DE102022210965A1 - Power converter for an electric axle drive of a motor vehicle, electric axle drive for a motor vehicle, motor vehicle and method for producing a power converter - Google Patents

Abstract

A power converter (130) for an electric axle drive of a motor vehicle comprises direct current connections for an electric direct current from an electrical energy storage device of the motor vehicle and alternating current connections for providing an electric alternating current for an electrical machine of the electric axle drive. The power converter (130) also comprises a plurality of switching devices (235) for converting the direct current into the alternating current. The switching devices (235) are arranged in at least one housing (360), wherein the at least one housing (360) has connection pins (335) for through-hole mounting. The power converter (130) further comprises a circuit board (334) on which the direct current connections, the alternating current connections and the at least one housing (360) of the switching devices (235; S1, S2, S3, S4, S5, S6) are arranged. The circuit board (334) is shaped for through-hole mounting of the connection pins (335).

Description

The present invention relates to a power converter for an electric axle drive of a motor vehicle, to an electric axle drive for a motor vehicle, to a motor vehicle and to a method for producing such a power converter.

In the field of power converters for electric axle drives for motor vehicles or, in other words, in the field of automobile or automotive traction inverters, integrated B6 bridge modules, integrated half-bridge modules or discrete individual switches are conventionally used.

Against this background, the present invention provides an improved power converter for an electric axle drive of a motor vehicle, an improved electric axle drive for a motor vehicle, an improved motor vehicle and an improved method for producing a power converter according to the main claims. Advantageous embodiments emerge from the subclaims and the following description.

The advantages that can be achieved with the approach presented are in particular that a thermally optimized discrete package can be provided for fast-switching semiconductors of a power converter for an electric axle drive of a motor vehicle, whereby a reduction in thermomechanical stress can be achieved for a fast-switching package. In particular, for semiconductor modules such as switching devices of power converters, a good thermal connection can be achieved with reduced mechanical stress. Good thermal connection means that the package or the switching device can be mechanically fixed perfectly, e.g. by soldering, sintering or gluing. For example, switching devices of such a power converter can be attached to a circuit board of the power converter using through-hole mounting or plug-in mounting via mechanically flexible THT pins (THT = Through-Hole Technology) or connection pins for through-hole mounting instead of using surface mounting technology (SMT for short). This means that switching devices of such a power converter can have THT pins instead of SMT pins, whereby a mechanically rigid connection with the potential for pins to break off can be prevented. Due to the assembly using THT pins or pins for through-hole assembly, the mechanical stress that can arise from thermo-mechanical stress can be compensated.

• Gleichstromanschlüsse für einen elektrischen Gleichstrom von einem elektrischen Energiespeicher des Kraftfahrzeugs;
• Wechselstromanschlüsse zum Bereitstellen eines elektrischen Wechselstroms für eine elektrische Maschine des elektrischen Achsantriebs;
• eine Mehrzahl von Schalteinrichtungen zum Wandeln des Gleichstroms in den Wechselstrom, wobei die Schalteinrichtungen in mindestens einem Gehäuse angeordnet sind, wobei das mindestens eine Gehäuse Anschlussstifte für Durchsteckmontage aufweist; und
• eine Leiterplatte, an der die Gleichstromanschlüsse, die Wechselstromanschlüsse und das mindestens eine Gehäuse der Schalteinrichtungen angeordnet sind, wobei die Leiterplatte zur Durchsteckmontage der Anschlussstifte ausgeformt ist.

A power converter for an electric axle drive of a motor vehicle is presented, whereby the power converter has the following features:

• DC connections for a direct electrical current from an electrical energy storage device of the motor vehicle;
• AC connections for providing an alternating electrical current for an electric machine of the electric axle drive;
• a plurality of switching devices for converting the direct current into the alternating current, the switching devices being arranged in at least one housing, the at least one housing having connection pins for through-hole mounting; and
• a printed circuit board on which the direct current connections, the alternating current connections and the at least one housing of the switching devices are arranged, wherein the printed circuit board is shaped for through-hole mounting of the connection pins.

Furthermore, on the side of the switching devices facing away from the circuit board, a contact surface for electrical and thermal connection is arranged. This contact surface is usually called a "pad". This allows thermomechanical relief of the switching devices to be achieved via the connection pins.

Advantageously, the contact surface can be designed as a metal plate, in particular as a copper plate or block.

In this case, one of the connection pins can advantageously be assigned to a first potential, in particular the positive potential of a battery, the second connection pin to a second potential, in particular the negative potential of a battery, and the contact surface can also be assigned to one of the two potentials, in particular the second potential.

The motor vehicle can be, for example, a land vehicle, in particular a passenger car, a motorcycle, a commercial vehicle or the like. The power converter can be designed and referred to as an inverter. The power converter can be designed to convert the direct current from the electrical energy storage device of the motor vehicle into the alternating current for the electrical machine of the electric axle drive of the motor vehicle. The power converter can also have an intermediate circuit capacitor. Each of the switching devices can have a transistor, in particular a power transistor, or be designed as such a transistor. A unit comprising at least one Switching device, a housing and connection pins can be referred to as a semiconductor module. The power converter can have at least one such semiconductor module. Contact holes can be formed in the circuit board. Each of the contact holes can be formed to receive one of the connection pins of the switching devices.

According to one embodiment, each of the switching devices can be arranged in its own housing. Thus, a number of semiconductor modules each comprising a switching device, a housing and connection pins can be provided, wherein the number of semiconductor modules can correspond to the plurality of switching devices. Such an embodiment offers the advantage that the switching devices can be designed as discrete packages or semiconductor modules. Such discrete structures can offer good scalability and, due to the low complexity, an advantageous competitive situation on the market and low costs.

Additionally or alternatively, at least two switching devices can be arranged in a common housing. Thus, at least two switching devices can be combined in a semiconductor module, which can have a common housing and connection pins. The power converter can have at least one such semiconductor module. Such an embodiment offers the advantage that the switching devices can be designed as integrated semiconductor modules or power modules. This can reduce the complexity of integrating such switching devices into the power converter or traction inverter.

According to one embodiment, the power converter can have six switching devices that can be connected in a B6 bridge circuit. Such an embodiment offers the advantage of enabling a reliable, efficient and cost-effective conversion of the direct current into the alternating current.

The power converter can also have a cooling device that can be thermally coupled at least to the switching devices. A cooling device can be understood to mean, for example, an active or passive cooler, as is typically used in connection with electrical circuits. Optionally, a coolant can flow through the cooling device in order to increase cooling performance. Using the cooling device, thermal energy generated by the operation of the power converter can be dissipated from the switching devices. Such an embodiment offers the advantage that reliable heat dissipation can be achieved from at least the switching devices. This can also enable, for example, fast switching operations of the switching devices.

Furthermore, the power converter can have at least one interference suppression capacitor, which can be arranged on the circuit board. The at least one interference suppression capacitor can be electrically connected to at least one of the direct current connections and to ground. The at least one interference suppression capacitor can be designed as a class Y capacitor. Such an embodiment offers the advantage that high-frequency interference signals can be eliminated and thus a reduction in electromagnetic interference can be achieved.

In particular, the direct current connections can be arranged in a direct current region of the power converter. In this case, the alternating current connections can be arranged in an alternating current region of the power converter. In this case, the alternating current region can be arranged between two parts of the direct current region with respect to a dimension axis of the power converter. The dimension axis can represent a width dimension, a length dimension or a diagonal dimension of the power converter. A first part of the direct current region can have a first direct current connection and a second part of the direct current region can have a second direct current connection. Such an embodiment offers the advantage of enabling a compact construction of the power converter.

In addition, the invention relates to an electric axle drive for a motor vehicle with at least one electric machine, a transmission device and an embodiment of a power converter described herein.

The power converter can be designed as a power inverter. Using the power converter, an alternating electrical current required to operate the electrical machine can be provided. Using the transmission device, a torque provided by the electrical machine can be converted into a drive torque for driving at least one wheel of the motor vehicle. The transmission device can have a transmission for reducing the speed of the electrical machine and optionally a differential.

In addition, the invention relates to a motor vehicle with an embodiment of a power converter mentioned herein and additionally or alternatively with an embodiment of an electric axle drive mentioned herein.

Accordingly, a motor vehicle may comprise a power converter as mentioned herein and additionally or alternatively a mentioned electric axle drive.

• Bereitstellen der Gleichstromanschlüsse, der Wechselstromanschlüsse, der Mehrzahl von Schalteinrichtungen, die in dem mindestens einem Gehäuse (360) angeordnet sind, das die Anschlussstifte für die Durchsteckmontage aufweist, und der Leiterplatte, die zur Durchsteckmontage der Anschlussstifte ausgeformt ist; und
• Anordnen der Gleichstromanschlüsse, der Wechselstromanschlüsse und des mindestens einen Gehäuses an der Leiterplatte, wobei das Gehäuse mittels Durchsteckmontage der Anschlussstifte an der Leiterplatte befestigt wird.

A method for producing an embodiment of a power converter mentioned herein is also presented, the method comprising the following step:

• Providing the DC terminals, the AC terminals, the plurality of switching devices arranged in the at least one housing (360) having the terminal pins for through-hole mounting, and the circuit board shaped for through-hole mounting of the terminal pins; and
• Arranging the DC terminals, the AC terminals and the at least one housing on the circuit board, wherein the housing is attached to the circuit board by through-hole mounting of the terminal pins.

By carrying out such a method, a power converter as mentioned herein can be produced with advantageous properties and additionally or alternatively in an advantageous manner.

• 1 eine schematische Darstellung eines Ausführungsbeispiels eines Kraftfahrzeugs;
• 2 eine schematische Darstellung eines Ausführungsbeispiels eines Stromrichters für einen elektrischen Achsantrieb eines Kraftfahrzeugs;
• 3 eine schematische Darstellung eines Ausführungsbeispiels eines Stromrichters für einen elektrischen Achsantrieb eines Kraftfahrzeugs;
• 4 eine schematische Darstellung eines Gehäuses einer Schalteinrichtung aus 3;
• 5 eine schematische Darstellung des Gehäuses aus 4; und
• 6 ein Ablaufdiagramm eines Ausführungsbeispiels eines Verfahrens zum Herstellen eines Stromrichters.

The invention is explained in more detail by way of example with reference to the accompanying drawings. They show:

• 1 a schematic representation of an embodiment of a motor vehicle;
• 2 a schematic representation of an embodiment of a power converter for an electric axle drive of a motor vehicle;
• 3 a schematic representation of an embodiment of a power converter for an electric axle drive of a motor vehicle;
• 4 a schematic representation of a housing of a switching device from 3 ;
• 5 a schematic representation of the housing 4 ; and
• 6 a flow chart of an embodiment of a method for producing a power converter.

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.

1 shows a schematic representation of an embodiment of a motor vehicle 100. The motor vehicle 100 is shown in the illustration of 1 Here, wheels 105, just four wheels 105 as an example, an electrical energy storage device 110, for example a battery, and an electric axle drive 120 are shown. The electric axle drive 120 comprises a power converter 130, an electric machine 140 and a transmission device 150.

Electrical energy for operating the electric machine 105 is provided by an energy supply device, here the electrical energy storage device 110. The electrical energy storage device 110 is designed to provide direct current, which is converted into an alternating current, for example a three-phase alternating current, using a power converter 130 of the electric axle drive 120 and is provided to the electric machine 140. A shaft driven by the electric machine 140 is coupled to at least one wheel 105 of the motor vehicle 100 directly or using the transmission device 150. The motor vehicle 100 can thus be moved using the electric machine 140. According to one embodiment, the electric axle drive 120 comprises a housing in which the power converter 130, the electric machine 140 and the transmission device 150 are arranged.

In particular, the power converter 130 will be discussed in more detail with reference to the following figures.

2 shows a schematic representation of an embodiment of a power converter 130 for an electric axle drive of a motor vehicle. The power converter 130 corresponds or is similar to the power converter from 1 . Furthermore, in addition to the power converter 130, for illustration purposes in 2 also the electrical energy storage unit 110 and the electric machine 140 of the electric axle drive are shown.

The power converter 130 comprises direct current connections 231, a plurality of switching devices 235, alternating current connections 237 and a circuit board, which is omitted from the figure for reasons of illustration. According to the embodiment shown here, the power converter 130 further comprises an intermediate circuit capacitor 233. The direct current connections 231 are arranged in a direct current area 232. The alternating current connections 237 are arranged in an alternating current area 238.

The DC terminals 231 are for a direct electrical current from the electrical Energy storage device 110 of the motor vehicle is provided. In other words, the power converter 130 can be connected or is connected to the electrical energy storage device 110 via the direct current connections 231. The alternating current connections 237 are provided for providing an alternating electrical current for the electrical machine 140 of the electric axle drive. In other words, the power converter 130 can be connected or is connected to the electrical machine 140 via the alternating current connections 237. The direct current connections 231 and/or the alternating current connections 237 are each shaped, for example, to accommodate one end of a power cable and to make mechanical and electrical contact, for example by screwing, clamping or soldering.

The switching devices 235 are designed to convert the direct current into alternating current. Even if it is 2 is not explicitly shown, the switching devices 235 are either arranged in a housing or distributed over several housings. For example, each of the switching devices can have its own housing or two or more of the switching devices can be arranged together in a common housing. A housing including integrated switching device or switching devices can represent a discrete, separately handled component. The housing or housings are equipped with connection pins for through-hole mounting on the circuit board. The connection pins are used for electrical contacting of the switching devices 235 and for mechanically fastening the housing or housings and thus the switching devices 235 to the circuit board.

The direct current connections 231, the alternating current connections 237 and the at least one housing of the switching devices 235 are arranged on the circuit board. The circuit board is shaped for through-hole mounting of the connection pins of the switching devices 235 or of the at least one housing of the switching devices 235.

According to one embodiment, each of the switching devices 235 is arranged in its own housing. Alternatively, at least two of the switching devices 235 are arranged in a common housing.

According to the exemplary embodiment shown here, the power converter 130 comprises, by way of example, only six switching devices 235, here a first switching device S1, a second switching device S2, a third switching device S3, a fourth switching device S4, a fifth switching device S5 and a sixth switching device S6. The switching devices 235 or S1, S2, S3, S4, S5 and S6 are connected in a B6 bridge circuit. A first of the direct current connections 231 is electrically connected to a first connection of the first switching device S1, a first connection of the third switching device S3 and a first connection of the fifth switching device S5. A second of the direct current connections 231 is electrically connected to a first connection of the second switching device S2, a first connection of the fourth switching device S4 and a first connection of the sixth switching device S6. A first of the alternating current connections 237 is electrically connected to a second connection of the first switching device S1 and a second connection of the second switching device S2. A second of the AC terminals 237 is electrically connected to a second terminal of the third switching device S3 and a second terminal of the fourth switching device S4. A third of the AC terminals 237 is electrically connected to a second terminal of the fifth switching device S5 and a second terminal of the sixth switching device S6. The intermediate circuit capacitor 233 is electrically connected to the first of the DC terminals 231 and the second of the DC terminals 231.

According to one embodiment, the power converter 130 can be operated in the opposite direction so that the electric machine 140 can be used as a generator for charging the electrical energy storage device 110.

3 shows a schematic representation of an embodiment of a power converter 130 for an electric axle drive of a motor vehicle. The power converter 130 corresponds or is similar to the power converter from 1 and or 2 . The power converter 130 is in 3 shown in a schematic sectional view, in particular a cross-sectional view.

The power converter 130 comprises the direct current connections, the plurality of switching devices 235, the alternating current connections and the circuit board 334. According to the embodiment shown here, the power converter 130 further comprises an optional cooling device 336 and, merely by way of example, two interference suppression capacitors 339 and two ground areas GND.

The DC connections are arranged in the DC area 232, two parts of which are shown here. The AC connections are arranged in the AC area 238, which is arranged between the two parts of the DC area 232 with respect to a dimension axis (A) of the power converter 130. The dimension axis (A) extends in the illustration of 3 in the cutting plane parallel to the circuit board 334. In other words, the dimension axis (A) extends along a width dimension of the power converter 130.

The direct current connections are provided for an electrical direct current from the electrical energy storage device of the motor vehicle. In other words, the power converter 130 can be connected or is connected to the electrical energy storage device via the direct current connections. The alternating current connections are provided for providing an electrical alternating current for the electrical machine of the electric axle drive. In other words, the power converter 130 can be connected or is connected to the electrical machine via the alternating current connections.

The switching devices 235 are designed to convert the direct current into alternating current. The switching devices 235 are arranged in at least one housing 360, which has connection pins 335 for through-hole mounting on the circuit board 334. The connection pins 335 serve to electrically contact the switching devices 235.

The direct current connections or the direct current area 232, the alternating current connections or the alternating current area 238 and the at least one housing 360 of the switching devices 235 are arranged on the circuit board 334. The circuit board 334 is shaped for the through-hole mounting of the connection pins 335 of the switching devices 235 or the at least one housing 360 of the switching devices 235. For this purpose, the circuit board 334 has contact holes for receiving the connection pins 335.

In the presentation of 3 By way of example, only two switching devices 235 with their connection pins 335 and housings 360 are shown. Each of the switching devices 235 is arranged in its own housing 360 and mounted on the circuit board 334 via connection pins 335 by means of through-hole mounting. Thus, for example, each of the switching devices 235 is provided as a discrete package.

For example, in one of the housings 360 only the 2 shown switching device S1 and in the other of the housings 360 only the 2 According to an alternative embodiment, the switching device S2 shown in FIG. 3 is integrated in one of the housings 360. 2 shown switching devices S1, S3 and S5 and in the other of the housings 360 the in 2 shown switching device S2, S4, S6 are integrated. Accordingly, other combinations and also the use of more than the two housings 360 shown or the use of only one of the housings 360 in which all switching devices are then arranged are possible.

The cooling device 336 is thermally coupled at least to the switching devices 235. The cooling device 336 is designed to dissipate heat from the switching devices 235. For example, the cooling device 336 is thermally coupled to a ceiling section of the at least one housing 360. The interference suppression capacitors 339 are arranged on the circuit board 334. The interference suppression capacitors 339 are electrically connected to the direct current connections or the parts of the direct current area 232 and to ground or the ground area GND.

The contact surfaces 361 preferably extend over the entire side facing away from the circuit board 334. Alternatively, they can also occupy only a portion of the surface.

4 shows a schematic representation of a housing 360 for at least one switching device 235, as shown by way of example in 3 is shown. A plurality of connection pins 335 for through-hole mounting or plug-in mounting are shown here from the housing 360. The at least one switching device 235 is arranged integrated in the housing 360. In the illustration of 4 the housing 360 is shown in an oblique view. The connection pins 335 are arranged in two rows, for example. The connection pins 335 are led out of opposite side walls of a body of the housing 360 and each have a right-angled bend, so that free ends of the connection pins 335, which are intended to be led through contact holes in the circuit board, are aligned parallel to the side walls of the housing 360. The free ends of the connection pins 335 extend out over a base of the body of the housing 360.

According to one embodiment, the bottom of the body of the housing 360 has no contact surface for establishing a soldered connection to the circuit board. Electrical contacting of the at least one switching device 235 integrated into the housing 360 takes place exclusively via the connection pins 335.

5 shows a schematic representation of the housing 360 from 4 . The housing 360 is shown in the illustration of 5 shown in a side view. The connection pins 335 for through-hole mounting or plug-in mounting are also shown here.

6 shows a flow chart of an embodiment of a method 600 for producing len of a power converter. By carrying out the method 600 for manufacturing, a power converter can be manufactured which corresponds to or is similar to the power converter from one of the figures described here. In other words, by carrying out the method 600 for manufacturing, a power converter can be manufactured which has the features of the power converter from one of the figures described here or a similar power converter. The method 600 for manufacturing comprises a step 601 in which the required parts, in particular the direct current connections, the alternating current connections, the plurality of switching devices which are arranged in the at least one housing and the circuit board, are provided. In a step 602 of arranging, the direct current connections, the alternating current connections and the at least one housing of the switching devices are arranged on the circuit board. The at least one housing is attached to the circuit board by means of through-hole mounting of the connection pins. For this purpose, the housing is placed on the circuit board in such a way that the connection pins are guided through corresponding through holes in the circuit board. For electrical and mechanical contact, the connection pins are soldered, for example. The step 602 of arranging can comprise several sub-steps, wherein in each sub-step one of the elements is arranged on the circuit board.

Reference symbols

100

Motor vehicle

105

Wheels

110

electrical energy storage

120

electric axle drive

130

Power converter

140

electric machine

150

Gearbox device

231

DC connections

232

DC range

233

DC link capacitor

235

Switching devices

237

AC connections

238

AC range

S1

first switching device

S2

second switching device

S3

third switching device

S4

fourth switching device

S5

fifth switching device

S6

sixth switching device

334

Circuit board

335

Connector pins

336

Cooling device

339

Suppression capacitor

360

Housing

361

Contact surface

A

Dimension axis

GND

Mass range

600

Method of manufacturing

601

Deployment step

602

Step of arranging

Claims (11)

Power converter (130) for an electric axle drive (120) of a motor vehicle (100), the power converter (130) having the following features: DC connections (231) for an electric direct current from an electric energy storage device (110) of the motor vehicle (100); AC connections (237) for providing an electric alternating current for an electric machine (140) of the electric axle drive (120); a plurality of switching devices (235; S1, S2, S3, S4, S5, S6) for converting the direct current into the alternating current, the switching devices (235; S1, S2, S3, S4, S5, S6) being arranged in at least one housing (360), the at least one housing (360) having connection pins (335) for through-hole mounting; and a circuit board (334) on which the direct current connections (231), the alternating current connections (237) and the at least one housing (360) of the switching devices (235; S1, S2, S3, S4, S5, S6) are arranged, wherein the circuit board (334) is shaped for through-hole mounting of the connection pins (335), wherein on the side of the switching devices (235; S1, S2, S3, S4, S5, S6) facing away from the circuit board, a contact surface (361) for electrical and thermal connection is arranged. Power converter (130) according to Claim 1 , wherein each of the switching devices (235) is arranged in a separate housing (360). Power converter (130) according to Claim 1 , wherein at least two switching devices (235) are arranged in a common housing (360). Power converter (130) according to one of the preceding claims, wherein the power converter (130) six switching devices (235; S1, S2, S3, S4, S5, S6) which are connected in a B6 bridge circuit. Power converter (130) according to one of the preceding claims, with a cooling device (336) which is thermally coupled at least to the switching devices (235). Power converter (130) according to one of the preceding claims, with at least one interference suppression capacitor (339) which is arranged on the circuit board (334), wherein the at least one interference suppression capacitor (339) is electrically connected to at least one of the direct current terminals (231, 232) and to ground (GND). Power converter (130) according to one of the preceding claims, wherein the direct current connections (231) are arranged in a direct current region (232) of the power converter (130), wherein the alternating current connections (237) are arranged in an alternating current region (238) of the power converter (130), wherein, with respect to a dimensional axis (A) of the power converter (130), the alternating current region (238) is arranged between two parts of the direct current region (232). Power converter (130) according to one of the preceding claims, wherein Electric axle drive (120) for a motor vehicle (100), wherein the electric axle drive (120) comprises at least one electric machine, a transmission device and a power converter (130) according to one of the preceding claims. Motor vehicle (100) comprising a power converter (130) according to one of the Claims 1 until 7 and/or an electric axle drive (120) according to Claim 8 . Method (600) for producing a power converter (130) according to one of the Claims 1 until 7 , wherein the method (600) comprises the step of: providing (601) the direct current terminals (231), the alternating current terminals (237), the plurality of switching devices (235; S1, S2, S3, S4, S5, S6) arranged in the at least one housing (360) having the connection pins (335) for through-hole mounting, and the circuit board (334) shaped for through-hole mounting of the connection pins (335); and arranging (602) the direct current terminals (231), the alternating current terminals (237) and the housing (360) of the switching devices (235) on the circuit board (334), wherein the housing (360) is attached to the circuit board (334) by means of through-hole mounting of the connection pins (335).

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