DE102017216250A1 - Drive a motor vehicle - Google Patents

Abstract

The invention relates to a drive (16) of a motor vehicle (2), comprising a brushless electric motor (20), and an inverter (18) having a link capacitor (28) comprising two electrodes (33) and an inverter (40). The inverter (40) is electrically arranged between the electric motor (20) and the DC link capacitor (28), and the electrodes (33) of the DC link capacitor (28) are each guided by a feedthrough capacitor (44) to ground (6). The invention further relates to a motor vehicle (2) with a drive (16).

Description

The invention relates to a drive of a motor vehicle, with a brushless electric motor, and with a converter. The invention further relates to a motor vehicle with a drive.

Motor vehicles have a (main) drive, by means of which the propulsion is created. The main drive has, for example, an internal combustion engine, in which by means of combustion of a fuel, a rotational movement is generated. As an alternative, electric motors are known in which by means of energization of an electromagnet, a rotor of the electric motor is placed in a rotational movement, which is coupled to a drive wheel of the motor vehicle. The electromagnet is usually a component of a stator of the electric motor having a number of such electromagnets. The rotor itself comprises a number of permanent magnets.

Usually, the electric motor is designed brushless, which reduces wear. To energize the electromagnet of the electric motor, therefore, an electric current is required, which is tuned to the desired speed and the desired torque of the electric motor. For this purpose, usually a converter is used, which is usually designed in three phases. The inverter has a bridge circuit with three bridge branches, each comprising two series-connected semiconductor switches. With each of the bridge branches, a phase of the electric motor is electrically contacted, wherein each of the phases is associated with at least one of the electromagnets of the electric motor.

By actuating the semiconductor switches of the inverter, it is possible to set a current flow from the inverter to the electric motor.

Due to the actuation of the semiconductor switches, an electric current is switched so that within a comparatively short time the electric current flow is changed. As a result, electromagnetic interference is generated, which couple into an electrical system of the motor vehicle, by means of which a current supply of the inverter takes place. Also, such disturbances are transmitted to the electric motor. These disturbances radiate, for example via any lines to other components of the motor vehicle, as to ancillaries, so their functioning is impaired.

Consequently, it is necessary to reduce such disturbances. For this purpose, usually filters are used, which are coupled to the inverter. These usually have a high and / or low pass, so that comparatively high-frequency or low-frequency interference are filtered out, which increases the EMC compatibility of the drive. However, such filters are relatively expensive, which is why the production costs are increased by such a drive.

The invention has for its object to provide a particularly suitable drive a motor vehicle and a particularly suitable motor vehicle with a drive, wherein advantageously manufacturing costs are reduced.

With regard to the drive this object is achieved by the features of claim 1 and in terms of the motor vehicle by the features of claim 9 according to the invention. Advantageous developments and refinements are the subject of the respective subclaims.

The drive is part of a motor vehicle and has a brushless electric motor and a converter. The drive is, for example, a drive of an accessory of the motor vehicle, such as a pump or a fan. In other words, the drive does not serve the propulsion of the motor vehicle. However, particularly preferably, the drive is a main drive of the motor vehicle and consequently serves the propulsion of the motor vehicle. Here, for example, the electric motor is coupled to a drive wheel of the motor vehicle, in particular by means of a shaft. For example, the electric motor is designed as a so-called hub motor. Alternatively, by means of the electric motor, for example, a gear is driven, which is coupled to the drive wheel.

The converter is coupled in the assembled state with a vehicle electrical system of the motor vehicle, by means of which in particular a DC electrical voltage is provided. For example, the electrical system is a low-voltage electrical system, with which an electrical voltage of 12 volts, 24 volts or 42 volts is provided. Alternatively, the electrical system is a high-voltage electrical system in which, for example, an electrical voltage between 400 volts and 1,000 volts and, for example, provided substantially 800 volts. The inverter has an intermediate circuit capacitor and an inverter. Particularly preferably, the DC link capacitor is powered by the electrical system. The DC link capacitor has two electrodes, one of which is electrically contacted with different potentials of the electrical system. By means of the intermediate circuit capacitor, an energy store is suitably provided.

The inverter is electrically arranged between the electric motor and the DC link capacitor. In other words, the inverter is between the electric motor and the DC link capacitor electrically connected. Consequently, the inverter is electrically contacted with the electric motor and electrically with the DC link capacitor. In particular, the DC link capacitor is directly electrically contacted with the inverter, so that there are no other electrical components between them. The inverter includes, for example, a semiconductor switch, preferably a number of such semiconductor switches, by means of which an electrical current flow between the DC link capacitor and the electric motor is adjusted during operation. The semiconductor switch is in particular a transistor, preferably a field-effect transistor, for example a MOSFET, a GTO or an IGBT. The semiconductor switch is preferably electrically contacted with a control unit of the inverter, wherein in operation by means of the control unit, a state of the semiconductor switch is set, so whether it is electrically conductive or electrically non-conductive.

Thus, during operation, the electric motor is driven by means of the converter, wherein, for example, electrical energy is taken from the eventual vehicle electrical system and supplied to the electric motor. Particularly preferably, the inverter is regenerative capable, so that in particular at a deceleration of the motor vehicle, the electric motor acts as a generator and the electrical energy generated in this way is used to power the DC link capacitor means of the inverter. In other words, the inverter is designed to be regenerative.

Furthermore, the drive has two feedthrough contactors. In this case, in each case one of the feedthrough capacitors is associated with one of the electrodes of the intermediate circuit capacitor, and each of the two electrodes is guided by means of the associated feedthrough capacitor to ground. In other words, each of the feedthrough capacitors in each case has two electrodes, wherein one of the electrodes of the feedthrough capacitor is electrically contacted with the electrode of the respective intermediate circuit capacitor. The remaining electrodes of the two feedthrough capacitors are electrically connected to ground, in particular directly. Preferably, the electrodes of the DC link capacitors are preferably electrically contacted directly with the respective associated electrode of the DC link capacitor. In other words, no further electrical and / or electronic component is electrically connected between the two electrodes. Mass is provided for example by means of a body of the motor vehicle. In other words, each of the feedthrough capacitors is electrically contacted with the body, which simplifies cabling.

Due to the feedthrough capacitors filtering takes place of the inverter taken or back acting on these electrical currents, which is why an electromagnetic compatibility is increased. The feedthrough capacitors do not require any printed circuit boards or the like for mounting and can thus be positioned comparatively freely. As a result, only comparatively few mounting components for stabilizing and positioning the feedthrough capacitors are required, which reduces manufacturing costs. Also, a space requirement is reduced, which is why a comparatively compact drive is realized. Also, due to the increased electromagnetic compatibility by means of feedthrough capacitors, no additional measures or at least only a small amount of additional measures for realizing a given electromagnetic compatibility are required, which further reduces manufacturing costs.

For example, each of the feedthrough capacitors has a current carrying capacity of 1 ampere to 5,000 ampere and, for example, between 10 ampere and 2,000 ampere or between 100 ampere and 1,000 ampere. In particular, the capacitance of each of the feedthrough capacitors is less than 0.1 μF and, for example, greater than 1 nF. In particular, the capacitance of each of the feedthrough capacitors is substantially equal to 0.01 μF. Particularly preferably, the feedthrough capacitors are identical to one another, which reduces manufacturing costs and simplifies storage.

Advantageously, the intermediate circuit capacitor and the inverter are electrically contacted by means of two bus bars. The busbars are in particular electrical lines. For example, only the two busbars are electrically connected between the intermediate circuit capacitor and the inverter. The busbars are provided for example by means of a stamped and bent part, which is essentially made for example of a copper, in particular pure copper or a copper alloy. The stamped and bent parts are designed, for example, substantially cuboid. Preferably, each of the busbars comprises at least one such stamped and bent part and / or, for example, a cable. For example, the busbars each have a shield, in particular a wire mesh, by means of which, for example, a core, such as the (supporting) body or a strand is surrounded. The shield is guided, for example, to ground, so that a radiation of electromagnetic waves is prevented by the busbar due to an alternating current flowing through here, which further increases electromagnetic compatibility. Each electrode of the DC link capacitor is each associated with one of the busbars, so that the busbar preferably has the same electrical potential as the respective associated electrode of the intermediate circuit capacitor.

Each of the bus bars preferably has one of the feedthrough capacitors in each case. In other words, the busbar is at least partially formed by means of the feedthrough capacitor, wherein the busbar there preferably has a cuboid-shaped body, which is peripherally surrounded by a coil, which forms, for example, the further electrode. The body is for example the stamped and bent part. Particularly preferably, the feedthrough capacitor has two (condenser) windings, which are spaced apart from one another and configured in a spiral or helical shape and engage in one another. As a result, an effective overlap area of the two capacitor windings is increased. Suitably, the capacitor windings are arranged coaxially with the body. One of the capacitor winding is electrically connected to ground and the other electrically connected to the (busbar / support) body, which preferably has the same electrical potential as the respectively associated electrode. Since the busbar has both the feedthrough capacitor and the electrical contacting of the inverter is used with the DC link capacitor, a space requirement is further reduced. Also, the feedthrough capacitor is stabilized.

Particularly preferably, the inverter and the electric motor are each designed in three phases. In other words, the electric motor has three phases, which in particular are energized successively during operation. For example, each phase has an electromagnet, preferably in each case a number of electromagnets. Suitably, each of the phases of the electric motor has the same number of electromagnets. The inverter preferably has a bridge circuit, which in particular comprises three bridge branches. Each of the bridge branches preferably has two semiconductor switches. In other words, the inverter is built in a B6 configuration. For example, each one of the phases of the electric motor is electrically contacted with one of the bridge branches.

The intermediate circuit capacitor is preferably connected in parallel with the bridge branches. For example, the inverter and the intermediate circuit capacitor are electrically contacted by means of the busbars, wherein the two busbars are electrically connected to each other by means of the bridge branches, which are connected in parallel with each other. For example, the drive has a total of six busbars, wherein each of the bridge arms are each assigned two busbars.

Preferably, each of the busbars each have a feedthrough capacitor, so that the drive has a total of six feedthrough capacitors. As a result, it is possible to reduce the capacity of the respective feedthrough capacitors, which further reduces the installation space of the feedthrough capacitors and their cost.

For example, the phases of the electric motor are connected to one another in a delta connection. Particularly preferably, however, the phases of the electric motor are connected to form a star connection with each other. In other words, each of the phases of the electric motor is electrically contacted both with the inverter, in particular with a bridge branch of the inverter, and with a common star point. The star point is expediently not electrically contacted with a further electrical potential, and in particular not electrically connected to a housing and / or ground. Preferably, the star point is "floating". Due to stray capacitances of the electric motor common mode with common mode currents are caused during operation. The common mode currents have comparatively short rise and fall times and, for example, between 5A and 20A in the peak. The level of the (common mode) currents is dependent, in particular, on a switching speed of the inverter, in particular on a switching speed of its semiconductor switches / switching elements, and on other characteristics of the noise current circuit. By means of the feedthrough capacitors for the electric current, in particular the common mode currents, a broadband low-impedance path exists, which reduces the common mode noise. In summary, in particular by means of the feedthrough capacitors, the electric current, in particular the common-mode currents, a low-impedance return path to the intermediate circuit capacitor is made possible. This prevents comparatively large (electrical) common-mode voltages between the potentials of the vehicle electrical system, in particular any battery terminals, and ground and / or between the electrodes of the DC link capacitor and ground. Thus, a low electromagnetic compatibility (EMC) is possible.

For example, the DC link capacitor and the inverter are arranged in a common housing. However, particularly preferably, both the DC link capacitor and the inverter each have a housing. In other words, the inverter is modular, which simplifies assembly and further reduces manufacturing costs. The housing of the inverter and / or the housing of the intermediate circuit capacitor are made for example of a metal which is electrically contacted with ground. Thus, an electromagnetic compatibility (EMC) of the inverter is further increased.

For example, the housing of the DC link capacitor is connected to the housing of the inverter, so that they are stabilized to each other. Particularly preferably, however, the two housings are spaced apart from one another so that they can be positioned comparatively independently of one another, which is why an installation space in the motor vehicle can be utilized comparatively efficiently. In this case, the intermediate circuit capacitor and the inverter are particularly preferably electrically connected to one another by means of the busbars, which are configured, for example, at least in sections in the manner of a cable

For example, the feedthrough capacitors are integrated in at least one housing of the drive, for example in the housing of the intermediate circuit capacitor. In other words, the respective feedthrough capacitor is stabilized with the respective housing. For example, the bus bars on the feedthrough capacitor, which are arranged in an opening through the housing. For example, the feedthrough capacitor is screwed to the respective housing or arranged in an opening of the housing, so that the feedthrough capacitor protrudes through the opening and is thus arranged at least partially within and partially outside of the respective housing.

In other words, the feedthrough capacitor is attached to a wall of the respective housing. Preferably, the wall, preferably the complete housing, is electrically grounded and one of the electrodes of the respective feedthrough capacitor is electrically contacted to the housing. As a result, an assembly is further simplified and there are no further components required, which further reduces manufacturing costs. Particularly preferably, the feedthrough capacitors are integrated in the housing of the inverter. Thus, an electrical path between the potential semiconductor switches of the inverter and the feedthrough capacitors is reduced, and therefore any disturbances caused due to switching operations of the inverter's semiconductor switch (s) are relatively efficiently filtered by the feedthrough capacitors. Therefore, propagation to other components of the drive or the motor vehicle is prevented. Also, an effective length of the noise-bearing components of the drive is reduced, and therefore radiation of electromagnetic waves is reduced.

For example, the feedthrough capacitors between the inverter and the DC link capacitor, in particular between the housings, arranged, wherein the bus bar, for example, have the feedthrough capacitors. Suitably, the drive comprises a clip which is electrically grounded. Since the clasp is grounded, electrical insulation is not required, further reducing manufacturing costs. With the clasp, which is provided for example by means of a metal strip or the like, in each case one electrode of the two feedthrough capacitors is electrically contacted. In other words, in each case one of the electrodes of the two feedthrough capacitors is electrically contacted with the clip.

For example, the feedthrough capacitors are X capacitors. In other words, the feedthrough capacitors are suppression capacitors for Class X interference suppression according to IEC 60384-1. Particularly preferred, however, are the feedthrough capacitors class Y capacitors according to IEC 60384-1, which thus bridge in particular a basic insulation. For example, the capacitors are Y2 capacitors. Therefore, safety of the drive is further increased. Furthermore, the feedthrough capacitors serve to suppress common-mode noise, which arises in particular due to the coupling of the phases of the electric motor to ground due to parasitic capacitances (stray capacitances).

The drive, for example the converter, particularly preferably has an EMC filter. Conveniently, the EMC filter comprises a connection for the eventual electrical system of the motor vehicle, and the vehicle electrical system of the motor vehicle is expediently electrically contacted in the assembled state with the EMC filter, in particular directly connected to this. The DC link capacitor is electrically arranged between the EMC filter and the inverter. Preferably, a terminal of the EMC filter is electrically contacted with one of the electrodes of the DC link capacitor and another terminal of the EMC filter with the other electrode of the DC link capacitor. By means of the EMC filter, for example, a high-pass and / or a low-pass filter are provided, by means of which disturbances are thus filtered. For example, the EMC filter has a throttle or the like. Due to the EMC filter, faults that occur due to any switching operations of the inverter are filtered out and not routed to the electrical system. Also, any faults in the vehicle electrical system are filtered out so that the inverter can be operated independently of such interference. Due to the feedthrough capacitors, it is possible to dimension the EMC filter comparatively small, which reduces manufacturing costs.

The motor vehicle has a drive with a brushless electric motor and with a converter. The inverter comprises a DC link capacitor with two electrodes and an inverter. The inverter is electrically arranged between the electric motor and the DC link capacitor, wherein the electrodes of the DC link capacitor are each guided by means of a feedthrough capacitor to ground. Preferably, the drive, for example, the inverter, electrically contacted with an electrical system of the motor vehicle, for example, a low-voltage electrical system or more preferably a high-voltage electrical system of the motor vehicle. The drive is, for example, a component of an accessory of the motor vehicle, such as a pump or a blower. However, the drive is particularly preferably a main drive. In this case, the motor vehicle has a drive wheel, which is in operation, for example, in direct mechanical contact with a substrate of the motor vehicle, for example a road. The drive wheel is driven by the electric motor. For this purpose, the electric motor in operative connection with the drive wheel and thus mechanically coupled thereto. Preferably, the motor vehicle has a number of such drive wheels, for example a total of two or four such drive wheels. In particular, the brushless electric motor is operated in a regenerative braking of the motor vehicle, wherein an electric energy provided in this way is stored by means of the intermediate circuit capacitor and / or fed into the eventual electrical system of the motor vehicle.

The refinements and advantages embodied in connection with the drive of a motor vehicle are also to be transferred analogously to the motor vehicle and vice versa.

• 1 schematisch ein Kraftfahrzeug mit einem Antrieb,
• 2 schematisch vereinfacht einen Schaltplan des Antriebs mit einem Zwischenkreiskondensator und mit einem Wechselrichter,
• 3 eine weitere Ausführungsform des Zwischenkreiskondensators und des Wechselrichters, und
• 4 einen Durchführungskondensator in einer Schnittdarstellung.

Embodiments of the invention will be explained in more detail with reference to a drawing. Show:

• 1 schematically a motor vehicle with a drive,
• 2 schematically simplifies a circuit diagram of the drive with a DC link capacitor and with an inverter,
• 3 a further embodiment of the DC link capacitor and the inverter, and
• 4 a feedthrough capacitor in a sectional view.

Corresponding parts are provided in all figures with the same reference numerals.

In 1 is schematically a side view simplified a motor vehicle 2 with a body 4 shown. The body 4 has mass as electrical potential 6 on. The car 2 includes two drive wheels 8th and two more wheels 10 of which only one is shown. The wheels 10 are located in a front area of the motor vehicle 2 and are designed steerable, and the drive wheels 8th form the two rear wheels of the motor vehicle 2 , By means of the drive wheels 8th and the wheels 10 is the body 4 spaced from a floor, not shown, in particular a road.

The car 2 has a high-voltage electrical system 12 on, which by means of a high-voltage battery 14 is fed, by means of which a DC electrical voltage of substantially 800 Volt is provided. The high voltage on-board network 12 is with a drive 16 electrically contacted, which consequently by means of the high-voltage vehicle electrical system 12 is fed. The drive 16 has an inverter 18 on, to the high-voltage on-board electrical system 12 electrically connected. By means of the inverter 18 is a brushless electric motor 20 operated, which in operative connection with the drive wheels 8th is. Consequently, by means of the inverter 18 a speed of the brushless electric motor 20 and thus a speed of the drive wheels 8th set, in particular regulated. As a result, an adjustment of the speed of the motor vehicle takes place 2 by means of the inverter 18 ,

In 2 schematically simplified is a wiring diagram of the inverter 18 having drive 16 shown. The inverter 18 has an EMC filter 22 with not shown filter components, such as capacitors and chokes. The EMC filter 22 This forms the connection of the drive 16 to the high-voltage electrical system 12 , The EMC filter 22 has two outputs 24 on, each with an input 26 a DC link capacitor 28 of the inverter 18 are electrically contacted, the two outputs 30 having. Here is one of the inputs 26 of the DC link capacitor 28 each with one of the outputs 30 of the DC link capacitor 28 contacted directly electrically. Furthermore, the DC link capacitor 28 a capacity 32 on that electrically between the two outputs 30 and thus between the two entrances 26 is switched. The capacity 32 has two electrodes 33 each of which is electrically connected to one of the outputs 30 of the DC link capacitor 28 and with one of the inputs 26 of the DC link capacitor 28 is contacted.

The capacity 32 is inside a housing 34 of the DC link capacitor 28 arranged, which is made of a metal. Each of the outputs 30 of the DC link capacitor 28 is by means of a busbar 36 against an entrance 38 an inverter 40 led, which is a housing 42 has, which is made of a metal. Thus, the DC link capacitor 28 electrically between the EMC filter 22 and the inverter 40 arranged.

The housing 34 of the DC link capacitor 28 is from the case 42 of the inverter 40 spaced. The housing 42 of the inverter 40 is electric with mass 6 contacted so that the electrical potential of the housing 42 Dimensions 6 equivalent. The busbars 36 run inside the housing 42 of the inverter 40 continue, so that through the entrances 38 of the inverter 40 protrude through.

Each of the busbars 36 has a feedthrough capacitor 44 on, which are identical and each have a capacity of 220nF exhibit. The feedthrough capacitors 44 here are Y2 capacitors. Each feedthrough capacitor 44 has two electrodes 46 one of which is the electrical potential of the respectively assigned input 38 of the inverter 40 and thus the electrical potential of one of the electrodes 33 of the DC link capacitor 28 having. The remaining of the electrodes 46 each feedthrough capacitor 44 is electrically directly to the housing 42 of the inverter 40 contacted, so this as an electrical potential mass 6 having. Therefore, the two electrodes 33 of the DC link capacitor 28 by means of a feedthrough capacitor 44 against mass 6 guided, namely on the housing 42 of the inverter 40 , Additionally, each of the feedthrough capacitors configured as Y2 capacitors has 44 a third surface (electrode) not shown in detail, in particular between the two electrodes 46 the respective feedthrough capacitor 44 is arranged, and for example, not electrically contacted and / or "floating". Each of the feedthrough capacitors 44 that is schematically inside the housing 42 of the inverter 40 shown are the inputs 38 of the inverter 40 and are thus inside the case 42 of the inverter 40 arranged and integrated in this. In an alternative, the feedthrough capacitors 44 at least at the respective entrance 38 placed. In another variant, not shown, the feedthrough capacitors 44 completely inside the case 42 of the inverter 40 arranged and are for example of any walls of the housing 42 spaced. Appropriately, in this case, several feedthrough capacitors 44 used.

Between the two busbars 36 are three parallel bridge branches 48 connected, which are identical to each other and two series-connected semiconductor switch 50 in the form of IGBT's. Between the semiconductor switches 50 every bridge branch 48 is with the bridge branch 48 each one of the three phases 52 of the brushless electric motor 20 contacted. Consequently, the inverter points 40 a B6 configuration, and the inverter 40 is electrically between the electric motor 20 and the DC link capacitor 28 arranged. The from the inverter 40 to the electric machine 20 flowing electrical currents have a strength between 100 A and 1000 A during operation.

The phases 52 of the brushless electric motor 20 are interconnected in a star connection. In other words, each of the phases 52 against a star point 54 guided and thus contacted each other electrically. The star point 54 is in particular electrically floating In summary, both the inverter 40 as well as the (brushless) electric motor 20 three-phase.

In 3 is a modification of the drive 16 shown. Here is the DC link capacitor 28 modified and has a total of six exits 30 on each of which three are electrically connected to one of the electrodes 33 and the remaining three outputs 30 with the other of the two electrodes 33 electrically contacted directly. There are a total of six busbars 36 present, which run parallel to each other, and two of which each one of the bridge branches 48 assigned. The busbars 36 are parallel to each other and are equipped with a clasp 56 spanned from a sheet metal, from the busbars 36 is spaced.

The drive 16 also has a total of six feedthrough capacitors 44 on, with each of the busbars 36 again one of the feedthrough capacitors 44 includes. One of the electrodes 46 each feedthrough capacitor 44 is electric with the clasp 56 contacted, which with mass 6 is contacted. The clasp 56 is created for example from a tinned sheet metal. The feedthrough capacitors 44 have a capacitance of 68 nF and are in turn designed as Y2 capacitors.

In 4 is one of the feedthrough capacitors 44 shown in a longitudinal section. The busbar 36 has a (supporting) body 58 on, which is made of a copper and electrically connected to the output of the DC link capacitor 30 is contacted. The body 58 is configured, for example cuboid and a stamped and bent part. On the body 58 is frictionally peripherally a first spring contact 60 which is electrically connected to one of the electrodes 46 of the pass capacitor 44 is contacted. The electrode 46 the feedthrough capacitor 44 is spiraling around the body 58 wound. The remaining (second) electrodes 46 is also spiral around the body 58 twisted and reaches into the other electrode 46 the feedthrough capacitor 44 one, with the two electrodes 46 spaced apart from each other. The two electrodes 46 the feedthrough capacitor 44 are thus formed as a so-called capacitor winding. The second electrode 46 of the pass capacitor 44 is by means of a second spring contact 62 , the end face of this electrode 46 Tailed, with a shroud 64 contacted, which is perpendicular to the body 58 is arranged. The body 58 protrudes through the shielding plate 54 through and is spaced from this.

In a further embodiment, the shield plate 64 with the housing 42 of the inverter 42 educated. The feedthrough capacitor 44 also has a sleeve 66 on, which is made of a plastic, and by which the body 58 runs. This engages the sleeve 66 between that on the body 58 fitting first spring element 60 and the electrodes 46 one. In addition, the sleeve 66 end a number of locking hooks 68 on that with the shroud 64 are locked. By means of the locking hooks 68 is a detachment of the spring contact 62 from the shroud 64 avoided. In addition, by means of the sleeve 66 an electrical insulation of the body 58 opposite the shielding plate 64 ,

In summary, especially in the busbars 36 integrated feedthrough capacitors 44 used to filter EMC interference. Due to the integration in the busbars 36 This eliminates the cost of an additional circuit board, and due to the reduced series inductance, the filtering effect of the individual feedthrough capacitors 44 elevated. Here are the feedthrough capacitors 44 preferably designed as Y2 capacitors. In a variant, not shown, the clasp 56 in the DC link capacitor 28 or the inverter 40 integrated, creating an electrical path between the switches 50 and the respective feedthrough capacitor 44 is shortened.

In a further variant, not shown further low-impedance X capacitors are also present, these with the inputs 38 of the inverter 40 electrically contacted. In this way, a high frequency behavior is improved. Here, the X capacitors are designed such that they have a total impedance of the DC link capacitor 28 reduce broadband, especially in the megahertz range, for example in a frequency range between 50 kHz to 1800 kHz.

Due to the drive 16 is a low-impedance path for interference currents, which is why any interference voltages are reduced. This makes it possible to use a comparatively inexpensive EMC filter 22 yet comparatively low disturbances in the electrical system 12 be directed or emitted. The interference currents arise in this case, in particular due to stray capacitances, by means of the phases 52 are formed. In this case, by means of the feedthrough capacitors 44 that also with mass 6 are electrically contacted, the parasitic currents on the capacity 33 of the DC link capacitor 28 so that there is a common mode noise due to the Y2-type feedthrough capacitors 44 is reduced.

The invention is not limited to the embodiments described above. Rather, other variants of the invention can be derived therefrom by the person skilled in the art without departing from the subject matter of the invention. In particular, all the individual features described in connection with the individual embodiments are also combinable with one another in other ways, without departing from the subject matter of the invention

LIST OF REFERENCE NUMBERS

2

motor vehicle

4

body

6

Dimensions

8th

drive wheel

10

wheel

12

High-voltage onboard network

14

High-voltage battery

16

drive

18

inverter

20

(brushless) electric motor

22

EMC filters

24

Output of the EMC filter

26

Input of the DC link capacitor

28

Link capacitor

30

Output of the DC link capacitor

32

Capacity of the DC link capacitor

33

electrode

34

Housing of the DC link capacitor

36

conductor rail

38

Input of the inverter

40

inverter

42

Housing of the inverter

44

Through capacitor

46

Electrode of the feedthrough capacitor

48

bridge branch

50

Semiconductor switches

52

phase

54

star point

56

clasp

58

body

60

first spring contact

62

second spring contact

64

shroud

66

shell

68

latch hook

Claims (9)

Drive (16) of a motor vehicle (2) with a brushless electric motor (20), and with an inverter (18) having a DC link capacitor (28) comprising two electrodes (33) and an inverter (40), wherein the inverter ( 40) is electrically arranged between the electric motor (20) and the intermediate circuit capacitor (28), and wherein the electrodes (33) of the intermediate circuit capacitor (28) are each guided by means of a feedthrough capacitor (44) to ground (6). Drive (16) to Claim 1 , characterized in that the intermediate circuit capacitor (28) and the inverter (40) by means of two bus bars (36) are electrically contacted with each other, each bus bar (36) each having one of the feedthrough capacitors (44). Drive (16) to Claim 1 or 2 , characterized in that the inverter (40) and the electric motor (20) are three-phase. Drive (16) to Claim 3 , characterized in that the phases (52) of the electric motor (20) are connected to a star connection with a neutral point (54). Drive (16) after one of Claims 1 to 4 , characterized in that the intermediate circuit capacitor (28) and the inverter (40) each have a housing (34, 42) which are spaced from each other. Drive (16) to Claim 5 , characterized in that the feedthrough capacitors (44) are integrated in the housing (42) of the inverter (40). Drive (16) after one of Claims 1 to 6 , characterized in that the feedthrough capacitors (44) are Y2 capacitors. Drive (16) after one of Claims 1 to 7 characterized by an EMC filter (22), wherein the DC link capacitor (28) is electrically disposed between the EMC filter (22) and the inverter (40). Motor vehicle (2) with a drive (16) according to one of Claims 1 to 8th , wherein in particular a drive wheel (8) by means of the electric motor (20) is driven.

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