DE102022213003A1 - Power module for a converter with twisted signal pin pairs for control signal routing - Google Patents

Abstract

The present invention relates to a 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 can be switched to convert an input current into an output current and are mounted on a circuit carrier (26), wherein the power module (10) has a circuit board (29) which is equipped with components of a control device (30a-b) for generating control signals, wherein the power module (10) has several signal pins (20,20a-b,22,22a-b) for transmitting the control signals to the power switches which are electrically connected on the one hand to the circuit carrier (26) and on the other hand to the 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 two signal pins twisted together (20,20a-b,22,22a-b).

Description

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. The invention also relates to an electric axle drive with such a power module and a vehicle with such an electric axle drive.

Pure electric vehicles and hybrid vehicles are known in the state of the art, which are powered exclusively or with the support of one or more electric machines as drive units. Such electrified vehicles generally use a rechargeable vehicle drive battery that provides a direct current (DC voltage) by means of which the electric machines are powered. To do this, the DC voltage is converted into an alternating current (AC voltage) by means of a DC/AC inverter in order to power the electric machines with a multi-phase alternating current (AC current).

The core component of such converters is a power electronics system, which has a large number of power switches. These power switches are interconnected to form a half-bridge arrangement comprising one or more half-bridges. Each half-bridge is made up of a high-side device and a low-side device, each of which has one or more power switches connected in parallel. 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).

The power switches are switched in a targeted manner for the purpose of voltage conversion. 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 terms of signal technology. In the power modules known from the prior art, signal pins are used for this purpose, which are each electrically connected on the one hand to a control electrode and on the other hand to a circuit board that is equipped with the components of the control device.

However, the known power modules have the disadvantage that the arrangement of the signal pins there is, due to their design, subject to a 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 can 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 represents a high risk of impairment for the entire converter.

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.

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 emerge from the dependent patent claims.

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 (converter) in order to recharge the vehicle drive battery, for example. 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.

The power module comprises at least one power switch, preferably a plurality of power switches, for feeding in 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 of which has a half-bridge. Each phase or half-bridge is used to convert the fed-in DC current into a phase current by switching the associated power switches, wherein the plurality of these generated phase currents are phase-shifted from one another and are each fed into a winding of the electric machine 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 fed-in AC current, resulting in a DC current at the output.

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 high side and a module low side, 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 high side of the phase is formed by the module high side and the low side of the phase is formed by the module low side of the single half-bridge module. In the latter case, the high side of the phase is formed by a parallel connection of the module high sides of the half-bridge modules connected in parallel, with the low side of the phase being formed by a parallel connection of the module low sides of the half-bridge modules connected in parallel. Alternatively, the power module can comprise only one module high side or one module low side. The case in which the power module has a single power switch occurs when the module high side or the module low side comprises only a single power switch. Alternatively, the power module can refer to the totality of the parallel-connected half-bridge modules of a phase, or to the totality of the parallel-connected module high sides or module low sides of a phase.

The power switches are preferably transistors, such as MOSFETs, HEMTs and/or IGBTs. The semiconductor material on which the power switches are based 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 on a circuit carrier, e.g. a circuit board/circuit board such as 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.

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 take the output current from the power module, several power connections 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 to be carried 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 is carried within the power module, for example between the individual circuit breakers, using several power lines, which are designed as wire bonds or integrated in a conductor frame.

In addition, the power module comprises a circuit board which is 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 circuit board, in particular a driver board. The circuit board preferably extends in a plane that is essentially parallel to the circuit carrier.

According to the invention, the power module has several 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 circuit board on the other hand, 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 connected to one another. which are twisted or wound 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 (eg 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 (eg source electrode) of the corresponding power switch.

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, 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 this. 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, with a second signal pin of the signal pin pair being electrically connected to a negative-pole current electrode (e.g. source electrode) of the auxiliary switch.

By twisting the signal pin pairs or twisted pair cables (TPC), the influences from external electromagnetic fields can largely cancel each other out. In this way, crosstalk between the signal lines routed in pairs is advantageously minimized, so that common-mode rejection is achieved. The gate loop inductance can be reduced as a result. Twisted signal pin pairs therefore provide better protection against electrical and magnetic interference, especially compared to signal lines routed in parallel.

In addition, the twisted arrangement of the signal pins in pairs allows for a form flexibility of the signal pin pairs, which are preferably in the form of cables, which enables tolerance compensation with an increased degree of freedom of movement when attaching the signal pins to the power module. Alternatively, the signal pin pairs can be made of 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 solder connection (e.g. thermode soldering), a weld connection (e.g. ultrasonic welding) or a metallic connection. However, the method of connection is not limited to the examples mentioned above.

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, several signal pin pairs can be covered by the same insulating coating.

According to a further embodiment, the signal pin pairs are each covered at least in sections with an electromagnetic shield. This measure advantageously provides an additional shield 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 (such as a copper layer) within the electrically insulating coating. A metallic inner layer refers, for example, to a metallic sheathing of the signal pin pair.

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 restricted 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.

The invention is explained below by way of example using embodiments shown in the figures.

• 1 eine schematische Darstellung des Leistungsmoduls mit Signalpinpaaren bestehend jeweils aus zwei verdrillten Signalpins gemäß einer Ausführungsform in einer Seitenansicht;
• 2 eine schematische Darstellung des Leistungsmoduls gemäß einer weiteren Ausführungsorm in einer Perspektivansicht, wobei die Signalpinpaare jeweils mit einer elektrisch isolierenden Beschichtung umhüllt sind;
• 3 eine weitere schematische Darstellung des Leistungsmoduls gemäß der weiteren Ausführungsorm aus 2 in einer Perspektivansicht.

Show it:

• 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;
• 2 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;
• 3 a further schematic representation of the power module according to the further management form 2 in a perspective view.

Identical objects, functional units and comparable components are designated with the same reference symbols across all figures. These objects, functional units and comparable components are identical in terms of their technical features, unless the description explicitly or implicitly indicates otherwise.

1 shows a schematic representation of a power module 10 according to an 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 (converter) or as a DC/DC converter.

The power module 10 comprises at least one power switch, preferably several 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 several (for example three) phases, each of which has a half-bridge. Each phase or half-bridge is used to convert the fed-in DC current into a phase current by switching the associated power switches, wherein the several phase currents generated on these are phase-shifted from one another and are each fed into a winding of the electric machine in order 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.

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 high side and a module low side, 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 high side of the phase is formed by the module high side and the low side of the phase is formed by the module low side of the single half-bridge module. In the latter case, the high side of the phase is formed by a parallel connection of the module high sides of the half-bridge modules connected in parallel, wherein the low side of the phase is formed by a parallel connection of the module low sides of the half-bridge modules connected in parallel. Alternatively, the power module 10 can comprise only one module high side or one module low side. The case in which the power module 10 has a single power switch occurs when the module high side or the module low side 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 high sides or module low sides of a phase.

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 2-3 ), eg a printed circuit board (PCB), or a multilayered ceramic substrate, at least partially coated with a metal (eg 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 insulating layer is preferably arranged between the first metal layer and the second metal layer. The cooler 25 can, as in 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.

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 circuit breaker through which the load current flows when the circuit breaker is open (conductive). The ground potential is preferably provided by a metallic layer of the circuit carrier 29 on which the circuit breakers are arranged. To feed the input current (load current) into the power module 10 or to take the output current from the power module 10, several power connections 14, 16, 18 are provided in the power module 10, which are electrically connected to the current electrodes of the respective circuit breaker. The power connections 14, 16, 18 are connected to busbars 13, 15, 17 in order to enable current to be carried 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 machine to be powered. The current is carried within the power module 10, for example between the individual circuit breakers, by means of several power lines, which are designed, for example, as wire bonds or integrated in a conductor frame.

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

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 that is essentially parallel to the circuit carrier 26. As in 1 As shown by way of example, a first control device 30a is assigned to the high side of a half-bridge, with a second control device 30b being assigned to the low side of the half-bridge. The first control device 30a is therefore designed to control the high-side power switches, with the second control device 30b being designed to control the low-side power switches.

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 circuit board on the other. As shown in 1 As shown schematically and by way of example, the signal pins form one or more signal pin pairs 24a-b, each consisting of two signal pins 20a, 22a; 20b, 22b twisted together. In a first signal pin pair 24a, which is assigned to the high side, two signal pins 20a, 22a run, each representing a signal line, the signal lines being 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, 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. Similarly, in a second signal pin pair 24b, which is assigned to the low side, two signal pins 20b, 22b run, each representing a signal line, whereby 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, whereby 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, so that potential separation between the twisted signal pins 20a-b, 22a-b is ensured.

By twisting the signal pin pairs 24a-b, influences from external electromagnetic fields can largely cancel each other out. In this way, crosstalk between the signal lines routed in pairs is advantageously minimized, so that common-mode suppression is achieved. Therefore, twisted signal pin pairs 24a-b enable better protection against electrical and magnetic interference, especially compared to signal lines routed in parallel.

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, ie semiconductor switches that are not part of a high side or low side in a half bridge. Examples of auxiliary switches are 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 this. Analogous to 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 electrically connected to a negative-pole current electrode (e.g. source electrode) of the auxiliary switch.

As in 2 As shown schematically and by way of example, the signal pin pairs 24 are each at least partially covered 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, several signal pin pairs 24 can be covered by an identical insulating coating 23.

In addition to the electrical insulation, the signal pin pairs 24 can each be covered at least in sections with an electromagnetic shield. This measure advantageously provides an additional shield 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. copper layer) within the electrically insulating coating 23.

Reference symbols

10

Power module

11

current-insulating protective covering (protective overmolding)

13

positive pole DC power rail

14

positive-pole DC power connection

15

negative pole DC power rail

16

negative 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

cooler

252

Top

26

Circuit board (PCB)

262

Top

27

thermally conductive layer (sintered layer)

29

Circuit board (driver board)

30a-b

Control device

Claims (10)

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 can be switched to convert an input current into an output current and are mounted on a circuit carrier (26), wherein the power module (10) has a circuit board (29) which is equipped with components of a control device (30a-b) for generating control signals, wherein the power module (10) has several 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 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 interconnected twisted signal pins (20,20a-b,22,22a-b). 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. 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. Power module (10) according to one of the Claims 1 until 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. Power module (10) according to Claim 4 , wherein the auxiliary switch comprises an Active Miller Clamping, ACM, auxiliary switch, a short circuit protection auxiliary switch, a temperature sensor auxiliary switch, or a current sensor auxiliary switch. Power module (10) according to one of the Claims 1 until 5 , wherein the signal pin pairs (24.24ab) are each covered at least in sections with an electrically insulating coating (23). Power module (10) according to one of the Claims 1 until 6 , wherein the signal pin pairs (24,24a-b) are each at least partially covered with an electromagnetic shield. Converter for use in an at least partially electrified vehicle, comprising one or more power modules (10) according to one of the preceding claims. Electric axle drive for an at least partially electrified vehicle, comprising an electric machine, a transmission device and a converter according to Claim 8 . Vehicle, in particular at least partially electrified vehicle, comprising an electric axle drive according to Claim 9 .

Images