Power converter, method and control device for detecting a short circuit in a power converter, electric axle drive and motor vehicle

Abstract

A power converter (100) comprises a first switch (110) and a second switch (120), a first output coupling device (115), a second output coupling device (125), and a transformer device (135). The first output coupling device (115) is configured to provide a first output coupling signal (118) representing a time course of a change in a first current flow through the first switch (110). The second output coupling device (125) is configured to provide a second output coupling signal (128) representing a time course of a change in a second current flow through the second switch (120).The transformer device (135) is configured to induce a magnetic field in a core (145) using the first output signal (118) and the second output signal (128), and to provide an evaluation signal (162) using the magnetic field, which represents a short circuit (180) in the converter (100).

Description

[0001] The present invention relates to a power converter, to a method and to a control device for detecting a short circuit in a power converter, to an electric axle drive and to a motor vehicle.

[0002] DE 10 2017 103 326 A1 discloses a method and a device for short-circuit detection in power semiconductor switches.

[0003] Against this background, the present invention provides an improved power converter, an improved method and an improved control device for detecting a short circuit in a power converter, an improved electric axle drive, and an improved motor vehicle according to the main claims. Advantageous embodiments emerge from the subclaims and the following description.

[0004] The advantages achievable with the approach presented here are, in particular, that a power converter is created in which a short circuit can be detected reliably and quickly.

[0005] A power converter comprises a first switch of a bridge circuit unit, a second switch of the bridge circuit unit, a first decoupling device, a second decoupling device, and a transformer device. The first switch is connected between a first supply voltage terminal and a tapping point, and the second switch is connected between a second supply voltage terminal and the tapping point. The first decoupling device is configured to provide a first decoupling signal representing a time profile of a change in a first current flow through the first switch. The first decoupling device is connected in series with the first switch between the first supply voltage terminal and the tapping point.The second decoupling device is designed to provide a second decoupling signal which represents a temporal profile of a change in a second current flow through the second switch. The second decoupling device is connected to the second switch in series between the second supply voltage connection and the tapping point. The transformer device has a core, a first coupling coil, a second coupling coil and an decoupling coil. The first coupling coil is connected to the first decoupling device in a signal-transmitting manner and is designed to induce a first magnetic field in the core using the first decoupling signal. The second coupling coil is connected to the second decoupling device in a signal-transmitting manner and is designed to induce a second magnetic field in the core using the second decoupling signal.The decoupling coil is designed to provide an evaluation signal that represents a short circuit in the power converter using an evaluation magnetic field resulting from the first magnetic field and the second magnetic field.

[0006] The power converter can be designed to convert a voltage applied between the supply voltage terminals, for example a direct voltage, into a different type of voltage, for example an alternating voltage. The power converter can also be designed as a converter to convert an alternating voltage into a different type of alternating voltage. For example, the power converter can be used to convert a battery voltage provided by a vehicle's battery into an operating voltage for operating a drive motor of the vehicle. For voltage conversion, the power converter can have a circuit known from known power converters. Accordingly, the bridge circuit unit can be designed as at least one half-bridge. The first switch can represent a high-side switch, or HSS for short, and the second switch can represent a low-side switch, or LSS for short, of the half-bridge.The bridge circuit unit can have further half-bridges, which can be shaped corresponding to the aforementioned half-bridge; for example, the bridge circuit unit can comprise three half-bridges. Using the decoupling devices integrated into the bridge circuit unit, a highly inductive short circuit can be detected. Therefore, the approach presented here can be used to detect a highly inductive short circuit. The transformer device can be designed corresponding to known transformer devices, wherein the core can be designed as an iron core. Optionally, the evaluation signal provided by the transformer device can be conditioned using an optional evaluation device and provided as a short-circuit signal, which can, for example, display more detailed information regarding the short circuit represented by the evaluation signal.The first coupling coil and the second coupling coil can be wound in opposite directions. This allows a deflection of the evaluation signal to be detected. Alternatively, the first coupling coil and the second coupling coil can be wound in the same direction. This allows the evaluation signal to be monitored for changes. Particularly advantageously, the first coupling coil and the second coupling coil have the same number of windings and / or the same inductance.

[0007] By using the decoupling devices in combination with the transformer device, a short circuit can be detected at the earliest possible moment, for example, by detecting an unusually rapid increase in current flowing through one of the switches. The resulting current rate of change can be referred to as di / dt. In the case of a low-inductance short circuit, the di / dt can be very high in the event of a fault compared to normal operation, allowing a generously dimensioned trip threshold to be defined. However, if a highly inductance short-circuit path occurs in the event of a fault, for example, outside a converter housing, the resulting current rate of change is low.In this case, the short-circuit current cannot flow through both switches, the high-voltage and low-voltage switches, but only through the switched-on switch, since the blocking switch can continue to block without failure. The approach presented here can detect such a highly inductive short-circuit fault early and quickly, allowing shutdown to be initiated. For this purpose, the decoupling devices can be arranged at positions within the bridge circuit unit suitable for detecting the resulting current rate of change.

[0008] The first decoupling device can, for example, be connected between the first switch and the tapping point. Alternatively, the first decoupling device can be connected between the first switch and the first supply voltage terminal. In this way, the first decoupling device can reliably detect a current change rate within a branch of the bridge circuit unit comprising the first switch.

[0009] The second decoupling device can be connected between the second switch and the tapping point. Alternatively, the second decoupling device can be connected between the second switch and the second supply voltage terminal. In this way, the first decoupling device can reliably detect a current change rate within a branch of the bridge circuit unit comprising the second switch.

[0010] The first decoupling device and the second decoupling device can each be configured as an inductor. This allows the rate of current change to be easily and reliably detected.

[0011] A first connection of the first decoupling device can be connected to a first input of the first coupling coil. Another first connection of the first decoupling device can be connected to a further first input of the first coupling coil. A second connection of the second decoupling device can be connected to a second input of the second coupling coil. Another second connection of the second decoupling device can be connected to a further second input of the second coupling coil. Thus, the coupling coils can reliably and quickly map current changes occurring at the decoupling devices in the form of magnetic fields induced in the core of the transformer device, which can superimpose themselves to form the evaluation magnetic field.In return, the output coil can easily and reliably convert the evaluation magnetic field running in the core into an evaluation signal that represents the evaluation magnetic field and thus the current changes occurring at the output devices.

[0012] The transformer device can have a further coupling-out coil, which can be configured to provide a further evaluation signal using the evaluation magnetic field resulting from the first magnetic field and the second magnetic field. The evaluation signal can represent the short circuit between the tapping point and the first supply voltage terminal in the power converter. The further evaluation signal can represent a further short circuit between the tapping point and the second supply voltage terminal in the power converter. In this way, the position of the short circuit and the further short circuit in the power converter can be reliably detected. For this purpose, the coupling-out coils can be wound in opposite directions to one another.

[0013] The power converter can have a comparator which can have a first input, a second input and an output. The comparator can be connected via the first input to a first terminal of the output coupling coil and via the second input to a reference voltage terminal. The comparator can be designed to provide a short-circuit signal indicating the short circuit using a differential voltage applied between the first input and the second input. The power converter can have a further comparator which can have a further first input, a further second input and a further output. The further comparator can be connected via the further first input to a further first terminal of the further output coupling coil and via the further second input to the reference voltage terminal.The further comparator can be configured to provide a further short-circuit signal indicating the further short circuit using a further differential voltage applied between the further first input and the further second input. Using the comparators, the evaluation signals can be prepared, for example, for use in a downstream signal processing device, for example, by comparing each of them with a reference voltage potential.

[0014] A second terminal of the output coil can be connected to a ground potential terminal. Another second terminal of the second output coil can be connected to the ground potential terminal. This allows both output coils to be connected to a common potential.

[0015] The power converter may have a control device that may be configured to provide switching signals for switching the switches to control inputs of the switches. Each of the switches may comprise a control input and a first contact and a second contact, wherein a current flow between the contacts may be controlled via the switching signal applied to the control input. Operation of the power converter may be controlled in a known manner via the control device.

[0016] The switches can be implemented as transistors, allowing the use of circuit elements typical of half-bridges.

[0017] A method for detecting a short circuit is provided for a power converter. The method comprises a step of providing, a step of inducing a first magnetic field, a step of inducing a second magnetic field, and a step of providing an evaluation signal. In the providing step, a first decoupling signal and a second decoupling signal are provided. The first decoupling signal represents a temporal profile of a change in a first current flow through the first switch, and the second decoupling signal represents a temporal profile of a change in a second current flow through the second switch. In the inducing step, at least one of the magnetic fields is induced into the core of the transformer device.In the providing step, the evaluation signal is provided using an evaluation magnetic field resulting from the first magnetic field and the magnetic fields. Such an embodiment also allows the advantages of the approach described here to be realized very efficiently.

[0018] An electric axle drive for a motor vehicle comprises an electric machine, a transmission device, and an embodiment of a power converter mentioned herein. Using the power converter, an electric current required to operate the electric machine can be provided. Using the transmission device, a torque provided by the electric machine can be converted into a drive torque for driving at least one wheel of the motor vehicle. The transmission device can have a gearbox for reducing the speed of the electric machine and optionally a differential.

[0019] Accordingly, a motor vehicle may comprise a said power converter and additionally or alternatively a said electric axle drive.

[0020] The invention is explained in more detail by way of example with reference to the accompanying drawings. They show: Fig. 1 a circuit diagram of an embodiment of a power converter; Fig. 2 a circuit diagram of an embodiment of a power converter; Fig. 3 a circuit diagram of an embodiment of a power converter; Fig. 4 a circuit diagram of an embodiment of a power converter; Fig. 5 is a flowchart of an embodiment of a method for detecting a short circuit in a power converter; and Fig. 6 a representation of an embodiment of a motor vehicle.

[0021] In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, whereby a repeated description of these elements is omitted.

[0022] Fig. 1 shows a circuit diagram of an exemplary embodiment of a power converter 100. The power converter 100 is designed, for example, to generate an alternating current from a direct current or an alternating current or three-phase current with a different frequency from an alternating current or a three-phase current. The power converter 100 is used, for example, in a motor vehicle to convert a battery voltage into the operating voltage required to operate an actuator.

[0023] For this purpose, the power converter 100 has at least one bridge circuit unit 105, wherein the bridge circuit unit 105 is designed, for example, as a half-bridge and has a first switch 110 and a second switch 120. The switches 110, 120 are designed, for example, as transistors and are connected to one another via a tapping point 130. More precisely, the first switch 110 is connected between a first supply voltage terminal 102 and the tapping point 130, and the second switch 120 is connected between a second supply voltage terminal 104 and the tapping point 130.

[0024] The power converter 100 further comprises a first decoupling device 115 for providing a first decoupling signal 118 and a second decoupling device 125 for providing a second decoupling signal 118. According to one embodiment, the decoupling devices 115, 125 are each designed as an inductor. Such an inductor can be designed, for example, as a dedicated element and / or as a parasitic element present in the circuit.

[0025] The first decoupling device 115 is connected in series with the first switch 110. More precisely, the first decoupling device 115 is connected in series with the first switch 110 between the first supply voltage terminal 102 and the tapping point 130. According to the exemplary embodiment shown here, the first decoupling device 115 is connected between the first switch 110 and the tapping point 130.

[0026] The second decoupling device 125 is connected in series with the second switch 120. More precisely, the second decoupling device 125 is connected in series with the second switch 120 between the second supply voltage terminal 104 and the tapping point 130. According to the exemplary embodiment shown here, the second decoupling device 125 is connected between the second switch 120 and the second supply voltage terminal 104.

[0027] The power converter 100 additionally has a transformer device 135. The transformer device 135 comprises a core 145, a first coupling coil 140, a second coupling coil 150, and an output coupling coil 160. According to one embodiment, the coupling coils 140, 150 are wound in opposite directions. According to an alternative embodiment, the coupling coils 140, 150 are wound in the same direction. The windings of the coupling coils 140, 150 and the output coupling coil 160 are wound around the core 145, which is designed as a magnetic core, for example, as a toroidal core.

[0028] The first coupling coil 140 is connected to the first decoupling device 115 in a signal-transmitting manner, and the second coupling coil 150 is connected to the second decoupling device 125 in a signal-transmitting manner.

[0029] According to one embodiment, a first terminal 116 of the first decoupling device 115 is connected to a first input 146 of the first coupling coil 140. Another first terminal 117 of the first decoupling device 115 is connected to a further first input 147 of the first coupling coil 140. According to a further embodiment, a second terminal 126 of the second decoupling device 125 is connected to a second input 156 of the second coupling coil 150. Another second terminal 127 of the second decoupling device 125 is connected to a further second input 157 of the second coupling coil 150.

[0030] According to one embodiment, the first coupling-out signal 118 represents a first electrical voltage drop across the first coupling-out device 115, and the second coupling-out signal 128 represents a second electrical voltage drop across the second coupling-out device 125. The first electrical voltage is applied to the first coupling-in coil 140, and the second electrical voltage is applied to the second coupling-in coil 150.

[0031] The power converter 100 optionally has a control device 170 and optionally an evaluation device 190. The control device 170 is designed to provide switching signals 172, 174 for switching the switches 110, 120 to control inputs of the switches 110, 120, via which a current flow through the switches 110, 120 can be controlled. For example, during operation of the power converter 100, a first switching signal 172 is provided to the control input of the first switch 110 to close the first switch 110, and a second switching signal 174 is provided to the control input of the second switch 120 to open the second switch 120, and vice versa. Thus, the first switch 110 and the second switch 120 are each alternately opened and closed, for example. For example, the second switch 120 is closed when the first switch 110 is open and vice versa, since otherwise a short circuit may occur in the bridge circuit unit 105.

[0032] During operation of the power converter 100, the current flows in the switches 110, 120 change. A temporal profile of the change in the first current flow through the first switch 110 is mapped using the first decoupling signal 118. The first decoupling device 115 is designed to provide the first decoupling signal 118 to the first coupling coil 140. Using the first decoupling signal 118, the first coupling coil 140 induces a first magnetic field in the core 145. A temporal profile of the change in the second current flow through the second switch 120 is mapped using the second decoupling signal 128. The second decoupling device 125 is designed to provide the second decoupling signal 128 to the second coupling coil 150. Using the second decoupling signal 128, the second coupling coil 150 induces a second magnetic field in the core 145.

[0033] The first magnetic field and the second magnetic field overlap and cause an evaluation magnetic field in the core 145. One of the magnetic fields may also be absent if no current flows through one of the output devices 115, 125.

[0034] The output coil 160 is configured to provide an electrical evaluation signal 162 when excited by the evaluation magnetic field. The evaluation signal 162 represents the occurrence of a short circuit 180 in the power converter 100, which influences a typical operating current flow through at least one of the output devices 115, 125. A resulting temporal change in a current flow through at least one of the output devices 115, 125 leads to a temporal change in the evaluation magnetic field, which indicates the short circuit 180. Optionally, the evaluation signal 162 is provided to the evaluation device 190. The evaluation device 190 is configured to provide a short-circuit signal 192 using the evaluation signal 162. For example, the evaluation device 190 is configured to amplify the evaluation signal 162 or to compare it with a threshold value in order to provide the short-circuit signal 192.

[0035] According to one embodiment, Fig. Figure 1 shows a possible implementation of the transformer-based evaluation of the di / dt signal of both switches 110, 120. The di / dt is coupled out via the common-source path.

[0036] In other words, the bridge circuit unit 105, which can also be referred to as a power electronic circuit for converting energy, has one or more half-bridges. Each of the half-bridges, corresponding to the half-bridges shown, has the first switch 110, which can also be referred to as the upper switch and / or high-side switch, and the second switch 120, which can also be referred to as the lower switch and / or low-side switch. According to one exemplary embodiment, these switches 110, 120 are arranged in series between the positive and negative poles of an intermediate voltage circuit. During normal operation, at most one of the switches 110, 120 is switched on at the same time, i.e., kept in the conductive state by its control. A typical fault is a so-called short circuit 180. This short circuit can also occur, for example, as a highly inductive short circuit 180.A previously insulating path becomes electrically conductive due to a fault. If such a fault, in series with a switched-on switch, for example, the second switch 120, creates a conductive connection between the positive and negative poles of the voltage intermediate circuit, an undesirably high current flow can occur through the fault location and the switched-on switch. This is potentially destructive and must be prevented.

[0037] The approach presented here is based on a transformer-based combination of the signal representing the temporal change in current flow di / dt through the first switch 110 and the temporal change in current flow di / dt through the second switch 120. The signals representing both current changes over time are wound in opposite directions onto the core 145 of the transformer device 135, here using the coupling coils 140, 150 as a primary winding according to one exemplary embodiment. A secondary winding, here in the form of the coupling coil 160, for example, couples out a voltage via the transformer device 135, designated as the evaluation signal 162. The evaluation signal 162 is also referred to as the detection signal.

[0038] The temporal change in the current flow of the first switch 110 impresses an induced voltage into the core 145 of the transformer device 135. If the current causing the temporal change in the current flow flows through both the first switch 110 and the second switch 120, an induced voltage in the opposite direction is simultaneously impressed into the core 145 of the transformer device 135. Due to the opposite sign, the contributions of the induced voltages cancel each other out. No voltage is output on the secondary winding, here the output coil 160, and no short circuit is detected.

[0039] According to one embodiment, a highly inductive short circuit 180 is characterized in that it occurs externally and does not flow through both switches 110, 120 simultaneously. If, for example, the short-circuit current flows through the second switch 120 because the first switch 110 is blocked and the external short circuit 180 occurs via the first switch 110, no di / dt signal from the first switch 110 is impressed into the core 145 of the transformer device 135. The impressed induction voltage of the second switch 120 is not compensated by any further signal, so that a voltage is induced in the secondary winding, which can be detected as a short-circuit signal 192.

[0040] The transformer evaluation of the output signals 118, 128 ensures galvanic isolation, so that the method for transmitting the di / dt can be selected as desired.

[0041] Furthermore, due to the galvanic isolation, it is possible to detect the output signals 118, 128 at any location, so that the short-circuit information can be read separately from multiple functional units without separate signal transmission. This method ensures that a low-inductance short circuit and / or a high-inductance short circuit 180 can be detected.

[0042] A short circuit detected in this way can be directly identified as being caused externally and leads to the assumption that both switches 110, 120 are intact despite the short circuit fault.

[0043] Fig. 2 shows a circuit diagram of an embodiment of a power converter 100. The power converter 100 is similar or corresponds to the power converter from Fig. 1, except that the coupling devices 115, 125 are arranged differently. In other words, Fig. 2, that the potential-free, transformer-based evaluation allows the di / dt signal to be coupled out, for example, in the drain path.

[0044] According to one embodiment, the first decoupling device 115 is connected between the first supply voltage terminal 102 and the first switch 110. The second decoupling device 125 is connected, for example, between the tapping point 130 and the second switch 120.

[0045] Apart from that, the functionality for detecting the short circuit 180 corresponds to that based on Fig. 1 described functionality.

[0046] The following described Fig. 3 and Fig. 4 show a variant for detecting the position of the short circuit 180. Since the short circuit 180 can be read out at various functional elements of the circuit, the information about the switched-on switch of the switches 110, 120 is not necessarily available. Fig. 3 and Fig. 4, it can be identified whether the short circuit 180 is present across the first switch 110 or the second switch 120.

[0047] Fig. 3 shows a circuit diagram of an embodiment of a power converter 100. The power converter 100 is similar or corresponds to the power converter from Fig. 2, except that the power converter 100 optionally has a comparator 300 and optionally a further comparator 310 and that the transformer device 135 has a further decoupling coil 360.

[0048] The additional output coil 360 is also wound around the core 145. According to one embodiment, the windings of the output coils 160, 360 are wound in opposite directions. Using the two output coils 160, 360, it is possible to determine, on the one hand, that the short circuit 180 is occurring, and, on the other hand, whether the short circuit is occurring at the first switch 110 or the second switch 120. Alternatively, the windings of the output coils 160, 360 are wound in the same direction.

[0049] The output coils 160, 360 are designed, for example, to provide evaluation signals 162, 362 using the evaluation magnetic field. The evaluation signal 162 represents, for example, the short circuit 180 between the tapping point 130 and the first supply voltage connection 102 in the power converter 100. The further evaluation signal 362 represents, for example, a further short circuit between the tapping point 130 and the second supply voltage connection 104 in the power converter 100, as is the case, for example, in Fig. 4 is shown.

[0050] According to one embodiment, a second terminal 368 of the output coupling coil 160 and another second terminal 364 of the further output coupling coil 360 are connected to a ground potential terminal 330.

[0051] The comparator 300 is connected, for example, to the output coupling coil 160 and a reference voltage terminal 320. More specifically, the comparator 300 has a first input 302, a second input 304, and an output 306. The comparator 300 is connected via the first input 302 to a first terminal 366 of the output coupling coil 160 and via the second input 304 to the reference voltage terminal 320.

[0052] The comparator 300 is designed to provide a short-circuit signal 392 using a differential voltage applied to the first input 302 and the second input 304, which represents, by way of example, the short circuit 180 between the tapping point 130 and the first supply voltage terminal 102.

[0053] The further comparator 310 is connected, for example, to the further output coupling coil 360 and the reference voltage terminal 320. More specifically, the further comparator 310 has a further first input 312, a further second input 314, and a further output 316. The further comparator 310 is connected via the further first input 312 to a further first terminal 365 of the further output coupling coil 360 and via the further second input 314 to the reference voltage terminal 320.

[0054] The further comparator 310 is designed to provide a further short-circuit signal 382 using a differential voltage applied to the further first input 312 and the further second input 314, which represents, by way of example, the further short-circuit between the tapping point 130 and the second supply voltage terminal 104.

[0055] Fig. 4 shows a circuit diagram of an embodiment of a power converter 100. The power converter 100 is similar or corresponds to the power converter from Fig. 3, except that in Fig. 4 shows the further short circuit 480 between the tapping point 130 and the second supply voltage terminal 104. The further short circuit 480 is therefore present across the second switch 120.

[0056] Due to the two secondary windings, it is possible to switch safely between the position of the Fig. 4 shown further short circuit 480 and the position of the Fig. 3 shown short circuit can be distinguished.

[0057] Fig. 5 shows a flowchart of an embodiment of a method 500 for detecting a short circuit in a power converter. The power converter has a first switch and a second switch of a bridge circuit unit. The first switch is connected between a first supply voltage terminal and a tapping point, and the second switch is connected between a second supply voltage terminal and the tapping point. The power converter is similar to or corresponds to the power converter from one of the figures described above.

[0058] The method 500 comprises a step 505 of providing, a step 510 of inducing a first magnetic field, a step 515 of inducing a second magnetic field and a step 520 of providing an evaluation signal.

[0059] In step 505 of providing, a first decoupling signal and a second decoupling signal are provided. The first decoupling signal represents a temporal profile of a change in a first current flow through the first switch, and the second decoupling signal represents a temporal profile of a change in a second current flow through the second switch.

[0060] In step 510 of inducing the first magnetic field, the first magnetic field is induced into a core of a transformer device. Step 510 is performed using a first coupling coil and the first coupling signal.

[0061] In step 515 of inducing the second magnetic field, the second magnetic field is induced in the core of the transformer device. Step 515 is performed using a second coupling coil and the second coupling signal. The first coupling coil and the second coupling coil are wound in opposite directions to each other. It is not necessary to wind the coupling coils in opposite directions. The windings can also be co-rotated, so that a deflection of the evaluation signal is not detected, but rather the evaluation signal is monitored for a change.

[0062] In step 520 of providing, the evaluation signal is provided using an evaluation magnetic field resulting from the first magnetic field and the second magnetic field. This step is performed using a decoupling coil of the transformer device, with the evaluation signal representing the short circuit in the power converter.

[0063] Fig.6 shows an illustration of an embodiment of a motor vehicle 600. The motor vehicle 600 has an electric axle drive 610 with an electric machine 605, as described, for example, with reference to the preceding figures. Electrical energy for operating the electric machine 605 is provided by a power supply device 602, for example a battery. For example, the power supply device 602 provides a direct current, which is converted into an alternating current, for example a three-phase alternating current, using a power converter 100 of the transmission device and is supplied to the electric machine 605. A shaft driven by the electric machine 605 is coupled directly or using a transmission device 606 to at least one wheel 608 of the motor vehicle 600.Thus, the motor vehicle 600 can be propelled using the electric machine 605. According to one embodiment, the electric axle drive 610 comprises a housing in which the power converter 100, the electric machine 605, and the transmission device 606 are arranged in an integrated manner. Reference symbol 100 power converters 102 first supply voltage connection 104 second supply voltage connection 105 Bridge circuit unit 110 first switch 115 first decoupling device 116 first connection of the first decoupling device 117 further first connection of the first decoupling device 118 first decoupling signal 120 second switch 125 second decoupling device 126 second connection of the second decoupling device 127 further second connection of the second decoupling device 128 second decoupling signal 130 tapping point 135 Transformer equipment 140 first coupling coil 145 core 146 first input of the first coupling coil 147 further first input of the first coupling coil 150 second coupling coil 156 second input of the second coupling coil 157 further second input of the second coupling coil 160 output coil 162 evaluation signal 170 Control device 172 first switching signal 174 second switching signal 180 short circuit 190 Evaluation device 192 Short circuit signal 300 Comparator 302 first input of the comparator 304 second input of the comparator 306 Output of the comparator 310 additional comparator 312 further first input of the further comparator 314 further second input of the further comparator 316 further output of the further comparator 320 Reference voltage connection 330 Ground potential connection 360 additional output coil 362 additional evaluation signal 364 further second connection of the further output coil 365 further first connection of the further output coil 366 first connection of the output coil 368 second connection of the output coil 382 further short circuit signal 392 Short circuit signal 500 methods for detecting a short circuit in a power converter 505 Deployment Step 510 Step of induction 515 Step of induction 520 Step of Deployment 600 motor vehicles 602 Energy supply facility 605 electric machine 606 Gearbox device 608 wheels 610 electric axle drive QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 103 326 A1

[0002]

Claims

[1] Power converter (100) having the following features: a first switch (110) of a bridge circuit unit (105), wherein the first switch (110) is connected between a first supply voltage terminal (102) and a tapping point (130); a first decoupling device (115) which is designed to provide a first decoupling signal (118) which represents a temporal profile of a change in a first current flow through the first switch (110), wherein the first decoupling device (115) is connected to the first switch (110) in series between the first supply voltage terminal (102) and the tapping point (130); a second switch (120) of the bridge circuit unit (105), wherein the second switch (120) is connected between a second supply voltage terminal (104) and the tapping point (130); a second decoupling device (125) configured to provide a second decoupling signal (128) representing a temporal profile of a change in a second current flow through the second switch (120), wherein the second decoupling device (125) is connected to the second switch (120) in series between the second supply voltage terminal (104) and the tapping point (130); and a transformer device (135) having a core (145), a first coupling coil (140), a second coupling coil (150) and a decoupling coil (160), wherein the first coupling coil (140) is connected to the first decoupling device (115) in a signal-transmitting manner and is designed to induce a first magnetic field into the core (145) using the first decoupling signal (118), wherein the second coupling coil (150) is connected to the second coupling device (125) in a signal-transmitting manner and is designed to induce a second magnetic field into the core (145) using the second coupling signal (128), and wherein the coupling coil (160) is designed to provide an evaluation signal (162) representing a short circuit (180) in the power converter (100) using an evaluation magnetic field resulting from the first magnetic field and the second magnetic field. [2] Power converter (100) according to claim 1, wherein the first decoupling device (115) is connected between the first switch (110) and the tapping point (130) or wherein the first decoupling device (115) is connected between the first switch (110) and the first supply voltage terminal (102). [3] Power converter (100) according to one of the preceding claims, wherein the second decoupling device (125) is connected between the second switch (120) and the tapping point (130) or wherein the second decoupling device (125) is connected between the second switch (120) and the second supply voltage terminal (104). [4] Power converter (100) according to one of the preceding claims, wherein the first decoupling device (115) and the second decoupling device (125) are each formed as an inductance. [5] Power converter (100) according to one of the preceding claims, wherein a first terminal (116) of the first decoupling device (115) is connected to a first input (146) of the first coupling coil (140) and wherein a further first terminal (117) of the first decoupling device (115) is connected to a further first input (147) of the first coupling coil (140), wherein a second terminal (126) of the second decoupling device (125) is connected to a second input (156) of the second coupling coil (150) and wherein a further second terminal (127) of the second decoupling device (125) is connected to a further second input (157) of the second coupling coil (150). [6] Power converter (100) according to one of the preceding claims, wherein the transformer device (135) has a further coupling-out coil (360) which is designed to provide a further evaluation signal (362) using the evaluation magnetic field resulting from the first magnetic field and the second magnetic field, wherein the evaluation signal (162) represents the short circuit between the tapping point (130) and the first supply voltage terminal (102) in the power converter (100) and wherein the further evaluation signal (362) represents a further short circuit (480) between the tapping point (130) and the second supply voltage terminal (104) in the power converter (100). [7] Power converter (100) according to one of the preceding claims, comprising a comparator (300) having a first input (302), a second input (304) and an output (306), wherein the comparator (300) is connected via the first input (302) to a first terminal (366) of the output coil (160) and via the second input (304) to a reference voltage terminal (320), wherein the comparator (300) is designed to provide a short-circuit signal (392) indicating the short circuit using a differential voltage applied between the first input (302) and the second input (304), comprising a further comparator (310) having a further first input (312), a further second input (314) and a further output (316),wherein the further comparator (310) is connected via the further first input (312) to a further first terminal (365) of the further output coil (360) and via the further second input (314) to the reference voltage terminal (320), wherein the further comparator (310) is designed to provide a further short-circuit signal (382) indicating the further short-circuit (480) using a further differential voltage applied between the further first input (312) and the further second input (314). [8] Method (500) for detecting a short circuit in a power converter (100) having a first switch (110) and a second switch (120) of a bridge circuit unit (105), wherein the first switch (110) is connected between a first supply voltage terminal (102) and a tapping point (130), wherein the second switch (120) is connected between a second supply voltage terminal (104) and the tapping point (130), wherein the method (500) comprises the following steps: Providing (505) a first decoupling signal (118) and a second decoupling signal (128), wherein the first decoupling signal (118) represents a temporal profile of a change in a first current flow through the first switch (110), wherein the second decoupling signal (128) represents the temporal profile of a change in the second current flow through the second switch (120); Inducing (510) a first magnetic field into a core (145) of a transformer device (135) using a first coupling coil (140) and the first coupling signal (118); Inducing (515) a second magnetic field into the core (145) of the transformer device (135) using a second coupling coil (150) and the second coupling signal (128); and Providing (520) an evaluation signal (162) using an evaluation magnetic field resulting from the first magnetic field and the second magnetic field, using a coupling-out coil (160) of the transformer device (135), wherein the evaluation signal (162) represents the short circuit (180) in the power converter (100). [9] Electric axle drive (610) for a motor vehicle (600) with at least one electric machine (605), a transmission device (606) and a power converter (100), characterized bythat the power converter (100) is designed according to one of claims 1 to 10. [10] Motor vehicle (600) comprising an electric axle drive (610) according to claim 13 and / or a power converter (100) according to one of claims 1 to 10.

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