that the power electronics module with the highest power loss is in thermal contact with the coolant with the lowest coolant temperature, since it is first cooled. In the power electronics modules arranged subsequently, the coolant is heated on account of the heat dissipated by the respective power electronics modules arranged above. However, since the power loss of the respective power electronics modules along the flow direction likewise decreases, particularly efficient cooling is achieved overall for the entire circuit arrangement. In particular, it is possible in this way that, owing to the arrangement of the power electronics modules, identical or substantially identical operating temperatures of the power electronics modules can be achieved. In the case that two or more power electronics modules have the same power loss, these can be arranged one after the other along the flow direction in any desired sequence.According to the invention, it can be provided that, in the case of two flow directions, at least three power electronics modules are arranged along the coolant line in such a way that the power electronics module with the highest power loss is arranged at one of the at least one central position. In an odd number of power electronics modules, the center position denotes the position in the center of the arrangement of the power electronics modules along the coolant line. For example, in the case of three power electronics modules, the power electronics module with the highest power loss is arranged between the two other power electronics modules.In the case of an even number of power electronics modules, there are two central positions, each central position corresponding to a position of the pair of power electronics modules arranged in the middle of the arrangement of the power electronics modules. For example, in the case of four power electronics modules, the power electronics module with the highest power loss with respect to each of the flow directions is arranged as a second or third power electronics module.This arrangement results in advantageous cooling of all power electronics modules even in a cooling device which can be operated in two flow directions. By arranging the power electronics module with the highest power loss at a central position, it is advantageously avoided that the power electronics module with the highest power loss is arranged at the rear with respect to one of the flow directions.According to the invention, it is provided for the power electronics modules that they are half bridges, each of which comprises two power transistors, in particular power transistors embodied as insulated gate bipolar transistors (IGBTs) or as metal oxide semiconductor field effect transistors (MOSFETs). The power electronics modules can comprise further components, for example free-wheeling diodes or the like, in addition to the power transistors. It can be provided in particular that the circuit arrangement is a three-phase inverter which has three power electronics modules designed as half bridges.Furthermore, the invention provides that the power transistors are each driven via a gate driver, wherein at least three of the gate drivers have a common winding material which provides a driver voltage for the at least three gate drivers. It is possible for the gate driver to be a DC-to-DC converter or to comprise a DC-to-DC converter which is designed as a flyback converter (flyback converter). A logic signal used to drive the power transistors is subjected to amplification and / or level adaptation by the gate driver. Furthermore, a galvanic isolation between the low-voltage side, or LV side, and the high-voltage side, or HV side, of a network is achieved by the gate driver. It is possible for the supply of one or more gate drivers to take place from the LV side, wherein both the drive signal and the power supply of one or more gate drivers are conducted via the galvanic isolation. It is also possible for the supply of one or more gate drivers to take place from the HV side, wherein the high voltage of the HV side is converted into a low voltage. All gate drivers of the circuit arrangement may have the same type of supply or it may be provided that the gate drivers of the circuit arrangement have different types of supply.The gate drivers can comprise a winding material, which is embodied, for example, as a transformer and which converts a driver voltage representing the input voltage of the gate driver into the drive signal of the respectively assigned power transistor, in particular into a gate voltage of the transistor. The winding material can have a plurality of taps, so that at least two gate drivers can be connected to the same winding material. This contributes to a reduction in the number of components of the inverter, in particular on the primary side. It is of course also possible for each gate driver to comprise a separate item of winding material.According to the invention, it can be provided that the gate drivers generate a gate voltage of the power transistors, wherein the gate voltage is proportional to the driver voltage. When using a common winding material for at least two gate drivers, the physical properties of the winding material can result in a difference between the driver voltages provided to the respective gate drivers connected to the winding material. This furthermore leads to the fact that a slightly different gate voltage is also applied to the respective power transistors by the gate drivers.In a preferred embodiment of the invention, it can be provided that the power loss of the power transistors is dimensioned by the maximum gate voltage that can be supplied to them in each case, wherein the lowest gate voltage corresponds to the highest power loss. This advantageously makes it possible that, when using a winding material for a plurality of gate drivers, the power losses of the respective power transistors resulting from the different gate voltages are taken into account in the arrangement of the power electronics modules having the power transistors. A difference in the gate voltages of the transistors resulting from the slightly different drive voltages can thus be compensated for by the arrangement of the power semiconductor modules according to the invention. As a result, greater manufacturing tolerances can be accepted during the manufacture of the winding material and a downstream voltage control for achieving identical gate voltages for the transistors can be dispensed with. In gate drivers, which each comprise a separate winding material, it is possible that, for example, during an end-of-line test, the tolerances and / or the values of the output voltage of the winding material are determined. Subsequently, the winding goods can be assigned to the respective gate drivers in such a way that the different gate voltages resulting from the different output voltages are compensated by the arrangement according to the invention of the power transistors or the power semiconductor modules.According to the invention, it is provided that the circuit arrangement comprises three power transistors of identical construction connected to a high-voltage side and three power transistors of identical construction connected to a ground side, wherein the gate drivers of the HV-side power transistors each have a first winding material and the gate drivers of the ground-side power transistors each have a second winding material. In this case, a ground-side power transistor and an HV-side power transistor each form a power electronics module. The transistors are interconnected in such a way that one of the power electronics modules comprises the HV-side power transistor and the ground-side power transistor with the highest power loss, respectively, and that a further power electronics module comprises the HV-side power transistor and the ground-side power transistor with the lowest power loss, respectively. In this way, optimum cooling can be achieved for all power electronics modules or accordingly for all power electronics components by the arrangement according to the invention of these power electronics modules.According to the invention, it can be provided for the coolant line that a liquid coolant, in particular a water-glycol mixture, can flow through it. The arrangement of the cooling device can be effected in such a way that the power electronics modules are in contact with the coolant or that the power electronics modules are in contact with a body of the coolant device enclosing the coolant and thus forming the coolant line. In the case of an arrangement of the power electronics modules in direct contact with the coolant, it can be provided in particular that the power electronics modules have an insulation layer on their surface, which prevents an electrical short circuit in the power electronics modules caused by the coolant.For a motor vehicle according to the invention, it is provided that it comprises a circuit arrangement according to the invention. The circuit arrangement can be designed in particular as a three-phase inverter and can be used for controlling an electric traction motor of the motor vehicle. It is possible for the cooling device of the circuit arrangement to be connected to a coolant circuit of the motor vehicle. This coolant circuit can be implemented in such a way that the cooling device of the circuit arrangement can be flown through in one or more flow directions. Furthermore, the coolant circuit of the motor vehicle can comprise, for example, a pump for conveying the coolant and / or a heat exchanger for discharging the heat absorbed by the coolant or the like.For a method according to the invention for producing a circuit arrangement according to the invention, it is provided that the power electronics modules are arranged along the coolant line or that power electronics modules arranged on the coolant line are connected to further components of the circuit arrangement in such a way that at least one power electronics module which emits a higher power loss than heat during operation of the circuit arrangement is arranged in front of at least one power electronics module which emits a lower power loss than heat with respect to each usable flow direction.The advantage of connecting the power electronics modules to further components of the circuit arrangement in such a way that at least one power electronics module which emits a higher power loss than heat during operation of the circuit arrangement is arranged upstream of at least one power electronics module which emits a lower power loss than heat with respect to each usable flow direction is that the thermal utilization of the power semiconductor modules is improved without having to undertake mechanical changes to the circuit arrangement. This can be advantageous in particular in circuit arrangements which comprise a plurality of similar power electronics modules, the power loss of which during operation is determined in particular by further components of the circuit arrangement which are connected to them in each case.All the explanations and advantages which have been described for the circuit device according to the invention also apply accordingly to the method according to the invention.Further advantages and details of the invention are evident from the exemplary embodiments described below and on the basis of the drawings. The following are shown: FIG. 1 shows a schematic side view of a motor vehicle according to the invention, FIG. 2 shows a sectional side view of a first exemplary embodiment of a circuit arrangement according to the invention, FIG. 3 shows a sectional side view of a second exemplary embodiment of a circuit arrangement according to the invention, and FIG. 4 shows a schematic illustration of a third exemplary embodiment of a circuit arrangement according to the invention.FIG. 1 shows a schematic side view of a motor vehicle 1 according to the invention. The motor vehicle 1 comprises a traction battery 2 for operating an electric traction motor 3. the traction motor 3 of the motor vehicle 1 is operated with three-phase alternating voltage, wherein the motor vehicle 1 comprises a circuit arrangement 4 according to the invention, which is designed as a three-phase inverter and converts the direct voltage provided by the traction battery 2, in particular a high voltage, into a three-phase voltage for operating the electric motor 3.The circuit arrangement 4 comprises a cooling device 5, which is connected to a cooling circuit 7 of the motor vehicle 1 via two coolant lines 6. The cooling circuit 7 of the motor vehicle can comprise, for example, a pump for conveying a coolant, for example a water-glycol mixture, and / or a heat exchanger for releasing heat absorbed by the coolant to the environment of the motor vehicle 1 or the like.FIG. 2 shows a sectional side view of a circuit arrangement 4 according to the invention. The cooling device 5 of the circuit arrangement according to the invention comprises a coolant line 8, which can be operated in a flow direction shown by the arrow 9. During operation of the cooling device 5 or during operation of the circuit arrangement 4, a coolant flows through the coolant line 8 in the direction of the arrow 9. The power electronics modules 11, 12, 13 are in thermal contact with the cooling device 5, so that waste heat occurring in the power electronics modules 11, 12, 13 during operation of the circuit arrangement 4 can be dissipated from the coolant flowing through the coolant line 8, so that the power electronics modules 11, 12, 13 are cooled.In this example, the power electronics module 11 has a higher power loss than the power electronics module 12. The power electronics module 13 furthermore has a lower power loss than the power electronics module 12. The power electronics modules 11, 12, 13 are arranged in such a way that the power electronics module 11 with the highest power loss is arranged at the front with respect to the flow direction. Furthermore, the power electronics modules 11, 12, 13 are arranged in such a way that their power loss decreases along the flow direction. The power electronics module 11, which has the highest power loss, is consequently in thermal contact with the coolant at a location at which the coolant still has the lowest coolant temperature. Due to the heat emitted by the power electronics modules 11, 12, 13, the coolant heats up when flowing through the coolant line 8, and the arrangement according to the invention of the power electronics modules 11, 12, 13 ensures that the power electronics module 11 with the highest power loss is cooled by the coolant with the lowest coolant temperature. As the coolant temperature rises, the waste heat generated by the power electronics modules 12, 13 decreases stepwise along the flow direction, so that particularly advantageous cooling is achieved overall for the entire circuit arrangement 4. In particular, it is possible that, due to this arrangement of the power electronics modules 11, 12, 13, an identical or substantially identical operating temperature is reached for each of the three power electronics modules 11, 12, 13 during operation of the circuit arrangement.FIG. 3 shows a sectional side view of a further exemplary embodiment of a circuit arrangement 4 according to the invention. In this exemplary embodiment, the coolant line 8 of the cooling device 5 can be operated in two flow directions shown by the double arrow 14. It is therefore possible for a coolant to flow through the coolant line 8 during operation in both flow directions shown by the double arrow 14. In order to ensure the most efficient possible cooling of the power electronics modules 11, 12, 13 in this case as well, these are arranged in such a way that the power electronics module 11 with the highest power loss is arranged in the middle. The power electronics module 12, which has a lower power loss than the power electronics module 11, is arranged next to the power electronics module 11, and the power electronics module 13, which has a lower power loss than the electronic power module 12, is arranged on the other side of the power electronics module 11 with respect to the possible flow directions. Thus, for both possible flow directions, the most efficient possible cooling of the power electronics modules 11, 12, 13 is achieved.Both for the exemplary embodiment shown in FIG. 2 and for the exemplary embodiment shown in FIG. 3, it is possible for the circuit arrangement 4 according to the invention to comprise more than three power electronics modules 11, 12, 13. If the circuit arrangement 4 comprises two or more power electronics modules with an identical power loss, these are arranged next to one another in both exemplary embodiments with respect to the flow direction. In the case of an even number of power electronics modules, in the exemplary embodiment illustrated in FIG. 3, the power electronics module can be the one with the highest power than one of the two power modules of the pair of power electronics modules arranged in the middle of the arrangement.FIG. 4 shows a schematic view of a circuit arrangement 4 designed as a three-phase inverter. The power electronics modules 11, 12, 13 are designed as half bridges each comprising two transistors 15 a- 15 f. The transistors 15 a- 15 fare power transistors and can be embodied, for example, as IGBTs or as MOSFETs. In addition to the two transistors 15 a- 15 f, each power electronics module 11, 12, 13 comprises in each case two free-wheeling diodes 16 a- 16 f, which can be formed as separate components or as components integrated into the respective transistors 15 a- 15 f. The circuit arrangement further comprises a high-voltage side 17 and a ground side 18 and a capacitor 19 arranged on the input side.During operation of the circuit arrangement 4, the power electronics modules 11, 12, 13 embodied as half bridges can convert a direct voltage present on the input side between the terminals 20, 21, which direct voltage is provided, for example, by the energy store 2, into a three-phase output voltage for operation of the electric motor 3. The DC voltage can be, in particular, a high voltage.For voltage conversion, each of the transistors 15 a- 15 fis driven via a respective gate driver 22 a- 22 f. The gate drivers 22a-22f each set the gate voltage for switching the transistors 15a-15f associated with them. The gate drivers 22 a- 22 foperate as level converters, wherein they each convert a driver voltage into the gate voltage for switching the respective transistor 15 a- 15 f. The gate drivers 22 a, 22 cand 22 eare provided with the driver voltage via a winding material 23, corresponding to the gate drivers 22 b, 22 dand 22 fvia a winding material 24. By means of a winding material and the gate drivers connected to the winding material, a blocking converter can be formed, for example.The winding material 23 comprises the taps 25 a, 25 cand 25 e, via which the gate drivers 22 a, 22 cand 22 eare supplied with a driver voltage. The gate drivers 22a, 22c and 22e convert this driving voltage into the gate voltage for driving the high-voltage side transistors 15a, 15c and 15e. Correspondingly, the winding material 24 comprises the taps 24 b, 24 cand 24 f, with which the gate drivers 22 b, 22 dand 22 fof the transistors 15 b, 15 dand 15 farranged on the ground side 18 are controlled. The gate drivers 22 a- 22 fcan be operated via the winding goods 23, 24, for example from a low voltage of a network, for example of an on-board network of a motor vehicle. In this case, the winding materials can achieve a galvanic separation between the low voltage and the high voltage of the grid. Alternatively, it is possible that all or a part of the gate drivers 22 a- 22 fare supplied via the high voltage of the grid.The gate drivers can each be connected to a microcontroller 27, wherein the connecting lines are not shown here for reasons of clarity. The microcontroller 27 can control the driving of the transistors, i.e. the switching of the transistors 15a-15f, as a result of which the alternating direction of the DC voltage is achieved.The winding goods 23 and 24 have, due to their construction, slight differences between the drive voltages provided at the taps 25 a, 25 cand 25 eand 26 b, 26 dand 26 f, respectively. As a result of the level conversion of the drive voltages, the gate voltages with which the transistors 15a-15f are driven also have slight differences. As a result, the transistor supplied with the lowest gate voltage exhibits the highest thermal power loss, for example due to forward losses and / or switching losses. In order to achieve the arrangement of the power electronics modules according to the invention, the transistors 15 a- 15 fand the gate drivers 22 a- 22 fare connected to the winding goods 23 and 24, respectively, in such a way that the transistors 15 aand 15 beach receive the lowest gate voltage, the transistors 15 cand 15 dare each receive the medium gate voltage and the transistors 15 eand 15 fhave the highest gate voltage. For this purpose, the gate grinders 22 a- 22 fare connected to the winding material in such a way that the gate driver 22 ais connected to the tap 25 athat provides the lowest drive voltage of the winding material 23, the gate driver 22 cis connected to the tap 25 cof the winding material 23 that provides a medium drive voltage, and the gate driver 22 eis connected to the tap 25 ethat provides the highest voltage of the winding material 23. Correspondingly, the gate driver 22 bis connected to the tap 26 bproducing the lowest drive voltage of the winding material 24, the gate driver 22 dis connected to the tap 26 dof the winding material 24 producing a medium drive voltage, and the gate driver 22 fis connected to the tap 26 fproducing the highest voltage of the winding material 23. Consequently, the transistors 15a and 15b have the highest power loss and the transistors 15e and 15f have the lowest power loss, the power loss of the transistors 15c and 15d being intermediate between those of the transistors 15a and 15b and 15e and 15f.The power electronics module 11 forming the first half bridge of the transistors 15 aand 15 btherefore has the highest power loss, the power loss of the power electronics module 12 is consequently somewhat lower than that of the power electronics module 11 and the third power electronics module 13 overall has the lowest power loss. The loss line of the individual power electronics modules 11, 12, 13 is determined in this exemplary embodiment decisively by the power loss of the transistors 15 a- 15 f.For reasons of clarity, the cooling device 5 is not shown in FIG. 4, which is arranged on the circuit arrangement 4 in such a way that it can be operated in the flow direction shown by the arrow 28. The power electronics module 11 with the highest power loss is arranged at the front with respect to the flow direction. The power electronics modules 12, 13 are furthermore arranged in such a way that their power loss decreases in the direction of flow. The arrangement of the cooling device is effected in such a way that the power electronics modules 11, 12, 13 are in thermal contact with the cooling device. This can preferably be realized in that in particular the transistors 15 a- 15 fare in thermal contact with the cooling device. In this way, a particularly efficient cooling of the circuit arrangement 4 is achieved. In particular, the arrangement of the power electronics modules 11, 12, 13 optionally enables an increase in the power of the circuit arrangement 4 with a constant component area or the reduction in the component area with a constant power. The component area can relate in particular to the chip area of the respective power electronics module required for realizing the transistors 15 a- 15 f. By using two winding products 23, 24 for controlling six gate drivers 22 a- 22 f, the circuit complexity can furthermore be reduced.The effect of the arrangement of the power electronics modules 11, 12, 13 is to be illustrated below with reference to a numerical example. The first table below shows a normalized power loss P n, the respective coolant temperature at the power electronics module T c and the junction temperature of the respective transistors 15 a- 15 fof the respective power electronics module for the power electronics modules (LEMs) 11, 12, 13.P n104%100%96%T c60 °C64 °C68° CT J164°C164°C164°CDue to the power loss-dependent arrangement of the power electronics modules 11, 12, 13, the respective transistors 15 a- 15 fprovide an identical junction temperature. The values for the barrier layer temperature and for the coolant temperature are to be understood here purely as examples; of course, the barrier layer temperature and / or the coolant temperature can also assume higher or lower values.In the case of an arrangement of power electronics components each having an identical normalized power loss P n the distribution of the coolant temperature T c and the junction temperature T J of the respective transistors 15 a- 15 fof the respective power electronics module shown in the following second table would result:P n100%100%100%T c60 °C64 °C68° CT J160° C164°C168° CIf the power electronics module with the highest power loss were to be arranged only at the end with respect to the flow direction, an even greater difference would result in the junction temperature T J of the respective transistors 15 a- 15 f.It is of course also possible for the coolant device not shown in FIG. 4 to be operable in two flow directions, wherein an arrangement of the power electronics modules 11, 12, 13 or an arrangement of the transistors 15 a- 15 for the connection of the gate drivers 22 a- 22 fto the winding materials 23, 24 is carried out in accordance with the exemplary embodiment already shown in FIG. 3. In this way, advantageous cooling of the circuit arrangement 4 can be achieved even in the case of a cooling device through which flow can take place in two flow directions, since the disadvantageous case in which the power electronics module with the highest power loss is arranged only at the end with respect to the flow direction is avoided in the case of both flow directions.

Claims

Circuit arrangement (4) comprising at least three power electronics modules (11, 12, 13) and a cooling device (5) for cooling the power electronics modules (11, 12, 13), wherein the cooling device (5) comprises a coolant line (8) through which a coolant can flow, which can be operated in exactly one flow direction or in two flow directions, wherein the power electronics modules (11, 12, 13) are arranged along the coolant line (8) in such a way that at least one power electronics module (11, 12, 13) which emits a higher power loss than heat is arranged in front of at least one power electronics module (11, 12, 13) which emits a lower power loss than heat with respect to each usable flow direction, wherein the power electronics modules (11, 12, 13) are half bridges which each comprise two power transistors (15a - 15f), wherein the power transistors (15a-15f) are each driven via a gate driver (22a-22f), wherein at least three of the gate drivers (22a-22f) have a common item of winding material (23, 24), which provides a drive voltage for the at least three gate drivers (22a-22f), wherein the circuit arrangement (4) comprises three identically constructed power transistors (15a, 15c, 15e) connected to a high-voltage side and three identically constructed power transistors (15b, 15d, 15f) connected to a ground side, wherein the gate drivers (22a, 22c, 22e) of the high-voltage-side power transistors (15a, 15c, 15e) each have a first item of winding material (23) and the gate drivers (22b, 22d, 22f) of the ground-side power transistors (15b, 15d, 15f) each have a second item of wound material (24), wherein the power transistors (15a-15f) are interconnected in such a way that one of the power electronics modules (11, 12, 13) each comprises the high-voltage-side power transistor (15a, 15c, 15e) and the ground-side power transistor (15b, 15d, 15f) with the highest power loss and a further power electronics module (11, 12, 13) each comprises the high-voltage-side power transistor (15a, 15c, 15e) and the ground-side power transistor (15b, 15d, 15f) with the lowest power loss.Circuit arrangement according to Claim 1, characterized in that, in the case of exactly one flow direction, all the power electronics modules (11, 12, 13) are arranged along the coolant line (8) in such a way that a power electronics module (11, 12, 13) having a second, lower or identical power loss follows a power electronics module (11, 12, 13) having a first power loss.Circuit arrangement according to Claim 1, characterized in that, in the case of two throughflow directions, at least three power electronics modules (11, 12, 13) are arranged along the coolant line (8) in such a way that the power electronics module (11, 12, 13) having the highest power loss is arranged at one of the at least one central position.Circuit arrangement according to one of the preceding claims, characterized in that the power transistors (15a - 15f) are designed as IGBTs or as MOSFETs.Circuit arrangement according to one of the preceding claims, characterized in that the gate drivers (22a - 22f) generate a gate voltage of the power transistors (15a - 15f), wherein the gate voltage is proportional to the driver voltage.Circuit arrangement according to one of the preceding claims, characterized in that the power loss of the power transistors (15a - 15f) is dimensioned by the maximum gate voltage which can be supplied to them in each case, the lowest gate voltage corresponding to the highest power loss.Circuit arrangement according to one of the preceding claims, characterized in that a liquid coolant, in particular a water-glycol mixture, can flow through the coolant line (8).Motor vehicle, comprising a circuit arrangement (4) according to one of the preceding claims.Method for producing a circuit arrangement (4) according to one of Claims 1 to 7, wherein the power electronics modules (11, 12, 13) are arranged along the coolant line (8) or wherein power electronics modules (11, 12, 13) arranged on the coolant line (8) are connected to further components of the circuit arrangement (4) in such a way that at least one power electronics module (11, 12, 13) which emits a higher power loss than heat during operation of the circuit arrangement (4) is arranged in front of at least one power electronics module (11, 12, 13) which emits a lower power loss than heat with respect to each usable throughflow direction.

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