Power module for a converter with twisted signal pin pairs for control signal routing, converter, electric axle drive and vehicle

Abstract

Power module (10) for a converter for use in an at least partially electrified vehicle, wherein the power module (10) has one or more power switches which are switchable for converting an input current into an output current and are mounted on a circuit carrier (26), wherein the power module (10) has a printed circuit board (29) which is equipped with components of a control device (30a-b) for generating control signals, wherein the power module (10) has a plurality of signal pins (20, 20a-b, 22, 22a-b) for transmitting the control signals to the power switches, wherein the signal pins (20, 20a-b, 22, 22a-b) are electrically connected on the one hand to the circuit carrier (26) and on the other hand to the printed circuit board (29), wherein the signal pins (20, 20a-b, 22, 22a-b) have one or more signal pin pairs (24, 24a-b), each consisting of at least two signal pins (20,20a-b,22,22a-b) twisted together, characterized in that the signal pin pairs (24,24a-b) are each at least partially covered with an electromagnetic shield.

Description

[0001] The invention relates to a power module for a converter for use in an at least partially electrified vehicle, in particular a battery-electric vehicle, a fuel cell vehicle, or a hybrid vehicle. Furthermore, the invention relates to an electric axle drive with such a power module and a vehicle with such an electric axle drive.

[0002] Purely electric vehicles and hybrid vehicles are known in the prior art, which are powered exclusively or with support by one or more electric motors as drive units. Such electrified vehicles typically use a rechargeable vehicle drive battery that provides a direct current (DC voltage) to power the electric motors. To this end, the DC voltage is converted into an alternating current (AC voltage) by a DC / AC inverter in order to supply the electric motors with a multiphase alternating current (AC current).

[0003] The core component of such converters is a power electronics unit comprising a plurality of power switches. These power switches are interconnected to create a half-bridge arrangement comprising one or more half-bridges. Each half-bridge consists of a high-side device and a low-side device, each of which has one or more parallel-connected power switches. Each power switch comprises a positive-pole current electrode (e.g., drain electrode), a negative-pole current electrode (e.g., source electrode), and a control electrode (e.g., gate electrode).

[0004] For voltage conversion, the power switches are switched in a targeted manner. To switch a power switch, control signals are impressed on the control electrode of the power switch. The control signals are carried by a control path that connects a control device to the control electrode. In the power modules known from the prior art, signal pins are used for this purpose. Each of these pins is electrically connected to a control electrode on one side and to a circuit board containing the components of the control device on the other.

[0005] Twisted or spring-loaded connection elements for semiconductor components are known from JP H02-178 954 A (forms the generic term), DE 37 34 067 A1, and DE 102 31 219 C1. DE10 2016 206 233 A1 describes the use of power semiconductor modules in vehicles with electric axle drive for partially electrified vehicles.

[0006] However, the known power modules have the disadvantage that the design of the signal pin arrangement results in high coupling inductance between the control path (e.g., gate loop) and the load path (e.g., source loop), so that electromagnetic fields induced by the time-varying load current easily couple into the control path. This leads to parasitic effects, such as parasitic turn-on (PTO) and exceeding the safety operating areas of the power switches, particularly during switching operations of the power switches, and poses a high risk of impairment for the entire converter.

[0007] It is an object of the invention to provide a power module for a converter in which the disadvantage described above is at least partially eliminated.

[0008] This object is achieved according to the invention by the power module, the converter, the electric axle drive, and the vehicle according to the independent patent claims. Advantageous embodiments and further developments of the invention are set forth in the dependent patent claims.

[0009] The invention relates to a power module for a converter for operating an electric axle drive in an at least partially electrified vehicle, such as an electric vehicle and / or hybrid vehicle. The converter is, for example, a DC / AC inverter. In this case, the input current is a DC current provided by a DC voltage source, such as a rechargeable vehicle drive battery, and the output current is an AC current with multiple phase currents. Alternatively, the converter is designed as an AC / DC rectifier, for example to recharge the vehicle drive battery. For this purpose, an AC input voltage provided by an AC voltage supply (e.g., charging station) is converted via the AC / DC rectifier into a DC output voltage, which can then be fed to the vehicle drive battery.Alternatively, the converter is used as a DC / DC converter to adapt a DC input voltage to the DC operating voltage (nominal voltage) of the vehicle drive battery, for example, to increase it from 400V to 800V.

[0010] The power module comprises at least one power switch, preferably a plurality of power switches, for feeding the input current and for generating the output current based on the fed-in input current by switching the power switches. In the case of a multi-phase DC / AC inverter, the entire power electronics comprises a plurality of (for example, three) phases, each having a half-bridge. Each phase or half-bridge serves to convert the fed-in DC current into a phase current by switching the associated power switches, wherein the plurality of phase currents generated thereon are phase-shifted from one another and are each fed into a winding of the electric motor to supply current to the electric axle drive. The half-bridges each have a high side with a higher electrical potential and a low side with a lower electrical potential.In the case of a multi-phase AC / DC rectifier, the entire power electronics also comprises several (for example three) phases, with the power switches being switched to cancel the phase offsets between the phase currents of the injected AC current, resulting in a DC current at the output.

[0011] Various configurations of the power module are conceivable. For example, the power module can be designed as a so-called half-bridge module, which has a module highside and a module lowside, each with a single power switch or several power switches connected in parallel. In this case, each phase of the entire converter can comprise a single half-bridge module or several half-bridge modules connected in parallel. In the former case, the highside of the phase is formed by the module highside and the lowside of the phase is formed by the module lowside of the single half-bridge module. In the latter case, the highside of the phase is formed by a parallel connection of the module highsides of the parallel-connected half-bridge modules, with the lowside of the phase being formed by a parallel connection of the module lowsides of the parallel-connected half-bridge modules. Alternatively, the power module can comprise only one module highside or one module lowside.The case where the power module has a single power switch occurs when the module highside or the module lowside comprises only a single power switch. Alternatively, the power module can refer to the entirety of the parallel-connected half-bridge modules of a phase, or to the entirety of the parallel-connected module highsides or module lowsides of a phase.

[0012] The power switches are preferably transistors, such as MOSFETs, HEMTs and / or IGBTs. The semiconductor material underlying the power switches is preferably silicon or a so-called wide bandgap semiconductor (WBG), such as silicon carbide, gallium nitride or gallium oxide. The power switches are also preferably mounted on a circuit carrier, e.g. a printed circuit board (PCB), or a multilayer ceramic substrate, at least partially coated with a metal (e.g. copper), such as direct-bonded copper (DBC), direct-plated copper (DPC) or active metal bonding (AMB). The power switches are preferably arranged on a first metal layer of the circuit carrier, with a second metal layer of the circuit carrier being connected to a cooler. An insulation layer is preferably arranged between the first metal layer and the second metal layer.

[0013] The power switches each comprise a positive-pole or controlled current electrode (e.g. drain electrode), a negative-pole or ground-potential current electrode (e.g. source electrode), and a control electrode (e.g. gate electrode). The positive-pole current electrode and the negative-pole current electrode, together with the semiconductor structure located between them, form a load path of the respective power switch, through which the load current flows when the power switch is open (conductive). The ground potential is preferably provided by a metallic layer of the circuit carrier on which the power switches are arranged. To feed the input current (load current) into the power module or to draw the output current from the power module, a plurality of power terminals are provided in the power module, which are electrically connected to the current electrodes of the respective power switch.The power connections are connected to busbars to enable current flow to other components of the converter, such as a DC link capacitor in the case of a DC / AC inverter, or an external unit such as the windings of the electric motor to be powered. Current flow within the power module, for example, between the individual power switches, is achieved using multiple power lines, which are, for example, designed as wire bonds or integrated into a lead frame.

[0014] Additionally, the power module comprises a circuit board equipped with electrical and / or electronic components of a control device for generating control signals for switching the power switches. The circuit board can be designed as a printed circuit board, in particular a driver board. The circuit board preferably extends in a plane substantially parallel to the circuit carrier.

[0015] According to the invention, the power module has a plurality of signal pins for transmitting the control signals to the power switches. The signal pins are electrically connected to the circuit carrier on the one hand and to the printed circuit board on the other, wherein the signal pins comprise one or more signal pin pairs, each consisting of two signal pins twisted together. Two signal pins run in each signal pin pair, each representing a signal line, wherein the signal lines are twisted together or twisted against each other and wound around each other in a helical manner. A first signal pin of the respective signal pin pair can be electrically connected to a control electrode (e.g. gate electrode) of a corresponding power switch, wherein a second signal pin of the respective signal pin pair can be electrically connected to a negative-pole current electrode (e.g. source electrode) of the corresponding power switch.

[0016] One or more of the signal pins can be designed to transmit control signals to so-called auxiliary switches, i.e. semiconductor switches that are not part of a high side or low side in a half-bridge. Examples of auxiliary switches include active Miller clamping (AMC) auxiliary switches, short-circuit protection auxiliary switches, temperature sensor auxiliary switches, or current sensor auxiliary switches. However, the present invention is not limited to these. Analogous to power switches, in this case a first signal pin of a signal pin pair is electrically connected to a control electrode (e.g. gate electrode) of the auxiliary switch, wherein a second signal pin of the signal pin pair is electrically connected to a negative-pole current electrode (e.g. source electrode) of the auxiliary switch.

[0017] By twisting the signal pin pairs or twisted pair cables (TPC), interference from external electromagnetic fields can largely cancel each other out. This advantageously minimizes crosstalk between the paired signal lines, thus achieving common-mode rejection. This can reduce the gate loop inductance. Therefore, twisted signal pin pairs, especially compared to parallel signal lines, provide better protection against electrical and magnetic interference.

[0018] Additionally, the twisted-pair arrangement of the signal pins, which are preferably provided as cables, allows for a flexible shape of the signal pin pairs, which allows tolerance compensation with increased freedom of movement when attaching the signal pins to the power module. Alternatively, the signal pin pairs can be formed from an electrically conductive solid material. The signal pin pairs can each be connected to the circuit board and / or the circuit carrier by means of a plug connection, a soldered connection (e.g., thermode soldering), a welded connection (e.g., ultrasonic welding), or a metallic connection. However, the connection method is not limited to the examples mentioned above.

[0019] According to one embodiment, the signal pin pairs are each covered, at least in sections, with an electrically insulating coating. This measure ensures reliable electrical insulation of the signal pins and protection against external influences such as mechanical shocks. Each signal pin pair can be assigned an insulating coating in a one-to-one correspondence. Alternatively, multiple signal pin pairs can be covered by the same insulating coating.

[0020] According to the invention, the signal pin pairs are each at least partially covered with an electromagnetic shield. This measure provides additional protection against electromagnetic interference in addition to the twisted arrangement of the signal pin pairs. The electromagnetic shield can be integrated, for example, as a metallic inner layer (e.g., a copper layer) within the electrically insulating coating. A metallic inner layer refers, for example, to a metallic sheathing of the signal pin pair.

[0021] The invention further relates to a converter with a power module according to one of the embodiments described here, a corresponding electric axle drive comprising such a converter, and a vehicle with such an electric axle drive. As described above, the converter can have a DC / AC inverter, an AC / DC rectifier, or a DC / DC converter, whereby the invention is not limited to these purely exemplary converter designs, but can generally be used in semiconductor-based power electronics. This results in the advantages already described in connection with the power module according to the invention also for the converter according to the invention, the electric axle drive according to the invention, and the vehicle according to the invention.

[0022] The invention is explained below by way of example with reference to embodiments shown in the figures.

[0023] They show: Fig. 1 a schematic representation of the power module with signal pin pairs each consisting of two twisted signal pins according to an embodiment in a side view; Fig. 2 shows a schematic representation of the power module according to a further embodiment in a perspective view, wherein the signal pin pairs are each covered with an electrically insulating coating; Fig. 3 a further schematic representation of the power module according to the further embodiment of Fig. 2 in a perspective view.

[0024] Identical objects, functional units, and comparable components are designated by the same reference symbols throughout the figures. These objects, functional units, and comparable components are identical in terms of their technical features, unless explicitly or implicitly stated otherwise in the description.

[0025] Fig. 1 shows a schematic representation of a power module 10 according to one embodiment in a side view. The power module 10 for a converter for operating an electric axle drive in an at least partially electrified vehicle, such as an electric vehicle and / or hybrid vehicle. The converter can be designed as a DC / AC inverter, AC / DC rectifier, or DC / DC converter.

[0026] The power module 10 comprises at least one power switch, preferably a plurality of power switches, for feeding in an input current and for generating an output current based on the fed-in input current by switching the power switches. In the case of a multi-phase DC / AC inverter, the entire power electronics comprises a plurality of (for example, three) phases, each having a half-bridge. Each phase or half-bridge serves to convert the fed-in DC current into a phase current by switching the associated power switches, wherein the plurality of phase currents generated thereon are phase-shifted from one another and are each fed into a winding of the electric motor to supply current to the electric axle drive. The half-bridges each have a high side with a higher electrical potential and a low side with a lower electrical potential.In the case of a multi-phase AC / DC rectifier, the entire power electronics also comprises several (for example three) phases, with the power switches being switched to cancel the phase offsets between the phase currents of the injected AC current, resulting in a DC current at the output.

[0027] Various configurations of the power module 10 are conceivable. For example, the power module 10 can be designed as a so-called half-bridge module, which has a module highside and a module lowside, each with a single power switch or multiple power switches connected in parallel. In this case, each phase of the entire converter can comprise a single half-bridge module or multiple half-bridge modules connected in parallel. In the former case, the highside of the phase is formed by the module highside and the lowside of the phase is formed by the module lowside of the single half-bridge module. In the latter case, the highside of the phase is formed by a parallel connection of the module highsides of the parallel-connected half-bridge modules, with the lowside of the phase being formed by a parallel connection of the module lowsides of the parallel-connected half-bridge modules. Alternatively, the power module 10 can comprise only one module highside or one module lowside.The case in which the power module 10 has a single power switch occurs when the module highside or the module lowside comprises only a single power switch. Alternatively, the power module 10 can refer to the entirety of the parallel-connected half-bridge modules of a phase, or to the entirety of the parallel-connected module highsides or module lowsides of a phase.

[0028] The power switches are preferably transistors, such as MOSFETs, HEMTs, and / or IGBTs. The semiconductor material underlying the power switches is preferably silicon or a so-called wide bandgap semiconductor (WBC), such as silicon carbide, gallium nitride, or gallium oxide. The power switches are also preferably mounted on a circuit carrier 26 (see Fig. 2-3), e.g., a printed circuit board (PCB), or a multilayer ceramic substrate, at least partially coated with a metal (e.g., copper), such as direct-bonded copper (DBC), direct-plated copper (DPC), or active metal bonding (AMB). Preferably, the power switches are arranged on a first metal layer of the circuit carrier 26, wherein a second metal layer of the circuit carrier 26 is connected to a cooler 25 or a top side 252 of the cooler 25 by means of a thermally conductive layer 27, such as a sintered layer. An insulation layer is preferably arranged between the first metal layer and the second metal layer. The cooler 25 can, as in Fig. 1 purely exemplary and shown schematically, have a pin-fin structure in order to increase the surface area that can be exposed to the cooling medium (e.g. water) and thus increase the cooling performance.

[0029] The power switches each comprise a positive-pole or controlled current electrode (e.g., drain electrode), a negative-pole or ground-potential current electrode (e.g., source electrode), and a control electrode (e.g., gate electrode). The positive-pole current electrode and the negative-pole current electrode, together with the semiconductor structure located therebetween, form a load path of the respective power switch, through which the load current flows when the power switch is in an open (conductive) state. The ground potential is preferably provided by a metallic layer of the circuit carrier 29 on which the power switches are arranged. To feed the input current (load current) into the power module 10 or to draw the output current from the power module 10, a plurality of power terminals 14, 16, 18 are provided in the power module 10, which are electrically connected to the current electrodes of the respective power switch.The power terminals 14, 16, and 18 are connected to busbars 13, 15, and 17 to enable current flow to other components of the converter, such as an intermediate circuit capacitor in the case of a DC / AC inverter, or an external unit such as the windings of the electric motor to be powered. Current flow within the power module 10, for example, between the individual power switches, is achieved using multiple power lines, which may be wire-bonded or integrated into a lead frame.

[0030] The circuit breakers are, as in Fig. 1, preferably covered with a current-insulating material. The protective covering 11 is formed, for example, by encapsulating or overmolding the circuit breaker together with the circuit carrier 26 and the power terminals 14, 16, 18, wherein a contact surface of the respective power terminals 14, 16, 18, accessible from the outside of the protective covering or protective encapsulation compound or protective overmolding, is exposed from the current-insulating material.

[0031] In addition, the power module 10 comprises a circuit board 29, which is equipped with electrical and / or electronic components of a control device 30a-b for generating control signals for switching the power switches. The circuit board 29 can be designed as a circuit board, in particular a driver board. Preferably, the circuit board 29 extends in a plane substantially parallel to the circuit carrier 26. As shown in Fig. 1, a first control device 30a is assigned to the high side of a half-bridge, while a second control device 30b is assigned to the low side of the half-bridge. The first control device 30a is therefore configured to control the high-side power switches, while the second control device 30b is configured to control the low-side power switches.

[0032] The power module 10 has several signal pins 20a-b, 22a-b for transmitting the control signals to the power switches. The signal pins 20a-b, 22a-b are electrically connected to the circuit carrier on the one hand and to the printed circuit board on the other.

[0033] As in Fig. 1, the signal pins form one or more signal pin pairs 24a-b, each consisting of two signal pins 20a, 22a; 20b, 22b twisted together. The signal pin pairs are each at least partially covered with an electromagnetic shield, which in Fig. 1 and Fig. 3 is not shown to indicate the twisting. In a first signal pin pair 24a, which is assigned to the high side, there run two signal pins 20a, 22a, each representing a signal line, wherein the signal lines are twisted together or twisted against each other and wound around each other in a helical manner. A first signal pin 20a of the first signal pin pair 24a is electrically connected to a control electrode (e.g. gate electrode) of a high-side power switch, wherein a second signal pin 22a of the first signal pin pair 24a is electrically connected to a negative-pole current electrode (e.g. source electrode) of the high-side power switch. Analogously, in a second signal pin pair 24b, which is assigned to the low side, there run two signal pins 20b, 22b, each representing a signal line, wherein the signal lines are twisted together or twisted against each other and wound around each other in a helical manner.A first signal pin 20b of the second signal pin pair 24b is electrically connected to a control electrode (e.g., gate electrode) of a low-side power switch, while a second signal pin 22b of the second signal pin pair 24b is electrically connected to a negative-pole current electrode (e.g., source electrode) of the low-side power switch. The signal pins 20a-b, 22a-b are each individually provided with an insulating layer, ensuring potential isolation between the twisted signal pins 20a-b, 22a-b.

[0034] By twisting the signal pin pairs 24a-b, interference from external electromagnetic fields can largely cancel each other out. This advantageously minimizes crosstalk between the paired signal lines, thus achieving common-mode rejection. Therefore, twisted signal pin pairs 24a-b provide better protection against electrical and magnetic interference, particularly compared to parallel signal lines.

[0035] Fig. 2-3 shows the power module 10 according to a further embodiment. Here, several signal pins 20, 22 are twisted in pairs and form several signal pin pairs 24. At least one signal pin pair 24 can be designed to transmit control signals to so-called auxiliary switches, i.e., semiconductor switches that are not part of a high side or low side in a half-bridge. Examples of auxiliary switches include active Miller clamping (ACM) auxiliary switches, short-circuit protection auxiliary switches, temperature sensor auxiliary switches, and current sensor auxiliary switches. However, the present invention is not limited to these. Analogous to power switches, in this case a first signal pin 20 of the at least one signal pin pair 24 is electrically connected to a control electrode (e.g., gate electrode) of the auxiliary switch, wherein a second signal pin 22 of the at least one signal pin pair 24 is connected to a negative-pole current electrode (e.g.,source electrode) of the auxiliary switch.

[0036] As in Fig. 2, the signal pin pairs 24 are each covered, at least in sections, with an electrically insulating coating 23. This measure ensures reliable electrical insulation of the signal pins and protection against external influences such as mechanical shocks. Each signal pin pair 24 can be assigned an insulating coating in a one-to-one correspondence. Alternatively, although not shown here, multiple signal pin pairs 24 can be covered by the same insulating coating 23.

[0037] The signal pin pairs 24 are each at least partially covered with an electromagnetic shield. This measure provides additional protection against electromagnetic interference in addition to the twisted arrangement of the signal pin pairs 24. The electromagnetic shield can be integrated, for example, as a metallic inner layer (e.g., a copper layer) within the electrically insulating coating 23. Reference symbol 10 Power module 11 current-insulating protective covering (protective overmolding) 13 positive-pole DC power rail 14 positive-pin DC power connection 15 negative-pole DC power rail 16 negative-pole DC power connection 17 AC busbar 18 AC power connection 20, 20a-b first signal pin 22, 22a-b first signal pin 23 electrically insulating coating 24, 24a-b signal pin pair 25 coolers 252 top 26 circuit boards (PCBs) 262 top 27 thermally conductive layer (sintered layer) 29 Circuit board (driver board) 30a-b control device

Claims

[1] Power module (10) for a converter for use in an at least partially electrified vehicle, wherein the power module (10) has one or more power switches which are switchable for converting an input current into an output current and are mounted on a circuit carrier (26), wherein the power module (10) has a printed circuit board (29) which is equipped with components of a control device (30a-b) for generating control signals, wherein the power module (10) has a plurality of signal pins (20, 20a-b, 22, 22a-b) for transmitting the control signals to the power switches, wherein the signal pins (20, 20a-b, 22, 22a-b) are electrically connected on the one hand to the circuit carrier (26) and on the other hand to the printed circuit board (29), wherein the signal pins (20, 20a-b, 22, 22a-b) have one or more signal pin pairs (24,24a-b) each consisting of at least two signal pins (20,20a-b,22,22a-b) twisted together, characterized bythat the signal pin pairs (24,24a-b) are each at least partially covered with an electromagnetic shield. [2] Power module (10) according to claim 1, wherein a first signal pin (20, 20a-b) of the respective signal pin pair (24, 24a-b) is electrically connected to a control electrode of a corresponding power switch. [3] Power module (10) according to claim 2, wherein a second signal pin (22, 22a-b) of the respective signal pin pair (24, 24a-b) is electrically connected to a negative-pole current electrode of the corresponding power switch. [4] Power module (10) according to one of claims 1 to 3, wherein at least one signal pin pair (24) for transmitting control signals to an auxiliary switch is electrically connected to a control electrode and a negative-pole current electrode of the auxiliary switch. [5] The power module (10) of claim 4, wherein the auxiliary switch comprises an active Miller Clamping (AMC) auxiliary switch, a short circuit protection auxiliary switch, a temperature sensor auxiliary switch, or a current sensor auxiliary switch. [6] Power module (10) according to one of claims 1 to 5, wherein the signal pin pairs (24.24ab) are each at least partially covered with an electrically insulating coating (23). [7] Converter for use in an at least partially electrified vehicle, comprising one or more power modules (10) according to one of the preceding claims. [8] Electric axle drive for an at least partially electrified vehicle, comprising an electric motor, a transmission device and a converter according to claim 7. [9] Vehicle, in particular at least partially electrified vehicle, comprising an electric axle drive according to claim 8.

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