Control device for semiconductor switches of an inverter output stage

Abstract

The invention relates to a control device (1) for semiconductor switches (4a,5a,4b,5b,4c,5c) of an inverter output stage (2), comprising a processor (12) and a respective driver circuit (6a,7a,6b,7b,6c,7c) provided for each semiconductor switch (4a,5a,4b,5b,4c,5c) of the inverter output stage (2), wherein the processor (12) is designed to transmit parameters of a phase current during a switching process of one of the semiconductor switches (4a,5a,4b,5b,4c,5c) of the inverter output stage (2) to the corresponding driver circuit (6a,7a,6b,7b,6c,7c) of the semiconductor switch (4a,5a,4b,5b,4c,5c) via a communication interface (14,15), and the driver circuit (6a,7a,6b,7b,6c,7c) of the semiconductor switch (4a,5a,4b,5b,4c,5c) has a computing unit (23) which is designed to compute the present sinusoidal curve of the phase current for the switching process of the semiconductor switch (4a,5a,4b,5b,4c,5c) on the basis of the parameters transmitted by the processor (12). The driver circuit (6a,7a,6b,7b,6c,7c) of the semiconductor switch (4a,5a,4b,5b,4c,5c) has a current profile storage device (25) that is designed to select a current profile, which is stored in the storage device, on the basis of the sinusoidal phase current curve computed by the computing unit (23) of the driver circuit (6a,7a,6b,7b,6c,7c) and / or on the basis of a voltage and / or on the basis of a temperature and provide same to the driver circuit (6a,7a,6b,7b,6c,7c) of the semiconductor switch (4a,5a,4b,5b,4c,5c) in order to carry out the switching process in the semiconductor switch (4a,5a,4b,5b,4c,5c).

Description

[0001] Description

[0002] title

[0003] Control device for semiconductor switches of an inverter power stage

[0004] The present invention relates to a control device for semiconductor switches of an inverter output stage and a method for switching semiconductor switches of an inverter output stage.

[0005] State of the art

[0006] Electric and hybrid vehicles often have power electronic circuit components in the drive system between the traction battery and the electric motor, which are typically designed as voltage source converters. A DC link serves as a coupling element between the traction battery and an inverter, which can be controlled to transfer electrical power from the DC link to the electric motor.

[0007] Inverters can have an inverter output stage, which can be designed as a full-bridge circuit with a number of bridge branches, each with two semiconductor switches. The semiconductor switches of the bridge branches connected to a first output terminal of the DC link are each referred to as high-side (HS) switches, and the semiconductor switches of the bridge branches connected to the second output terminal of the DC link are each referred to as low-side (LS) switches. Each semiconductor switch of the inverter output stage receives a driver signal from a driver circuit. The inverter output stage has at least one half-bridge, which comprises series-connected semiconductor switches with associated driver circuits. Typically, the inverter output stage has three half-bridges, each with two series-connected semiconductor switches.

[0008] Conventional inverters can use voltage-controlled gate driver ASICs to control the semiconductor switches of the inverter output stage, with a constant gate current being set by the gate resistance of the semiconductor switch. Alternatively, current source drivers with programmable current profiles are used, but the current profiles are selected exclusively via hardware feedback (Vgs, Vds) on the high-voltage side. There is no communication with a PC or processor during the control of the semiconductor switches of the inverter output stage.

[0009] Programmable current sources can be used in the gate driver ASICs to control an inverter output stage (B6 bridge). Various current profiles for switching the power semiconductor switches of the inverter output stage on and off are stored in the gate driver. Depending on the operating point, the current profiles can be selected by the processor via a communication interface before each switching operation. However, the selection of the current profiles via the communication interface, which depends on the operating point and particularly on the phase current, is relatively slow. The switching time is also controlled via a separate digital input pin (PWM). In addition, the control of the switching time and communication or data transmission via the communication interface are asynchronous to one another, which leads to an additional error in the control of the power semiconductor switches of the inverter output stage.

[0010] The changes in the DC link voltage and the temperature in the power module are significantly slower compared to the transmission time frame used by the communication interface. Therefore, both variables can be transmitted by the processor in a timely manner within the transmission time frame of the communication interface. The phase current, on the other hand, changes significantly faster and therefore the inrush or inrush current profile must be quickly adjusted to the desired switching time.

[0011] Disclosure of the invention

[0012] The present invention provides a control device according to claim 1 and a method for switching semiconductor switches of an inverter output stage according to claim 11 as well as a drive system according to claim 12.

[0013] Preferred further training is the subject of the subclaims.

[0014] According to a first aspect, the present invention provides a control device for semiconductor switches of an inverter output stage, comprising a processor and a driver circuit provided for each semiconductor switch of the inverter output stage, wherein the processor is designed to transmit parameters of a phase current during a switching operation of one of the semiconductor switches of the inverter output stage to the associated driver circuit of the semiconductor switch via a communication interface, wherein the driver circuit of the semiconductor switch has a calculation unit which is designed to calculate the current sinusoidal phase current profile of the phase current for the switching operation of the semiconductor switch depending on the parameters transmitted by the processor, and wherein the driver circuit of the semiconductor switch has a current profile memory which is designed toto select a current profile stored therein depending on the sinusoidal phase current curve of the phase current calculated by the calculation unit of the driver circuit and / or depending on a voltage and / or depending on a temperature and to provide it to the driver circuit of the semiconductor switch for carrying out the switching operation in the semiconductor switch.

[0015] According to a further aspect, the invention provides a method for switching a semiconductor switch of an inverter output stage by an associated driver circuit, comprising the steps of: providing parameters of a phase current provided during a switching operation of the semiconductor switch of the inverter output stage to the associated driver circuit of the semiconductor switch by a processor;

[0016] Calculating a current sinusoidal phase current curve of the phase current for the switching operation of the semiconductor switch as a function of the parameters provided by the processor by a calculation unit of the driver circuit of the semiconductor switch; and

[0017] Selecting a current profile stored in a current profile memory of the driver circuit of the semiconductor switch as a function of the sinusoidal phase current curve of the phase current calculated by the calculation unit of the driver circuit for carrying out the switching process in the semiconductor switch and / or as a function of a voltage and / or as a function of a temperature.

[0018] According to a further aspect, the invention provides a drive system for an n-phase electrical machine, where n > 1, with an inverter output stage having at least one half-bridge comprising series-connected semiconductor switches with associated driver circuits, wherein the inverter output stage is fed with electrical energy from an intermediate circuit capacitor of a high-voltage circuit and is designed to generate an n-phase supply voltage for the electrical machine, and with a control device for the semiconductor switches of the inverter output stage, which has a processor and the driver circuit provided for each semiconductor switch of the inverter output stage, wherein the processor of the control device is designed toParameters of a phase current during a switching operation of one of the semiconductor switches of the inverter output stage of the associated driver circuit of the semiconductor switch via a communication interface, wherein the driver circuit of the semiconductor switch has a calculation unit which is designed to calculate the current sinusoidal phase current profile of the phase current for the switching operation of the semiconductor switch as a function of the parameters transmitted by the processor of the control device, and wherein the driver circuit of the semiconductor switch has a current profile memory which is designed toto select a current profile stored therein depending on the sinusoidal phase current curve of the phase current calculated by the calculation unit of the driver circuit and / or depending on a voltage and / or depending on a temperature and to provide it to the driver circuit of the semiconductor switch for carrying out the switching operation in the semiconductor switch.

[0019] Advantages of the invention

[0020] A basic idea of ​​the invention is to implement the current profile selection at the current switching time using the hardware in the driver circuit. The current profile selection takes place extremely quickly in real time.

[0021] The sinusoidal waveform of the phase current is calculated reliably and flexibly by a calculation unit of the driver circuit from the information transmitted from the processor to the driver circuit via the communication interface.

[0022] According to one embodiment of the control device, the parameters of the phase current transmitted from the processor to the driver circuit comprise a peak value of the phase current, a frequency of the phase current and a phase position of the phase current.

[0023] This allows the temporal phase current curve of the desired or requested phase current to be calculated precisely.

[0024] According to one embodiment of the control device, the current profile memory of the driver circuit has a first one-dimensional look-up table designed to provide a first index for the phase current dependence for different amplitude ranges of the phase current curve calculated by the calculation unit of the driver circuit. According to one embodiment of the control device, the current profile memory of the driver circuit has a second multi-dimensional look-up table designed to select an address of the current profile memory depending on the first index for the phase current dependence provided by the first look-up table and depending on at least one further index, wherein a current profile for switching on the associated semiconductor switch and / or a current profile for switching off the associated semiconductor switch by the driver circuit is stored at the selected address.

[0025] This allows other relevant influencing factors to be flexibly taken into account when selecting the current profile.

[0026] According to one embodiment of the control device, the further indices for selecting the address of the current profile memory comprise a voltage index and / or a temperature index.

[0027] According to one embodiment of the control device, the further indices for selecting the address of the current profile memory are transmitted from the processor to the driver circuit of the semiconductor switch via the communication interface.

[0028] This allows the control device to react quickly and reliably to changes in relevant influencing factors.

[0029] According to one embodiment of the control device, the voltage index indicates the electrical voltage of a high-voltage circuit which is connected to the inverter output stage for its voltage supply.

[0030] The current electrical voltage of the high-voltage circuit is an important influencing factor for the selection of the current profile. According to one embodiment of the control device, the temperature index indicates the temperature of the semiconductor switch which is switched by the driver circuit.

[0031] The temperature of the semiconductor switch is also an important factor in the selection of the current profile.

[0032] According to one embodiment of the control device, further current profiles for special cases are stored in the current profile memory of the driver circuit.

[0033] This allows the control device to be configured for different types of applications and errors and offers a higher level of safety when special operating conditions and error cases occur.

[0034] According to one embodiment of the control device, the current profiles stored in the current profile memory of the driver circuit for special cases have at least one current profile for an occurring communication error, at least one current profile for an occurring short circuit and / or at least one current profile for an occurring overcurrent.

[0035] This ensures safety when various and potentially frequently occurring errors occur.

[0036] Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

[0037] Short description of the drawings

[0038] The present invention is explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawing.

[0039] 1 shows a schematic block diagram of a possible embodiment of the control device according to the invention;

[0040] Fig.2 is a flow chart illustrating a possible embodiment of the method according to the invention;

[0041] Fig.3 is a block diagram of a possible implementation of a driver circuit with a calculation unit integrated therein;

[0042] Fig. 4 is a block diagram of a possible implementation of a current profile memory within a driver circuit.

[0043] In the figures, the same reference symbols denote the same or functionally identical elements.

[0044] As shown in Fig. 1, according to a first aspect, the present invention provides a control device 1 for semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c of an inverter output stage 2. In one possible embodiment, the inverter output stage 2 has three half-bridges 3a, 3b, 3c, wherein each half-bridge of the inverter output stage 2 comprises two series-connected semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c. The semiconductor switches 4a, 4b, 4c form the high-side switches, which are connected to the positive terminal (T+) of the intermediate circuit, and the semiconductor switches 5a, 5b, 5c form the low-side switches, which are connected to the negative terminal (T-) of the intermediate circuit. The control device 1 has a processor 12 and a driver circuit 6a, 7a, 6b, 7b, 6c, 7c provided for each semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c of the inverter output stage 2.The processor 12 of the control device 1 is designed to transmit various parameters of a phase current during a switching operation of one of the semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c of the inverter output stage 2 to the associated driver circuit 6a, 7a, 6b, 7b, 6c, 7c of the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c via a communication interface 14, 15. In one possible embodiment, this communication interface 14, 15 is formed by a serial UART interface. In one embodiment, the processor 12 is located on a low voltage side (LV - Low Voltage) for controlling a low voltage primary logic within the driver circuit 6a, 7a, 6b, 7b, 6c, 7c, which is galvanically isolated from a high voltage secondary logic on a high voltage side (HV - High Voltage) within the driver circuit 6a, 7a, 6b, 7b, 6c, 7c by an isolation barrier.

[0045] The driver circuits 6a, 7a, 6b, 7b, 6c, 7c of the semiconductor switches

[0046] 4a, 5a, 4b, 5b, 4c, 5c each have a calculation circuit 10a, 11a, 10b, 11c, 10c, 11c integrated therein with a calculation unit 23. Fig. 3 shows a possible implementation of the calculation circuit 10a, 11a, 10b, 11c, 10c, 11c with the calculation unit 23 contained therein. The calculation unit 23 is designed to calculate the current sinusoidal phase current curve of the phase current for the switching operation of the respective semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c in real time, depending on the parameters received from the processor 12 via the communication interface 14, 15. The calculation units 23, which are each contained in a calculation circuit 10a, 11a, 10b, 11c, 10c, 11c of an ASIC driver circuit 6a, 7a, 6b, 7b, 6c, 7c, are preferably each formed by an application-specific hardware calculation unit which executes calculations at high calculation speed.

[0047] In one embodiment of the control device 1, the parameters of the phase current Iph transmitted from the processor 12 to the driver circuit 6a, 7a, 6b, 7b, 6c, 7c via the communication interface 14, 15 include a peak value of the phase current, a frequency of the phase current Iph, and a phase position of the phase current Iph. These parameters can be transmitted within a data frame or data packet and temporarily stored in a UART register 24 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c, as shown in Fig. 3. The parameters stored in the UART register 24 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c can be updated or renewed each time a communication connection is successfully established via the communication interface 14, 15. For example, the peak value of the phase current comprises 7 bits, the phase position of the phase current comprises 10 bits and the frequency of the phase current comprises 10 bits, as shown in Fig.3.The parameter values ​​temporarily stored in register 24 are read out and used by the calculation unit 23 to calculate the current sinusoidal phase current profile of the phase current Ipha for the switching operation of the respective semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c. A PWM signal can serve as a trigger for the calculation, which is applied via a control line 16, 17 from the processor 12 to the calculation unit 23 of the calculation circuit 10a, 11a, 10b, 11c, 10c, 11c of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c. The calculated sinusoidal phase current profile of the phase current for the switching operation of the respective semiconductor switch is schematically illustrated as a time signal in the top left of Fig. 3.

[0048] The calculation circuit 10a, 11a, 10b, 11c, 10c, 11c, as shown in Fig. 3, can have logic 27 that monitors the UART start frame and performs CRC checks. This logic 27 generates enable and reset signals for counters, which supply counter values ​​to a multiplexer 28, which, on the output side, supplies a selected counter value to the calculation unit 23 of the calculation circuit 10a, 11a, 10b, 11c, 10c, 11c. The logic 27 also supplies the selection signal, which is applied to the control input of the multiplexer 28 and selects the time counter value (t-UART) used in the current calculation by the calculation unit 23.

[0049] The following three pieces of information regarding the phase current Ipha can be transmitted by the processor 12 via the communication interface 14, 15 (UART), for example in a 100ps time frame, in a possible embodiment of the respective driver circuit 6a, 7a, 6b, 7b, 6c, 7c: the frequency w , the current peak value and the phase <j>of the phase alternating current.

[0050] Using this information, the calculation unit 23 of the calculation circuit 10a, 11a, 10b, 11c, 10c, 11c of the respective driver circuit 6a, 7a, 6b, 7b, 6c, 7c calculates the sinusoidal phase current Ipha independently and preferably in real time:

[0051] Ipha = I * sin( <j)UART + w*(t-tUART)) Die Treiberschaltungen 6a, 7a, 6b, 7b, 6c, 7c der Halbleiterschalter

[0052] 4a, 5a, 4b, 5b, 4c, 5c each further comprise a current profile memory 25, which is preferably formed by a RAM memory. The current profile memory 25 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c is designed to select a current profile stored in the current profile memory 25 depending on the phase current Ipha calculated by the calculation unit 23 of the corresponding driver circuit 6a, 7a, 6b, 7b, 6c, 7c and to assign it to the driver circuit 6a, 7a, 6b, 7b, 6c, 7c of the respective semiconductor switch.

[0053] 4a, 5a, 4b, 5b, 4c, 5c for performing the switching operation in the associated semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c. In one possible embodiment, the current profile memory 25 comprises a RAM memory, as schematically illustrated in Fig. 4.

[0054] In one possible implementation, the current profile memory 25 contains a first stored look-up table (LUT1) and a second stored look-up table (LUT2).

[0055] In one embodiment of the control device 1, the respective current profile memory 25, which is provided in each of the driver circuits 6a, 7a, 6b, 7b, 6c, 7c, has a first one-dimensional look-up table (LUT1) which is designed to provide a first index (Idxlpha) for the phase current dependence for different amplitude ranges of the phase current curve Ipha calculated by the calculation unit 23 of the calculation circuit 10a, 11a, 10b, 11c, 10c, 11c of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c.

[0056] In one embodiment of the control device 1, the current profile memory 25, which is provided in the driver circuit 6a, 7a, 6b, 7b, 6c, 7c, has a second multidimensional look-up table (LUT2) designed to select an address of the current profile memory 25 depending on the first index (Idxlpha) for the phase current dependence provided by the first look-up table (LUT1) and depending on at least one further index. A current profile for switching on the associated semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c and / or a current profile for switching off the associated semiconductor switch by the driver circuit 6a, 7a, 6b, 7b, 6c, 7c is stored at the selected address.

[0057] In the exemplary implementation shown in Fig. 4, the sinusoidal phase current Ipha calculated by the calculation unit 23 of the calculation circuit 10a, 11a, 10b, 11c, 10c, 11c is divided into several ranges, for example, 16 ranges. For example, the calculated phase current Ipha comprises 7 bits, corresponding to 128 amplitude levels.

[0058] In the first 1-D look-up table (LUT1), the ranges for the phase current Ipha are defined via UART communication interface 14,15 during initialization.

[0059] The current phase current Ipha, calculated by the calculation unit 23 of the calculation circuit 10a, 11a, 10b, 11c, 10c, 11c, serves as the input for the first look-up table (LUT1) of the current profile memory 25. The output of the 1-D look-up table (LUT1) provides the 4-bit index idxIPha for the phase current dependency, which, together with the intermediate circuit voltage Uzk and the temperature T of the power module, serves as the input for the second 3-D look-up table (LUT2) of the current profile memory 25.

[0060] In one possible embodiment of the control device 1, the additional indices for selecting the address of the current profile memory 25 comprise a voltage index (UdxUTnet) and / or a temperature index (IdxTemp). In one embodiment of the control device 1, the additional indices for selecting the address of the current profile memory 25 are transmitted from the processor 12 via the communication interface 14, 15 to the driver circuit 6a, 7a, 6b, 7b, 6c, 7c of the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c.

[0061] In one embodiment of the control device 1, the voltage index (UdxUTnet) indicates the electrical voltage of a high-voltage circuit connected to the inverter output stage 2 for its power supply. This high-voltage circuit is the intermediate circuit of the inverter. In one embodiment of the control device 1, the temperature index (Idxtemp) indicates the temperature T of the respective semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c, which is switched by the driver circuit 6a, 7a, 6b, 7b, 6c, 7c.

[0062] The information regarding the current intermediate circuit voltage (IdxUTnet) and the information regarding the temperature T of the circuit breaker (IdxTemp) are transmitted from the processor 12 to the calculation unit 23 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c

[0063] A number N of current profiles is stored in the 3D lookup table (LUT2) in such a way that they can be independently selected by the ASIC or the driver circuit 6a, 7a, 6b, 7b, 6c, 7c according to the operating point depending on the phase current, the intermediate circuit voltage Uzk and the temperature T of the power module at the switching time.

[0064] The selection of a current profile is carried out for both the switch-on time and the switch-off time of the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c, for example a MOSFET.

[0065] The intermediate circuit voltage Uzk of the intermediate circuit or high-voltage circuit can be detected by an HV voltage detection unit 18 of the inverter output stage 2. Furthermore, temperature sensors 19, 20 can be provided, which detect the temperature T of the semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c of the inverter output stage 2 and report it to the processor 12, as shown in Fig. 1.

[0066] In the current profile memory 25 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c, for example, N=124 current profiles are transmitted from the processor 12 to the respective driver circuit 6a, 7a, 6b, 7b, 6c, 7c via the UART communication interface 14, 15 during each initialization. Each current profile consists of a current profile for the switch-on process (ON) and a current profile for the switch-off process (OFF), as shown in Fig. 4. The current profiles specify the shape of the driver signals TS that are applied to the control input 8a, 9a, 8b, 9b, 8c, 9c of the respective semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c of the inverter output stage 2 during the respective switching process. The current profile numbers (index) of the N=124 current profiles are stored in the 3-D look-up table (LUT2) of the current profile memory 25 of the driver circuits 6a, 7a, 6b, 7b, 6c, 7c. The current profiles are also assigned by processor 12.

[0067] The calculated phase current Ipha (e.g., 7 bits) is used as input for the 1-D lookup table (LUT1). The output of the 1-D lookup table (LUT2) provides the index for the phase current idxIPha (e.g., 4 bits). The index for the intermediate circuit voltage idxUTnet (e.g., 3 bits) and the index for the measured temperature T of the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c IdxUTnet (e.g., 2 bits) are sent directly from the processor 12 to the driver circuits 6a, 7a, 6b, 7b, 6c, 7c via the UART communication interface 14, 15.

[0068] The three indices Idxipha (4 bits), IdxUTnet (3 bits), and IdxTemp (2 bits) form an address that serves as input for the 3-D look-up table (LUT2), as shown in Fig. 4. The 3-D look-up table LUT2 is also implemented in the current profile memory 25 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c.

[0069] The output of the 3-D look-up table (LUT2) provides the address idxCP (7 bits) of the selected turn-on or turn-off current profile, which is then made available to the current source driver by the current profile memory 25.

[0070] In one embodiment of the control device 1, further current profiles for special cases are stored in the current profile memory 25 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c. The current profiles for special cases stored in the current profile memory 25 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c preferably include at least one current profile for a communication error, at least one current profile for a short circuit, and / or at least one current profile for an overcurrent.

[0071] For example, five gate current profiles are provided for special cases, the selection of which is performed by the gate driver ASIC. For example, 128 current profiles are stored for each turn-on and turn-off process, as shown in Fig. 4. A current profile is provided as a fallback level in the event of a timeout or communication error (CRC protection). For other error cases, four special current profiles for short circuits / overcurrents are stored in the current profile memory 25 of the driver circuits 6a, 7a, 6b, 7b, 6c, 7c.

[0072] The inverter output stage 2 preferably forms part of an inverter. The inverter output stage 2 has at least one half-bridge comprising series-connected semiconductor switches with associated driver circuits. As shown in Fig. 1, the inverter output stage 2 in one possible embodiment comprises three half-bridges 3a, 3b, 3c, wherein each half-bridge of the inverter output stage 2 comprises two series-connected semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c. The number of half-bridges can vary in different embodiments. The semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c are formed in one possible embodiment by transistors, in particular field-effect transistors, or IGBTs.In one possible embodiment, the semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c are each IGBTs (Insulated Gate Bipolar Transistors). However, it is equally possible to provide other semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c in a corresponding form, for example in the form of JFETs (Junction Field-Effect Transistors) or MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors), in particular also SiC power transistors. If the semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c have IGBT switches, it can also be provided to connect a diode (not shown in Fig. 1 for reasons of clarity) in antiparallel to each of the IGBT switches.

[0073] The control device 1 further comprises the processor 12, which is connected via an interface to the associated driver circuits 6a, 7a, 6b, 7b, 6c, 7c of the inverter output stage 2. Each of the six semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c of the inverter output stage 2 has a control input 8a, 9a, 8b, 9b, 8c, 9c, which is designed to receive a driver signal TS from the associated driver circuit 6a, 7a, 6b, 7b, 6c, 7c of the inverter output stage 2.

[0074] In one embodiment of the control device 1, each half-bridge

[0075] 3a, 3b, 3c of the inverter output stage 2 each have two semiconductor switches 4a, 5a, 4b, 5b, 4c, 5c connected in series with one another, which are designed to supply a sinusoidal phase current Iph for an electrical load connected thereto at a connection node 13a, 13b, 13c during normal operation of the inverter output stage 2. The connection nodes 13a, 13b, 13c are connected via lines 21a, 21b, 21c to output terminals 22a, 22b, 22c of the inverter output stage 2, as shown in Fig. 1. The connected electrical load can comprise an inductive load, in particular a winding of an electric motor.

[0076] The half-bridges 3a, 3b, and 3c of the inverter output stage 2 are connected in parallel between a positive terminal T+ and a negative terminal T- of a high-voltage circuit. High-voltage semiconductor switches 4a, 4b, and 4c are connected to the positive terminal T+, and low-voltage semiconductor switches 5a, 5b, and 5c are connected to the negative terminal T- of the high-voltage circuit.

[0077] In one possible embodiment, the communication interface 14, 15 is formed by a UART interface. The driver circuits 6a, 7a, 6b, 7b, 6c, 7c can be formed by ASICs in one possible implementation.

[0078] The ASIC driver circuit 6a, 7a, 6b, 7b, 6c, 7c is provided with information via the UART interface 14, 15, from which the ASIC driver circuit 6a, 7a, 6b, 7b, 6c, 7c can independently determine the current phase current Ipha for the switching operation. The calculation unit 23 of the ASIC driver circuit 6a, 7a, 6b, 7b, 6c, 7c calculates the sinusoidal waveform of the phase current from the peak value of the phase current, the frequency omega, and the phase position, preferably in real time. The information on the current intermediate circuit voltage Uzk and the temperature T of the power semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c can be transmitted from the processor 12 to the ASIC driver circuit 6a, 7a, 6b, 7b, 6c, 7c.

[0079] A number of, for example, N=124 current profiles are used in the 3D lookup

[0080] The current profiles are stored in the table (LUT2) of the current profile memory 25 in such a way that they are independently selected by the ASIC driver circuit 6a, 7a, 6b, 7b, 6c, 7c depending on the phase current, the intermediate circuit voltage Uzk, and the temperature T of the power module at the switching time. The selection of the correct current profile by the ASIC driver circuit 6a, 7a, 6b, 7b, 6c, 7c is significantly faster and more precise than with a conventional software solution. Implementing the calculations in the ASIC driver circuit 6a, 7a, 6b, 7b, 6c, 7c also avoids extremely high resource requirements in the processor 12.

[0081] Fig. 2 shows a simple flow diagram illustrating a possible embodiment of the method according to the invention.

[0082] The method for switching a semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c of an inverter output stage 2 by an associated driver circuit 6a, 7a, 6b, 7b, 6c, 7c essentially comprises three main steps S1, S2, S3.

[0083] In a first step S1, parameters of a phase current provided during a switching operation of the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c of the inverter output stage 2 are provided to the associated driver circuit 6a, 7a, 6b, 7b, 6c, 7c of the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c by the processor 12 of the control device 1.

[0084] In a second step S2, a current sinusoidal phase current curve of the phase current Ipha for the switching process of the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c is calculated as a function of the parameters provided by the processor 12 by a calculation unit 23 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c of the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c.

[0085] In a third step S3, a current profile stored in a current profile memory 25 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c of the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c is selected as a function of the sinusoidal phase current curve of the phase current calculated by the calculation unit 23 of the driver circuit 6a, 7a, 6b, 7b, 6c, 7c for performing the switching operation in the semiconductor switch 4a, 5a, 4b, 5b, 4c, 5c. Additionally, the stored current profile can be selected as a function of a voltage and / or a temperature.

[0086] The control device 1 can be programmed with various gate current profiles for charging and discharging the power transistors 4a, 5a, 4b, 5b, 4c, 5c. The selection of optimal gate charging and discharging profiles for the actual operating state of the inverter during runtime is supported.

[0087] The gate current profiles allow adaptation to different inverter operating conditions (e.g., temperature, DC link voltage, phase current) or fault conditions (overcurrent, safe state) based on the information provided by the processor 12.

[0088] On the HV side, no external gate resistors, AMCL components, safe-state logic, or ADC are required. This allows for a significant reduction in external components and thus in board space requirements.< / j>

Claims

Patent claims 1. Control device (1) for semiconductor switches (4a, 5a, 4b, 5b, 4c, 5c) of an inverter output stage (2) with a processor (12) and with a driver circuit (6a, 7a, 6b, 7b, 6c, 7c) provided for each semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) of the inverter output stage (2), wherein the processor (12) is designed to transmit parameters of a phase current during a switching operation of one of the semiconductor switches (4a, 5a, 4b, 5b, 4c, 5c) of the inverter output stage (2) to the associated driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) via a communication interface (14,15), wherein the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) has a calculation unit (23) which is designed toto calculate the current sinusoidal phase current profile of the phase current for the switching process of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) as a function of the parameters transmitted by the processor (12), and wherein the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) has a current profile memory (25) which is designed to select a current profile stored therein as a function of the sinusoidal phase current profile of the phase current calculated by the calculation unit (23) of the driver circuit (6a, 7a, 6b, 7b, 6c, 7c), and / or as a function of a voltage and / or as a function of a temperature, and to the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) for carrying out the switching operation in the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c)., 2. Control device according to claim 1, wherein the parameters of the phase current transmitted from the processor (12) to the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) comprise a peak value of the phase current, a frequency of the phase current and a phase position of the phase current.

3. Control device according to claim 1 or 2, wherein the current profile memory (25) of the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) has a first one-dimensional look-up table (LUT1) which is designed to provide a first index (Idxlpha) for the phase current dependence for different amplitude ranges of the phase current curve calculated by the calculation unit (23) of the driver circuit (6a, 7a, 6b, 7b, 6c, 7c).

4. Control device according to claim 3, wherein the current profile memory (25) of the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) has a second multidimensional look-up table (LUT2) which is designed to select an address of the current profile memory (25) as a function of the first index (IdxPha) for the phase current dependence provided by the first look-up table (LUT1) and as a function of at least one further index, wherein a current profile for switching on the associated semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) and / or a current profile for switching off the associated semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) by the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) is stored at the selected address.

5. Control device according to claim 4, wherein the further indices for selecting the address of the current profile memory (25) comprise a voltage index (IdxUTnet) and / or a temperature index (IdxTemp).

6. Control device according to claim 4 or 5, wherein the further indices for selecting the address of the current profile memory (25) are transmitted from the processor (12) via the communication interface (14) to the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c).

7. Control device according to claim 5 or 6, wherein the voltage index (IdxUTnet) indicates the electrical voltage of a high-voltage circuit which is connected to the inverter output stage (2) for its voltage supply.

8. Control device according to claim 5 or 6, wherein the temperature index (IdxTemp) indicates the temperature of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) which is switched by the driver circuit (6a, 7a, 6b, 7b, 6c, 7c).

9. Control device according to one of claims 1 to 8, wherein further current profiles for special cases are stored in the current profile memory (25) of the driver circuit (6a, 7a, 6b, 7b, 6c, 7c).

10. Control device according to claim 9, wherein the current profiles stored in the current profile memory (25) of the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) for special cases have at least one current profile for an occurring communication error, at least one current profile for an occurring short circuit and / or at least one current profile for an occurring overcurrent.

11. Method for switching a semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) of an inverter output stage (2) by an associated driver circuit (6a, 7a, 6b, 7b, 6c, 7c), comprising the steps: Providing (S1) parameters of a phase current provided during a switching operation of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) of the inverter output stage (2) to the associated driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) by a processor (12); Calculating (S2) a current sinusoidal phase current waveform of the phase current for the switching process of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) depending on the parameters provided by the processor (12) by a calculation unit (23) of the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c); and Selecting (S3) a current profile stored in a current profile memory (25) of the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) as a function of the sinusoidal current profile calculated by the calculation unit (23) of the driver circuit (6a, 7a, 6b, 7b, 6c, 7c). Phase current profile of the phase current and / or as a function of a voltage and / or as a function of a temperature for carrying out the switching process in the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c).

12. Drive system for an n-phase electrical machine, where n > 1, with an inverter output stage (2) which has at least one half-bridge (3a, 3b, 3c) which comprises series-connected semiconductor switches (4a, 5a, 4b, 5b, 4c, 5c) with associated driver circuits (6a, 7a, 6b, 7b, 6c, 7c), wherein the inverter output stage (2) is fed with electrical energy from an intermediate circuit capacitor of a high-voltage circuit and is designed to generate an n-phase supply voltage for the electrical machine, and with a control device (1) for the semiconductor switches (4a, 5a, 4b, 5b, 4c, 5c) of the inverter output stage (2), which control device has a processor (12) and which for each semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) of the inverter output stage (2) has a respective driver circuit (6a, 7a, 6b, 7b, 6c, 7c), wherein the processor (12) is designed to determine parameters of a phase current during a switching operation of one of the semiconductor switches (4a, 5a,4b, 5b, 4c, 5c) of the inverter output stage (2) of the associated driver circuit, (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) via a communication interface (14, 15), wherein the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) has a calculation unit (23) which is designed to calculate the current sinusoidal phase current curve of the phase current for the switching process of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) as a function of the parameters transmitted by the processor (12), and wherein the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) has a current profile memory (25) which is designed to, as a function of the current profile generated by the calculation unit (23) of the driver circuit (6a, 7a, 6b, 7b, 6c,7c) calculated sinusoidal phase current curve of the phase current and / or as a function of a voltage and / or as a function of a temperature, and to provide said current profile to the driver circuit (6a, 7a, 6b, 7b, 6c, 7c) of the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c) for carrying out the switching operation in the semiconductor switch (4a, 5a, 4b, 5b, 4c, 5c).

Images