WO2018138017A1

WO2018138017A1 - Semiconductor module

Info

Publication number: WO2018138017A1
Application number: PCT/EP2018/051340
Authority: WO
Inventors: Christoph Berndt Marxgut; Swen Ruppert
Original assignee: Siemens Aktiengesellschaft
Priority date: 2017-01-25
Filing date: 2018-01-19
Publication date: 2018-08-02
Also published as: DE102017206553A1

Abstract

The invention relates to a semiconductor module for a power electronics circuit having a plurality of power electronics switch cells connected in parallel, wherein different switch cells of the plurality of switch cells are assigned to different groups of switch cells such that any given group of switch cells comprises at least one switch cell, but not all switch cells. Each of the switch cells comprises an individual gate connection g for the individual control of the respective switch cell, wherein gate connections of different switch cells are not directly connected to each other and therefore the different switch cells of the module can be actuated by a control independently of each other by means of individual gate signals.

Description

description

Semiconductor module The invention relates to a semiconductor module for a

Power electronics circuit, which should be used in particular for an electric or hybrid-electric drive system for an aircraft. For propulsion of aircraft such as aircraft or helicopters, concepts based on electric or hybrid-electric propulsion systems are being investigated and used as an alternative to the conventional internal combustion engines. Such a drive system generally has at least one electric machine, which is operated to drive the propulsion means of the aircraft as an electric motor. Further, a source of electrical energy for supplying the electric motor as well as a rule are a Leis ^¬ consumer electronics provided by means of which the electric motor is operated. In the case of a hybrid electric drive system, furthermore, an internal combustion engine is provided, which, for example, is serially integrated into the drive system and, for example, drives a generator, which in turn provides electrical energy stored in a battery and / or supplied to an electric motor can be. Depending on the configuration of the system, the power electronics connected upstream of the electric motor can be embodied as rectifiers, inverters or frequency converters and provide the electric motor with the electrical energy required for its operation in the suitable form.

When electrically operating the aircraft, a fault in the drive system can result in a crash of the aircraft result, coupled with corresponding risks to passen- gers and usually accompanied by considerable Sachschä ^¬. In the electric drive system, a fault among others in the energy storage, which supplies the electrical energy for supplying the electric motor, in the electric motor and / or in the power electronics introduced above.

Such power electronics, which can be embodied as described above and in WO2016005092A1, for example as a power converter, typically has a plurality of power semiconductors, for example IGBTs (insulated gate bipolar transistor), MOSFETs (metal oxide semiconductor field effect transistor), diodes, etc. a failure in such power semiconductors, eg. caused by excessive currents to ho he ^¬ frequencies, or by internal defects, resulting in a power converter that has no redundancy, directly to the failure of the entire converter. For applications where availability and reliability are essential, it is essential to develop redundant designs.

A pragmatic approach is to provide the inverter as a whole at least twice, in order to activate the other inverter in case of failure of one of the two inverters, so that this takes over the function of the failed first inverter. This approach has the disadvantage that weight, cost and volume of the system greatly raised stabili ^¬ hen.

Another possibility is eg. In WO2016 / 005166A1 be ^¬ wrote. There it is proposed to provide the power semiconductors of the inverter several times. This is realized by redundantly implemented modules, wherein the individual power semiconductors of a common, non-redundant converter are replaced by these modules, wherein in a respective module several power semiconductors or switching cells possibly including a corresponding fuse summarized and their gate terminals simultaneously be controlled. If one of the power semiconductor module, a functi ^¬ on the module and thus the inverter is maintained, since one of the further power semiconductor module assumes the role of the failed power semiconductor. Despite this measure, However, in order to increase the availability, errors, for example in the gate control of the switching cells, can still lead to the failure of an entire module. It is therefore an object of the invention to provide a way to improve the reliability of a power electronics circuit.

This object is achieved by the semiconductor module described in claim 1 and by the method described in claim 9

Operating procedure solved. The subclaims describe advantageous embodiments.

A semiconductor module has a multiplicity of power electronic switching cells connected in parallel, wherein different switching cells of the plurality of switching cells are assigned to different groups of switching cells in such a way that each group of switching cells has at least one switching cell, but not all switching cells. Each of the switching cells has an individual gate connection g for individually controlling the respective switching cell, wherein gate connections of different switching cells are not directly connected to each other, so that the different switching cells of the module can be controlled independently of one another by individual gate signals are. Consequently, the semiconductor module has a number of terminals corresponding to the number of switching cells for connecting the individual gate terminals to the controller. The term "not directly connected" is intended to indicate that a control signal from the controller, which is supplied to a first switch cell does not automatically also achieved ei ^¬ ne second Sachaltzelle of the module. The switching cells are indeed substantially directly connected to the controller, not Of course, it is not excluded that the second switch cell receives the same control signal as the first switch cell, but this is only possible on the way that the controller controls this Control signals individually to the second switching ^{cell ¬} leads.

The inventive concept underlying this is that a power electronics circuit is configured such that the circuit comprises a plurality of semiconductor modules, wherein in each of the semiconductor modules more switching cells or Leis ^¬ semiconductor processing are integrated. Each switching cell, for example an IGBT or a MOSFET, has, inter alia, a gate connection or contact, wherein the individual gate connections of the ^different switching cells of the respective module can be controlled individually and basically independently of one another by a control of the power electronics circuit. An important point here is that a switching cell is a single IGBT or MOSFET or similar. is, but not an interconnection of several such semiconductors. The number of separate switching cells is arbitrary in each module and can be selected depending on Redun ^¬ danzbedarf. In contrast to modules in which a plurality of parallel switched ^¬ te switching cells are driven with only one, common gate signal, each cell can be switched or controlled individually by means of a separate gate signal in this realization. As a result, errors that affect the gate drive itself, for example, a failure of the gate driver of one of the switching cells, not directly to the failure of the module, since not every cell is affected by this error.

If, for special applications, an advantage results from the fact that all the switching cells are operated in parallel, that is to say all switching cells or their gate connections are switched in the same way, as in FIG

WO2016 / 005166A1, this is still possible with the modules described here.

It can be provided a sensor which thermally monitors each group of switching cells individually thermally, wherein the individual control of the various switching cells in Depending on a respective result of the thermal monitoring takes place. For example. If, for one group, an increased, possibly critical temperature is determined, this group can be deactivated and another group activated.

In this context, the number of thermal cycles in the active and / or deactivated state can also be monitored for the switching cells. This allows on the one hand that a uniform loading of different switching groups of cells is ensured and can be used for maintenance of the modules also by means of lifetime ^¬ model.

It is provided a variety of cooling circuits for cooling the switching cells, wherein the cooling circuits are arranged to ^¬ such that different cooling circuits cool different groups of switching cells. The controller is then set up to control the various cooling circuits in such a way that an operating switching cell is cooled more strongly than a switching ^cell not in operation. The cooling is therefore activated for those groups that are in operation at a particular time and throttled for those groups that are not in operation at the time.

The use of such cooling circuits in turn increases the redundancy in the cooling system and, secondly, reduces the influence of thermal cycles which influence the life of a semiconductor module, which has a positive effect on the service life. There are portions or Schaltzel ^¬ len that are active, targeted cooled while the cooling of the ranges or switching cells, which is not active, targeted ge ^¬ is throttled in order to know the semiconductor for example. No additional passive temperature fluctuations when by changed ambient conditions should change the temperature of the cooling medium. At least some of the switching cells advantageously have different dielectric strengths. Cosmic radiation is a source of interference, especially in aviation, which can lead to the failure of power electronic converters. To minimize the influence of the radiation, power modules are typically utilized only to a certain degree of their specified withstand voltage (eg up to 40% -60%), which leads to a considerable oversizing of the converter. In addition, the required high dielectric strength of the switching cells comes at the expense of higher Leit ^¬ losses, which reduces the efficiency of the inverter. The modules presented here could consist of switching cells of different voltage strengths, which are then controlled at the respective operating point in such a way that either switching cells are activated whose behavior is optimized for immunity to cosmic radiation or switch cells that are fully utilized and thus the efficiency improve the converter. In this case, the controller is set up in such a way that the switching cells are controlled or operated in such a way that either switching cells are activated whose behavior is optimized for the greatest possible degree of immunity to cosmic radiation, or switching cells are activated which can be used up to their maximum dielectric strength.

Advantageously, different switching cells via un ^¬ terschiedliche communication channels are controlled. For example. one group of switch cells is electrically driven, while another group is optically driven. This also has a positive effect on the degree of redundancy of the semiconductor module.

Furthermore, different switching cells may have different switching speeds and / or be based on different semiconductor technologies. A module can therefore consist of different semiconductor switch technologies. It is thus conceivable, for example, for an IGBT cell to be parallel to a MOSFET cell is arranged. Since each cell is separately controllable, the module can connect the best of the two technologies. The switching cells can also be assigned in each case a fuse, wherein the fuse is in each case designed and interconnected with the associated switching cell that at overcurrent load of the fuse associated switching cell, the respective switching cell is functionally separated from the module, ie the respective fuse blows. The Siche ^¬ approximations can, for example, from one or more bond wires are made to separate in case of current stress the corresponding cell from the module. The separate control of each switching cell and each cell could be a different Si insurance and an individual current capacity supplied ^¬ item. Thus, the value of the overcurrent shutdown can be changed during operation by means of the correct gate signal control depending on the application or operating point. In one embodiment, not all, but at least one of the switching cells each associated with a fuse, each of said fuses is constructed and interconnected with the at ^¬ parent switching cell, that in Überstrombe ^¬ anspruchung of the associated fuse switch cell the respective switch cell functionally from Module is disconnected, and wherein the controller is arranged such that in a normal operation of the semiconductor module only switching cells are used, which is associated with a fuse, and only in the presence of a fault in the semiconductor module, a switching cell is used without associated fuse. For example. ^¬ can be here at various cubicles with fuses equipped kitchens ^¬ tet that trigger at different current levels.

In a method for operating a power electronics circuit with such a semiconductor module, therefore, at least at times, if not constantly, different switching cells of the semiconductor ^module are driven simultaneously with different control signals. Each group of switching cells can be monitored individually thermally, in which case the individual control of the various switching cells takes place as a function of a respective result of the thermal monitoring.

Advantageously, the groups of switching cells can be operated alternately such that in a first time period only a first group of switching cells is operated, while a second group of switching cells is not operated in the first time period. Consequently, in a second period following the first period, only the second group of switching cells is operated, while the first group of switching cells is not operated in the second period, and so on.

By alternately operating the individual switching cells or groups of switching cells, thermal balancing of the module can be achieved and thus the reliability of the module can be improved. The respective subset of the cells which are put into operation at the same time can also be advantageously distributed thermally on the module. The terms "run" or "in use" or "acti ^¬ fourth" etc. are to be understood as that a for example. "Rate at work ^¬" switch cell from the controller located so attached is ^¬ controlled to be the intended Task completed. It will therefore be present at the gate terminal of a switching cell in operation a corresponding kind of control signal. If a switching cell is not in operation, there will typically be no signal at the gate terminal.

In contrast to the aforementioned possibility of achieving redundancy by adding a further converter, weight saving can be achieved on account of the compact module structure presented here and the resulting converter design, since housing, wiring, carrier germaterialien and gate driver circuits can be saved.

The design of the gate driver circuits of the module described herein can increase reliability in several ways:

The individual switching cells can be controlled with different communication channels. For example. one group of switch cells is electrically driven, while another group is optically driven.

Further advantages and embodiments will become apparent from the drawings and the corresponding description.

In the following the invention and exemplary embodiments will be explained in more detail with reference to drawings. There, the same components in different figures are identified by the same reference numerals.

Show it:

1 shows a schematic representation of an inverter,

2 shows a module of the converter in a first embodiment,

3 shows the module in a development.

1 shows the power electronics circuit 1 known from WO2016005092A1 and designed there as a converter, which has a rectifier 2, an intermediate circuit 3, an inverter 4 and a control device 5. Via the converter 1, a voltage source 6 (for example an electric generator) and an electrical consumer 7 (for example an electric motor) can be coupled together. The voltage source 6 can be connected to the rectifier 2 via phase lines 8. The consumer 7 can be connected via phase lines 9 to the inverter 4 be. AC voltages of different phases can be transmitted in each case via the phase lines 8, 9.

From the AC voltages of the phase lines 8, a DC voltage 10 can be generated by the rectifier 2, which is fed into the DC link 3. The intermediate ^¬ circle 3 may have a positive line 11 and a minus line 12, between which the DC voltage 10 is applied. The positive lead 11 and the negative lead 12 can terie a Bat-13 may be an intermediate circuit capacitor 14 and coupled through which an intermediate circuit capacitance C bereitge ^¬ represents is. The plus line 11 and the minus line 12 couple the rectifier 2 and the inverter 4, respectively. The plus line 11, the minus line 12 and the phase lines 8, 9 may each be provided, for example, by a wire or a bus bar.

During operation of the converter 1, the converter 1 converts the alternating voltages in the phase conductors 8 into alternating voltages, which are supplied to the load 7 via the phase conductors 9.

The rectifier 2 and the inverter 4 each have half bridges 17, each of which connects or connects the plus line 11 and the minus line 12 to another one of the phase lines 9. For clarity, only two of the half bridges 17 are provided with a reference numeral. Each half-bridge 17 may include two switch assemblies 18, have ^¬ 19th At each half-bridge 17, the switch ^arrangement 18 connects the plus line 11 to the respective phase line 9. The switch arrangement 19 connects the minus line 12 to the same phase line 9. By alternately switching the switch arrangements 18, 19 in the rectifier 2, the process is performed in a manner known per se an AC voltage of one of the phase conductors 8, the DC voltage 10 is generated. By alternately switching the switch assemblies 18, 19 in the changeover Judge 4 is impressed or generated in a conventional manner from the DC voltage 10 in each case a phase conductor 9, an AC voltage. The rectifier 2 and the inverter 4 may have the same circuit topology, ie they may be of identical construction.

For providing the said redundancy, the rectifier 2 and the inverter 4 have the switch arrangements

18, 19 each formed as semiconductor modules, which as ^¬ rin manifests itself in that each semiconductor module 18, 19, a plurality Leis ^¬ tung semiconductor or switching cells 20, 21 has. Each switching cell 20, 21 is a separate fuse 22 connected in series. In each switch assembly 18, 19 so a parallel circuit of a plurality of series circuits or switching branches Z is provided, each switching branch Z is formed on the basis of a switching cell 20, 21 and a fuse 22. Each switching cell 20, 21 may, for example, be designed as an IGBT or MOSFET.

For controlling the switch arrangements 18, 19 of the half bridges 17, common control terminals G of the switch arrangements 18, 19 are used in WO2016005092A1. A respective control connection G of each switch arrangement 18, 19 is coupled on the one hand to the control device 5 and on the other hand to gate inputs g of the switch cells 20, 21 of the respective switch arrangement 18, 19, so that all switch cells 20, 21 of a respective switch arrangement 18, 19 receive the same control signals. The sake of completeness angedeu ^¬ tet for one of the switching devices 18 of the inverter 4, in addition to the common control terminal G, this also has a common collector terminal C and an emitter terminal E the Common ^¬ men. The same applies to the remaining switching arrangements 18, 19 of the inverter 4 and the rectifier 2, but is not shown for the sake of clarity. In FIG. 1, each module 18, 19 is equipped with two switch cells 20, 21, but it is conceivable that more than two switch cells per module are provided to further improve the redundancy or the reliability. These would be connected in an analogous manner, that is, the emitter contacts e of the switching cells would be connected to the common emitter terminal E of the module, the collector contacts k of the switching ^¬ cells would be connected to the common collector terminal C of the module and the gate-input g of the circuit cells would connected to the common gate or control terminal G of the module.

For further explanation of the operation of this known converter, reference is made to WO2016005092A1.

FIG. 2 shows a modification of the power electronics circuit 1 shown in FIG. 1, in particular with respect to the semiconductor modules 18, 19. Since these modules 18, 19 are constructed identically, the module 18 will be described below by way of example, the explanations regarding the structure and mode of operation apply in the same way for the module 19.

The module 18 has, by way of example, four switching cells 20a, 20b, 20c, 20d, whose collector contacts in turn fuses on Si 22 are connected to the common collector terminal K of Mo ^¬ duls 18th Of course, in turn, more or less than four switching cells 20 may be provided. The emitter contacts e of the switching cells 20a, 20b, 20c, 20d are also connected to the common emitter terminal E of the module 18 as in FIG. Unlike the execution of the

Module 18 of Figure 1, however, the gate or control are now contacts ^¬ g of switching cells 20a, 20b, 20c, 20d no longer connected to each other and no longer with the common control terminal of the module. Consequently, the semiconductor module 18 has a number of terminals ga, gb, gc, gd corresponding to the number of switching cells 20a-20d for connecting the individual gate terminals g to the controller 5. Advantageously, the gate contacts g are the Switching cells 20a, 20b, 20c, 20d connected via the terminals or Kon ^¬ clocks ga, gb, gc, gd of the module 18 to the controller 5 such that the controller 5, the switching cells 20a, 20b, 20c, 20d independently and individually can drive. The semiconductor module 18 thus comprises a plurality of parallel-connected power electronic switching cells 20a, 20b, 20c, 20d, each having an individual gate connection g for the individual control of the respective

Switching cell 20a, 20b, 20c, 20d, wherein the switching cells 20a, 20b, 20c, 20d of the module 18 by the controller 5 are independently controllable with individual, possibly different gate or control signals.

The separate control of the individual switching cells 20a, 20b, 20c, 20d by the controller 5 leads to an increase in the degree of freedom with respect to the stress of the module 18. In addition to the general improvement in redundancy, the increased flexibility results in further advantages. For example, the controller 5 may be configured such that only some of the switching cells 20a-20d, but not all, are used in the operation of the converter 1. Thus, only part of the switching cells 20a-20d of the module 18 are operated simultaneously. For example. can each switching cell 20a, 20b, 20c, 20d are thermally monitored using ent ^¬ speaking sensors 31 and spruchung protected or charged depending on the stresses. The sensors 31 are connected to the controller 5, so that these ansteu ^¬ ren, the switch cells 20a-20d in response to the sensor data suitable. For example. this can be made such that when Sensorda ^¬ th, suggesting 20a to an elevated critical temperature of the cubicle, the controller 5, the switching cell

20a at least temporarily deactivated and instead uses one or more of the other switching cells 20b-20d.

The FIG 2 further indicates that the switching cells 20a-20d may be assigned to different groups 41, 42 of switching cells. Each group 41, 42 of switching cells has at least one of the switching cells 20a-20d of the module 18, but not all of the switching cells 20a-20d of the module 18. For example, a first group 41 comprises the switching cells 20a, 20b, while a second group 42 comprises the switching cells 20c, 20d. However, the assignment of switching cells 20a-20d to the groups 41, 42 can be adapted at any time by means of the controller in a suitable manner. As well have introduced additional groups as required or assigned to existing groups are removed using the Steue ^¬ tion.

The controller 5 may be configured such that the Grup ^¬ pen 41, 42 are operated alternately by switching cells. That is, in a first period, only the switching cells 20a, 20b of the first group 41 are used while the switching cells 20c, 20d of the second group 42 are not active. In a subsequent second period, on the other hand, only the switching cells 20c, 20d of the second group 42 are used while the switching cells 20a, 20b of the second group 41 are not active, etc. For the sake of clarity, it will be understood that this mode of operation also includes the option that the individual switching cells 20a-20d of the module 18 are alternately be ^¬ exaggerated, since the above definition of "group" which also provides for the case that the groups each have only a single switching cell. This would mean that, for example, first the switch cell 20a, then the cell 20b, then the

Cell 20c, and finally the cell is activated 20d, currency ^¬ rend each other cells are not used. It is also conceivable that, for example, the cells 20a, 20b each form an egg ^¬ gene group for themselves, while the cells 20c, 20d are assigned to a common group, and that these three groups are operated alternately.

With regard to the thermal monitoring described above, it should be noted that it may be sufficient if necessary, that not necessarily each switching cell 20a-20d is thermally monitored, but only one switching cell per group. The described alternating operation of the groups 41, 42 he ^¬ laubt a thermal balancing of the module 18 and thus egg ^¬ ne further improvement of the reliability of the module 18. The respective subset of the switching cells which are associated with a common men group and accordingly gleichzei ^¬ tig be put into operation, can be distributed thermally advantageous on the module 18.

In an advantageous development, a plurality of cooling circuits 51, 52 for cooling the switching cells 20a-20d are present. For example. For each group 41, 42 an individually assigned and operated by the controller 5 as needed cooling circuit 51, 52 may be provided. The controller 5 is accordingly set up to control the various cooling circuits 51, 52 in such a way or with a suitable one

To apply cooling medium that for those groups 41, 42, which are in operation at a particular time, the cooling is activated and for those groups 41, 42, which may not be in operation at the time, the cooling is throttled ,

By this measure, the influence of thermal cycles that affect the life of a semiconductor module 18 can be reduced. The life span can also be positively influenced by adapted, individual cooling, for example by selectively cooling the groups in operation, for example the first group 41, while selectively throttling the cooling of the groups which are not in operation, for example group 42 is, so that the individual switching cells 20a-20d, for example, learn no additional passive temperature fluctuations, if the temperature of the cooling medium should change due to changes in ambient conditions.

In addition, the separately controllable switch cell groups 41, 42 of the module 18 can be connected to a cooling plate (not shown) of different sizes, in order to find a compromise between common-mode EMC emissions and thermal connection. A big Although connection surface to the cooling plate guarantees good ther ^¬ mical properties because of ei ^¬ nes correspondingly low thermal resistance, but a high parasitic capacitance between the switching cell and heat sink, resulting in high common mode EMC emissions.

In order to address the harmful effects of cosmic radiation in addition to the mentioned thermal influences, the module has 18 switching cells of different dielectric strength. For example. For example, the switching cells 20a, 20b of the first

Group 41 may be designed so that they work reliably even at the ^expected he ^¬ waiting strong cosmic radiation at high altitude. This requires that the switching cells 20a, 20b be allowed to operate only to a certain degree, for example 40-60%, of their specified dielectric strength, which ultimately means that they must be made very oversized in order to still provide the required power to be able to. The switching cells 20c, 20d of the second group 42, on the other hand, would be designed so that they can be fully utilized and exploited, which makes them less reliable for operation with appreciable cosmic radiation, but ver ^¬ speaks at low altitudes that the module 18th and thus the inverter 1 operates with ho ^¬ her efficiency.

The controller 5 would thus operate the thus equipped first group 41 when the aircraft is at a level with significantly increased cosmic radiation, while dispensing with the use of the first group 41 due to the non-optimal efficiency when the altitude and thus the cosmic radiation is lower. In the latter case, the controller 5 would operate the module 18 with the hocheffizien ^¬ th second group 42 with the switch cells 20c, 20d.

Alternatively or additionally, the switching cells 20a-20d may be selected differently such that the switching cells 20a, 20b or 20c, 20d of the various groups 41, 42 via different communication channels are controlled Kings ^¬ nen. For example. For example, the switching cells 20a, 20b of the first group 41 are electrically driven, while the switching cells 20c, 20d of the second group 42 are optically driven.

Also alternatively or additionally, the switching cells 20a-20d may be selected differently such that the switching cells 20a, 20b, 20c, 20d of the various groups 41, 42 are based on different semiconductor switch technologies. For example. For example, the switching cells 20a, 20b of the first group 41 may be MOSFET cells, while the switching cells 20c, 20d of the second group 42 may be IGBT cells. It is also conceivable that the cells of a group are based on different semiconductor switch technologies. Since each cell 20a-20d is separately controllable, the module 18 with the aid of

Control 5, depending on the situation, use the best technology. For example. For example, the controller may operate to turn on a MOSFET based switch cell 20a, 20b just before an IGBT based switch cell 20c, 20d to avoid the high turn on losses of the IGBT. As soon as the voltage across the MOSFET cell 20a, 20b has dropped, the IGBT cell 20c, 20d can be switched on with low loss and take over the current because of its good conducting properties. The switching off of the module 18 is initiated by the low-loss switching off of the IGBT cell 20c, 20d. Of the

Current then commutes briefly to the MOSFET switching cell 20a, 20b, before it can then be turned off.

FIG. 3 shows a semiconductor module 18 in a modification modified to the effect that not all switching cells 20a-20d are assigned a fuse 22. In the example shown, only the switching cells 20a, 20c are each assigned its fuse 22, while the switching cells 20b, 20d are integrated into the module 18 without a fuse. As a result, the module 18 can be used in normal operation with fuse 22 and only in case of failure is an unsecured switching cell 20b, 20d ^¬ controls or used. Each switching cell 20a-20d can be optimized with respect to the switching behavior by the respective gate driver circuit, for example by adjusting the gate resistances, the gate voltage, the maximum gate current, etc. Thus, a development of the switching speed within the Module 18 can be achieved in order to limit voltage spikes due to different parasitic inductances, and to completely exhaust the limits of each switching cell 20a-20d of the module 18. Such gate drive circuits are, for example, on a separate board arranged, which lies very close to the supplied ^¬ hearing module in order to minimize parasitic effects. The controller 5 supplies the gate driver circuit with corresponding control signals. Each switching cell 20a-20d can also, by specially ausgeleg ^¬ te gate driver circuits, a certain Schaltgeschwindig ^¬ speed (di / dt and dv / dt) can be assigned, which is depending on the Ar ^¬ beitspunkt used. Thus, no compromise between ^¬ switching losses and permissible EMC emissions must be received, but you can operate the module 18 depending on the requirements in the optimal operating mode.

The flexible structure of the module 18 also allows the sepa ^¬ rierte fuse of diode and switching cell. Depending on the failure rate, the number of switching cells and the number of diodes can also be different. For example, a module could consist of five active switching cells (eg IGBTs) and two diodes if, in a previous analysis, diodes have been shown to have a much lower probability of failure.

Claims

claims

1. Semiconductor module (18) which has a multiplicity of power electronic switching cells (20a, 20b, 20c, 20d) connected in parallel, wherein different switching cells (20a,

20b, 20c, 20d) of the plurality of switch cells (20a, 20b, 20c, 20d) are assigned to different groups (41, 42) of switch cells (20a, 20b, 20c, 20d) such that each group (41, 42) of switching cells (20a, 20b, 20c, 20d) at least one switching cell (20a, 20b, 20c, 20d), but not all switching cells (20a, 20b, 20c, 20d), wherein

- each of the switching cells (20a, 20b, 20c, 20d) a individu ^¬ economic gate terminal (ga, gb, gc, gd) (, 20d 20a, 20b, 20c) for individually controlling the respective switching cell,

Gate terminals (ga, gb, gc, gd) of different switching cells (20a, 20b, 20c, 20d) are not directly connected to each other, so that the different switching cells (20a, 20b, 20c, 20d) of the semiconductor module (18) of a controller (5) are independently controllable with individual gate signals.

2. The semiconductor module (18) according to claim 1, characterized in that a sensor (31) is provided which individually thermally monitors each group (41, 42) of switching cells (20a, 20b, 20c, 20d), wherein the individual control the various switching cells (20a, 20b, 20c, 20d) is effected as a function of a respective result of the thermal monitoring.

3. The semiconductor module (18) according to any one of claims 1 to 2, characterized in ^{¬ ¬} characterized in that a plurality of cooling circuits (51, 52) for cooling the switching cells (20a, 20b, 20c, 20d) is provided, wherein the cooling circuits (51 , 52) are arranged so reasonable that various cooling circuits (51, 52) ver ^¬ different groups (41, 42) of switching cells (20a, 20b, 20c, 20d) to cool.

4. The semiconductor module (18) according to claim 3, characterized in that the controller (5) is set up in order to control the ^different cooling circuits (51, 52) in such a way that an operating switching cell (20a, 20b, 20c, 20d) is cooled more than a non-operating switching cell (20a, 20b, 20c, 20d).

5. The semiconductor module (18) according to one of claims 1 to 4, characterized in ^¬ characterized in that at least some of the switching cells (20a, 20b, 20c, 20d) of the plurality of switching cells (20a, 20b, 20c, 20d) have different voltage strengths.

6. The semiconductor module (18) according to any one of claims 1 to 5, since ^¬ characterized in that different switching cells (20a, 20b, 20c, 20d) are controlled via different communication channels to ^¬ .

7. The semiconductor module (18) according to any one of claims 1 to 6, since ^¬ characterized by that various switching cells (20a, 20b, 20c, 20d) have different switching speeds based on ^¬ wise and / or in different semiconductor technologies.

8. The semiconductor module (18) according to any one of claims 1 to 7, character- ized in that not all, but at least one of the switching cells (20a, 20c) each have a fuse (22) is assigned, each of the fuses (22) in such a way is designed and connected to the associated switching cell (20a, 20c), that in case of overcurrent the fuse (22) associated switching cell (20a, 20c) the respective switching cell (20a, 20c) is functionally separated from the semiconductor module (18), and wherein the Control (5) is arranged such that in a normal operation of the semiconductor module (18) only Schaltzel ^¬ len (20a, 20c) are used, which is associated with a fuse (22), and only in the presence of a fault in the semiconductor module (18) a Switching cell (20b, 20d) is used without ^¬ orderly backup.

9. A method for operating a power electronics circuit with a semiconductor module (18) according to claim 1, wherein at ^¬ least temporarily different switching cells (20a, 20b, 20c, 20d) of the semiconductor module (18) are simultaneously driven with different control signals.

10. The method according to claim 8, characterized in that each group (41, 42) of switching cells (20a, 20b, 20c, 20d) is individually thermally monitored, wherein the individual control of the various switching cells (20a, 20b, 20c , 20d) depending on a respective result of the thermal monitoring.

11. The method according to any one of claims 8 to 10, character- ized in that the groups (41, 42) of switching cells

(20a, 20b, 20c, 20d) are operated alternately such that

in a first period only a first group (41) of

Switching cells (20a, 20b) is operated, while a second group (42) of switching cells (20c, 20d) is not operated in the first period,

- in the first period following the second time period only the second group (42) of switching cells (20c, 20d) will be ^¬ exaggerated, while the first group (41) of switching cells (20a, 20b) not in the second period is operated .

12. The method according to any one of claims 8 to 11, characterized in that a plurality of cooling circuits (51, 52) for cooling the switching cells (20a, 20b, 20c, 20d) is provided, wherein the cooling circuits (51, 52) arranged such in that different cooling circuits (51, 52) cool different groups (41, 42) of switching cells (20a, 20b, 20c, 20d), wherein an operating switching cell (20a, 20b, 20c, 20d) is cooled more than one not in operation be ^¬ sensitive switching cell (20a, 20b, 20c, 20d).

13. The method according to any one of claims 8 to 12, characterized in that the switching cells (20a, 20b, 20c, 20d) are driven so that either switching cells (20a, 20b, 20c, 20d) are in operation, their behavior on immunity optimized against cosmic radiation, or switching cells

(20a, 20b, 20c, 20d) are in operation, which are up to their maxi ^¬ paint withstand voltage usable.

14. The method according to any one of claims 8 to 13, character- ized in that not all, but at least one of

Switching cells (20a, 20c) each have a fuse (22) is zugeord ^¬ net, each of the fuses (22) designed in such a way and with the associated switching cell (20a, 20c) is connected, that at overcurrent load of the fuse (22) ordered switching cell (20a, 20c), the respective switching cell

(20a, 20c) operatively from the semiconductor module (18) is disconnected, and wherein the controller (5) is arranged such that in a normal operation of the semiconductor module (18) only Schaltzel ^¬ len (20a, 20c) are used, which added a fuse - is assigned, and only in the presence of a fault in the semiconductor ^¬ conductor module (18) a switching cell (20 b, 20 d) is used without associated backup.