DE102020105554A1 - At least six-phase inverter, electric drive unit and motor vehicle - Google Patents

Abstract

The invention relates to an at least six-phase inverter (3) for an electric drive unit (1) of a motor vehicle, comprising: - inverter electronics (12) with - at least two converter circuits (18) for converting a direct signal into alternating signals for phase connections of an electric drive machine (2 ) the drive unit, - a DC connection panel (19) with DC connection points (22a, 22b) electrically connected on the input side to the converter circuits (18) for supplying the DC signal and - at least two AC connections electrically connected to the output side with the converter circuits (18) -Connection panels (28) for supplying the alternating signals to the phase connections, - a carrier (10) for the inverter electronics (12), and- a cover (11), which with the carrier (10) forming a housing end part (7) for receiving the inverter electronics (12) is connected, wherein the housing end part (7) with a central housing (5) for receiving the electric drive machine (2) ve rbindbar and wherein when joining the housing end part (7) with the central housing (5), the AC plug contacts (30a, 30b, 30c) can be plugged together with the phase connections.

Description

The invention relates to an at least six-phase inverter for an electric drive unit of a motor vehicle. The invention also relates to an electric drive unit and a motor vehicle.

In the present case, interest is directed towards electrically powered vehicles, i.e. hybrid or electric vehicles. Such motor vehicles have an electric drive train with an electric drive unit and an energy supply device, for example a traction battery. The drive unit usually has an electric drive machine and an inverter or converter, which converts the direct signal provided by the traction battery, ie a direct current and a direct voltage, into an alternating signal, ie an alternating current and an alternating voltage.

Since there is often only limited installation space available in the motor vehicle, the inverter is often costly and laboriously adapted and redesigned so that it fits into the available installation space. For example, the inverter can be arranged above the drive machine, perpendicular to an axis of rotation of the drive machine. When the drive unit is installed in the motor vehicle, the drive machine and the inverter are thus arranged one above the other along a vertical axis of the vehicle. In the event that the drive unit drives a rear axle of the motor vehicle, volume of the vehicle trunk is lost in an undesirable manner. In the event that the drive unit drives a front axle of the motor vehicle, the inverter consumes integration volume for control units of the motor vehicle. In addition, the assembly or fastening of the inverter in the motor vehicle is associated with a high expenditure of time and money. The inverter is usually screwed on, for which a large number of screws are necessary, which have to be attached by assembly personnel in a laborious manner.

It is the object of the present invention to provide an inexpensive inverter that can be installed simply and in a space-saving manner.

According to the invention, this object is achieved by an inverter, an electric drive unit and a motor vehicle having the features according to the respective independent claims. Advantageous embodiments of the invention are the subject matter of the dependent claims, the description and the figures.

An at least six-phase inverter according to the invention for an electric drive unit of a motor vehicle has inverter electronics. The inverter electronics have at least two converter circuits for converting a direct signal into alternating signals for phase connections of an electric drive machine of the drive unit. In addition, the inverter electronics have a DC connection field with DC connection points electrically connected to the converter circuits on the input side. Furthermore, the inverter electronics have at least two AC connection fields, each electrically connected to the converter circuits on the output side, each with three AC plug contacts. The DC signal can be fed to the converter circuits via the DC connection points. The alternating signals can be fed to the phase connections via the AC plug contacts.

The inverter also has a carrier for the inverter electronics and a cover which is connected to the carrier to form a housing end part for receiving the inverter electronics. The converter circuits are arranged between the at least two AC connection panels so that AC signal paths between the converter circuits and the respective AC plug contacts are essentially of the same length. The DC connection points are positioned in relation to the converter circuits in such a way that DC signal paths between the DC connection points and the respective converter circuit are essentially of the same length. The AC plug contacts are passed through the carrier. The housing end part can be connected to a central housing for accommodating the electric drive machine, with the AC plug contacts being able to be plugged together with the phase connections of the electric drive machine when the housing end part is joined to the central housing.

The invention also relates to an electric drive unit for a motor vehicle with an electric drive machine, a central housing in which the electric drive machine is arranged, and an inverter according to the invention. The central housing for the drive machine and the housing end part of the inverter are joined together axially along an axis of rotation of the electric drive machine. The housing end part of the inverter forms a cover for the central housing. The phase connections of the drive machine are plugged together with the AC plug contacts. The electric drive machine has, in particular, a stator, which carries phase windings or stator windings, and a rotor, which is non-rotatably connected to a rotor shaft. The central housing encases the hollow cylindrical stator and extends axially along a length of the stator parallel to the axis of rotation or longitudinal axis of the electric drive machine. In addition, the electric drive unit can have a transmission, which in another Housing end part is arranged, wherein the housing end part of the inverter, the central housing for the drive machine and the further housing end part for the transmission are axially joined together to form an overall housing of the electric drive unit. The central housing is arranged between the two housing end parts. The two housing end parts are arranged on the side of the central housing.

The housing end part of the inverter has the carrier and the cover, which can be made of aluminum, for example. In the assembled state of the housing end part and the central housing, a surface of the carrier is oriented perpendicular to the axis of rotation of the drive machine. When the drive unit is installed in the motor vehicle, the axis of rotation is oriented perpendicular to a vertical axis of the motor vehicle and along a transverse axis of the vehicle, so that the inverter is arranged on the side of the drive machine. When the drive unit is installed, the inverter is therefore not arranged along the vertical axis of the vehicle above the drive machine. This results in the advantage that free installation space is available above the drive machine, which space can be used, for example, for the vehicle trunk and / or control units of the motor vehicle.

The carrier and the cover form a receiving space between them in which the inverter electronics are arranged. The inverter electronics are designed to convert the direct signal in the form of a DC current or direct current and a direct voltage into alternating signals, i.e. AC currents or alternating currents and alternating voltages, for the phase windings of the drive machine. The DC signal is provided by an energy supply device, for example a rechargeable traction battery in the form of a high-voltage storage device, of the motor vehicle and fed to the inverter via the DC connection panel. The converter circuits convert the direct signal into alternating signals and provide the alternating signals to the AC plug contacts of the AC connection panels. The inverter and the drive machine are designed to have at least six phases. The electric drive machine therefore has at least two phase connection sets, each with three phase connections, each phase connection set being electrically connected to an AC connection field of the inverter. The inverter is designed in such a way that the electrical connection can be established by axially attaching the housing end part in which the inverter electronics are arranged to the central housing. During the attachment, the AC plug contacts of the inverter are plugged together with the phase connections of the electric drive machine. For this purpose, the carrier has, for example, through openings through which the AC plug contacts are passed and are therefore accessible from the outside.

The converter circuits have, for example, a switching unit or a switching module with semiconductor switches and an intermediate circuit unit with capacitors. In particular, the converter circuits are of identical construction and are positioned symmetrically to one another on the carrier. Since the inverter and the drive machine are designed to have at least six phases, signal values and thus losses per phase are reduced compared to a three-phase inverter and a three-phase drive machine. The semiconductor switches and the capacitors are therefore designed in particular as discrete components which are inexpensive and have a high level of availability. The multi-phase nature enables the use of thinner signal paths, for example rails or plates. The switching unit of a converter circuit has, in particular, three half bridges, each with two semiconductor switches. Each half bridge is connected to one of the AC plug contacts on the AC connection panel. For example, each AC connection field has three AC busbars, which are connected at one end to AC power terminals of the respective half bridges and have the AC plug contacts at another end. The AC busbars form the AC signal paths.

The converter circuits, the AC connection fields and the DC connection points are positioned in relation to one another in the housing end part in such a way that an essentially symmetrical structure of the inverter electronics results. For example, the switching units are arranged between the AC connection panels and the intermediate circuit units and the DC connection points are arranged between the two switching units. For example, the half bridges of a converter circuit are arranged in a row, the associated connection field being arranged next to the row with the half bridges. In the case of two converter circuits, the two rows are arranged at a distance from one another with half bridges, the capacitors and the DC connection points being arranged between the two rows. The capacitors of a converter circuit can, for example, also be arranged in a row and be arranged with half bridges next to the associated row. The intermediate circuit units and the DC connection points are arranged in the center of the carrier, the switching units are arranged to the right and left of the intermediate circuit units and the DC connection points, and the AC connection panels are arranged to the right and left of the switching units.

Starting from the DC connection points, the DC signal is sent to the DC link units and via the DC signal paths of the same length fed to the switching units. There the direct signal is converted into the respective alternating signals. These alternating signals are then fed to the AC plug contacts via the AC signal paths of the same length. The essentially equally long signal paths can ensure that a simultaneous and offset-free signal transmission or current transmission to the phase connection sets of the electric drive machine takes place.

It proves to be advantageous if the DC connection field has DC contact elements which are passed through the carrier and can be connected to an inverter-external, central housing-integrated DC filter when the housing end part is joined to the central housing. The DC connection field preferably has DC current conductors, for example DC busbars, which are connected at one end to the DC contact elements and form the DC connection points at their other end. In an advantageous embodiment of the electric drive unit, the central housing has a shaft extending axially along the axis of rotation in which the DC filter is arranged, the DC filter in the assembled state of the central housing with the housing end part of the inverter with the DC connection panel of the Inverter is electrically connected. The inverter itself is therefore designed without a filter. The DC filter has been moved to the outside, resulting in a particularly compact inverter with a flat design, which can be arranged on the electric drive machine in a space-saving manner. The DC filter extends along the axis of rotation of the drive machine over the length of the stator in the shaft of the central housing. When the drive unit is installed in the motor vehicle, the DC filter is arranged in an accident-protected area, that is, in the “crash shadow” of the drive unit. In addition, the shaft in the metallic central housing acts as a very good electromagnetic shield, so that no magnetic interference radiates outward into the motor vehicle. Components of the DC filter also have a ground connection to the massive central housing by means of screws or spring contacts

In this case, the DC filter is electrically connected to the DC connection panel at a first end which faces the housing end part of the inverter. At a second end, which faces away from the housing end part, the DC filter is connected, for example, to a DC plug connector. This can be plugged together with a DC connector of the energy supply device. The DC filter prevents retroactive magnetic interference from the inverter in the battery. An EMC measure for damping disturbances in the flow of AC current is preferably arranged between the inverter and the central housing. For example, the EMC measure can have an iron core which is screwed tightly to the central housing.

It can be provided that the inverter has a circuit carrier on which the converter circuits are arranged, with a respective AC power terminal of the half bridges overlapping with a respective AC power rail of the AC connection panel and being electrically and electrically connected to the AC power rail by means of laser welding is mechanically connected. Alternatively, the AC power terminals and AC busbars can be bent and connected with pliers using resistance welding. The circuit carrier has, in particular, a plastic layer which faces the carrier, so that electrical insulation is formed to avoid air and creepage distances.

The AC plug contacts arranged on the AC busbars protrude in particular from the side of the plastic carrier. The plastic carrier is then positioned on the carrier of the housing end part, the AC plug contacts being arranged in the through openings of the carrier. By establishing the electrical connection between the AC busbars and the AC current terminals by means of laser welding or resistance welding, expensive screws and their complex assembly can advantageously be dispensed with. In addition, the transfer resistance is almost zero. Assembly time is extremely reduced by laser welding or resistance welding.

In a further development of the inverter, the DC connection field has an electrode stack with a plate-shaped first electrode and a plate-shaped second electrode, the electrode stack being arranged so as to cover the converter circuits and wherein each electrode of the electrode stack is electrically connected to one of the DC connection points and to the converter circuits is. The first, for example positive, electrode and the second, for example negative, are in particular thin, rectangular copper plates, which are stacked on top of one another, insulated from one another. For example, a plastic layer can be arranged between the plate-shaped electrodes for electrical insulation. The plate-shaped electrodes are arranged on the carrier in such a way that they cover the converter circuits. The converter circuits are also covered by an insulation layer, with the exception of connection points for electrical connection to the electrodes. The plate-shaped electrodes form the DC signal paths or current paths between the DC connection points and the converter circuits. For this purpose, in particular over a complete length of the plate-shaped electrodes are those in two rows arranged capacitors connected to the plate-shaped electrodes, for example by laser welding or soldering. Such large-area signal paths can advantageously result in a particularly low-loss signal transmission to the converter circuits. In addition, the smaller distance and the flat design between the “plus” plate and the “minus” plate enable low inductance and thus low losses.

The inverter preferably has a circuit board with a control device for controlling the converter circuits, the circuit board being arranged so as to overlap with the electrode stack. An EMC (electromagnetic compatibility) protective layer, which is made in particular of aluminum or steel, is preferably arranged between the electrode stack and the circuit board. The control device has, in particular, a driver and control circuit for controlling the switching units. The control device can also have an evaluation unit which is connected, for example, via a communication link to diagnostic sensors of the inverter electronics, for example current sensors, and is designed to evaluate measurement signals from the diagnostic sensors. The circuit board with the control device is covered in particular by a protective cover. The converter circuits, the electrode stack, the EMC protective layer, the circuit board with the control device and the protective cover are stacked on top of one another between the carrier and the cover of the housing end part.

In an advantageous development of the invention, the inverter also has an angular position encoder for measuring a position of the rotor of the electric drive machine, the angular position encoder being at least partially passed through the carrier and, when the housing end part is joined to the central housing, on a rotor shaft of the drive machine connected to the rotor is positionable. Measurement signals from the angular position encoder can be fed to the control device of the inverter via a communication link. Because the housing end part with the inverter electronics is positioned axially to the drive machine and thus in alignment with the drive shaft, the angular position encoder can be integrated directly into the inverter. In this way, the evaluation unit of the control device can advantageously also be used for evaluating the measurement signals without long and complex communication paths to be provided. For example, a through opening can be provided in the carrier, through which the angular position encoder is at least partially guided out of the housing end part and is thus positioned on the rotor shaft in the assembled state of the housing end part and the central housing.

It is also advantageous if the housing end part has cooling ribs for passive cooling and / or cooling channels through which a cooling fluid can flow for active cooling of the inverter electronics. For example, the cooling fins can be used to cool the AC connection panels. For this purpose, the cooling fins can be arranged on the cover or can be formed in one piece with the cover. The cooling channels can be used, for example, to cool the capacitors and run over the capacitors.

The invention also relates to a motor vehicle with an electric drive unit according to the invention. The electrically drivable motor vehicle is designed in particular as a passenger vehicle. The axis of rotation of the electric drive machine of the drive unit is oriented parallel to a transverse direction of the vehicle.

The embodiments presented with reference to the inverter according to the invention and their advantages apply accordingly to the electric drive unit according to the invention and to the motor vehicle according to the invention.

Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination, but also in other combinations or on their own.

• 1 eine schematische Darstellung einer Antriebseinheit für ein elektrisch antreibbares Kraftfahrzeug aus einer ersten Perspektive;
• 2 die Antriebseinheit aus einer zweiten Perspektive;
• 3 eine schematische Darstellung einer ersten Schicht einer Inverterelektronik eines Inverters der Antriebseinheit;
• 4 eine schematische Darstellung einer Wandlerschaltung der Inverterelektronik auf einem Kunststoffträger;
• 5 eine schematische Darstellung einer zweiten Schicht der Inverterelektronik;
• 6 eine schematische Darstellung einer dritten Schicht der Inverterelektronik;
• 7 eine schematische Darstellung einer vierten Schicht der Inverterelektronik; und
• 8 eine schematische Darstellung einer fünften Schicht der Inverterelektronik.

The invention will now be explained in more detail using a preferred exemplary embodiment and with reference to the drawings. Show it:

• 1 a schematic representation of a drive unit for an electrically drivable motor vehicle from a first perspective;
• 2 the drive unit from a second perspective;
• 3 a schematic representation of a first layer of inverter electronics of an inverter of the drive unit;
• 4th a schematic representation of a converter circuit of the inverter electronics on a plastic carrier;
• 5 a schematic representation of a second layer of the inverter electronics;
• 6th a schematic representation of a third layer of the inverter electronics;
• 7th a schematic representation of a fourth layer of the inverter electronics; and
• 8th a schematic representation of a fifth layer of the inverter electronics.

Identical and functionally identical elements are provided with the same reference symbols in the figures.

1 and 2 show an electric drive unit 1 for an electrically powered motor vehicle from different perspectives. The electric drive unit 1 has an electric prime mover 2 , an at least six-phase inverter 3 as well as a transmission 4th on. The prime mover 2 is in a central housing 5 arranged the transmission 4th is in a first housing end part 6th arranged and the inverter 3 has a second housing end part 7th on, in which an inverter electronics is arranged. The central housing 5 and the housing end parts 6th , 7th form an overall housing 8th the electric drive unit 1 off, with the central housing 5 between the housing end parts 6th , 7th is arranged. The first housing end part 6th , the central housing 5 and the second housing end part 7th are so, as in 1 shown axially along an axis of rotation R of the electric drive machine 2 put together. The first housing end part 6th and the second housing end part 7th form covers for the central housing 5 the end. In 2 is the electric drive unit 1 in a plan view of the second housing end part 7th shown. This is where the central housing points 5 also a protective shield 9 on, which is in front of the second housing end part 7th is arranged and on which the second housing end part 7th , is attached, for example by screwing.

The second housing end part 7th has a carrier 10 (see e.g. 3 ) and a cover 11 on which a receiving space for receiving the inverter electronics 12th form. The one on the carrier 10 arranged inverter electronics 12th is in 3 until 8th shown. The carrier 10 and the cover 11 can for example be formed from aluminum. The cover 11 has cooling fins here 13th as well as cooling channels 14th for cooling the inverter electronics 12th on. The cooling channels 14th are with a cooling connection 15th of the housing end part 7th connected, over which the cooling channels 14th a coolant can be supplied.

The inverter 3 is designed to convert a direct signal into alternating signals for phase connections of the electric drive machine 2 to walk. The DC signal becomes the drive unit 1 via a DC connector 16 fed, which here on the part of the transmission 4th is arranged. The DC connector 16 can be electrically connected to a traction accumulator of the motor vehicle, not shown here, which provides the direct signal. The DC connector 16 is with a DC filter 17th the electric drive unit 1 electrically connected, which in turn is connected to the inverter 3 is electrically connected. The DC filter 17th is in a shaft here 46 of the central housing 5 arranged and thus extends along the axis of rotation R over a length of the central housing 5 . The DC filter 17th is therefore at the drive unit 1 not in the housing end part 7th of the inverter 3 integrated, but in the central housing 5 outsourced, so the inverter 3 can be made particularly compact and flat. The DC filter 17th avoids a retroactive magnetic disturbance of the inverter 3 into the battery.

In 3 until 8th are different layers of inverter electronics 12th shown. 3 shows two converter circuits 18th the inverter electronics 12th which are used to convert the direct signal into the alternating signals for the phase connections of the electric drive machine 2 are formed and which on the carrier 10 are arranged. The converter circuits 18th can also use the cooling channels 14th be cooled. The direct signal is supplied via a DC connection panel 19th into the inverter 3 fed in. The DC connection panel 19th has DC contact elements here 20a , 20b on which by the carrier 10 are passed through so that they are connected to the DC filter external to the inverter 17th can be electrically connected. In addition, the DC connection panel 19th DC current conductor 21a , 21b , for example DC busbars, which lead to DC connection points 22a , 22b are led. These DC connection points 22a , 22b are with the converter circuits 18th electrically connected.

The converter circuits 18th each have a switching unit 23 and an intermediate circuit unit 24 on. The switching units 23 each have three half bridges 25th with two semiconductor switches each 26th on. The three half bridges 25th a switching unit 23 are arranged in a row here. In addition, the rows are each with the three half bridges 25th arranged at a distance from one another and the intermediate circuit units 24 are between the half bridges 25th arranged. The DC link units 24 have capacitors 27 on, which are designed in particular as discrete components. The capacitors 27 in particular become passive with the cooling fins 23 chilled. contacted. The capacitors 27 an intermediate circuit unit 24 are also arranged in a row here, the rows with capacitors 27 side by side between the two rows with half bridges 25th are arranged. The converter circuits 18th are therefore arranged symmetrically to one another and constructed identically to one another. Also are the DC connection points 22a , 22b , which with the DC link units 24 be electrically connected, also between the two rows with half bridges 25th and in line with the capacitors 27 arranged.

The inverter electronics 12th also has two AC connection panels 28 each with an AC connection panel 28 with a converter circuit 18th is electrically connected and with a phase connection set of the electric drive machine 2 is electrically connectable. Any AC connection panel 28 is next to the associated converter circuit 18th arranged so that the AC connection panels 28 are arranged opposite one another and the converter circuits 18th are arranged in between. The AC connection panels 28 are also symmetrical to each other on the carrier 10 arranged and constructed identically to one another. The AC connection panels 28 each have three AC busbars 29a , 29b , 29c on which AC signal paths form. Corresponding signal paths of the two AC connection panels 28 are essentially the same length. So they are the first AC power rails 29a both AC connection panels 28 same length, second AC power rails 29b both AC connection panels 28 are the same length and third AC power rails 29c both AC connection panels 28 are the same length.

Any power rail 29a , 29b , 29c is on a first end with an AC power terminal 30a , 30b , 30c a half bridge 25th tied together. The electrical connection between the busbars 29a , 29b , 29c and the respective AC power terminals 30a , 30b , 30c is preferably made by laser welding. In addition, the AC connection panels 28 AC plug contacts 31a , 31b , 31c on which at a second end of the busbars 29a , 29b , 29c are arranged. The AC plug contacts 31a , 31b , 31c the AC connection panels 28 are thereby by the carrier 10 passed through. To this end, the carrier instructs 10 here through openings 32 into which the AC busbars 29a , 29b , 29c protrude in areas and into which the AC plug contacts 31a , 31b , 31c are arranged. By arranging the housing end part 7th on the central housing 5 are the AC plug contacts 31a , 31b , 31c with the phase connections of the respective phase connection set of the electric drive machine 2 plugged together and thereby electrically connected.

The carrier 10 also has a communication connection panel here 33 for a communication connection, for example with a control device external to the drive unit. The communication connection panel 33 can for example, as in 2 shown through the cover 11 be passed through. Furthermore, the carrier 10 a wing 34 on which the inverter electronics 12th is arranged, as well as a flange 35 with screw holes 36 on over which the cover 11 on the carrier 10 as well as the housing end part 7th on the central housing 5 can be attached. The inverter electronics 12th can be done directly on the wing 34 to be assembled. But it can also be like in 4th shown that the converter circuits 18th on a circuit carrier 37 , for example a plastic carrier, are mounted. Here is a plan view of an underside of the circuit carrier 37 shown which the wearer 10 is facing. Also are the AC connection panels 28 partially on the circuit carrier 37 arranged. The circuit carrier 37 has openings here 38 on which electrical contacts can be made using laser welding. For example, the AC busbars 29a , 29b , 29c with the AC power terminals 30a , 30b , 30c over the openings 38 be laser welded. In addition, the AC plug contacts are 31a , 31b , 31c on two opposite sides of the circuit board 37 arranged protruding so that they are when arranging the circuit carrier 37 on the carrier 10 in the through openings 32 of the wearer 10 can be arranged.

In 5 is another layer of inverter electronics 12th in the form of an electrode stack 39 shown. The electrode stack 39 is thereby overlapping with the converter circuits 18th arranged. Between the electrode stack 39 and the converter circuits 18th an insulation layer, not shown here, is arranged, which among other things in the area of the capacitors 27 and the DC connection points 22a , 22b Has openings so that electrodes 40a , 40b of the electrode stack 39 with the capacitors 27 and the DC connection points 22a , 22b , for example by laser welding or soldering, can be electrically connected. The electrodes 40a , 40b are plate-shaped and rectangular and stacked on top of one another in an electrically insulated manner. There is a first electrode 40a with a first DC connection point 22a as well as the capacitors 27 both converter circuits 18th and a second electrode 40b with a second DC connection point 22b as well as the capacitors 27 both converter circuits 18th electrically connected.

The electrodes 40a , 40b form DC signal paths between the DC connection points 22a , 22b and the converter circuits 18th the end. By having the DC connection points 22a , 22b and the converter circuits 18th are arranged symmetrically, the DC signal paths are between the DC connection points 22a , 22b and the converter circuits 18th of equal length. The DC signal can therefore be used by both converter circuits 18th are provided essentially at the same time and without any offset. As the converter circuits 18th and the AC connection panels 28 are symmetrical and structurally identical to one another, there are also AC signal paths between the respective converter circuit 18th and the phase connection set of the electric drive machine connected to it 2 of equal length. In this way, the alternating signals can also be fed to the two sets of phase connections at the same time and without any offset.

In 6th it is shown that the electrode stack 39 with an EMC protective layer 41 is covered. The EMC protective layer 41 has through openings 42 on to the converter circuits 18th who have favourited AC connection panels 28 and the DC connection points 22a , 22b to be able to contact, for example, for control and / or diagnosis. The inverter electronics 12th also, as in 7th shown a circuit board 43 with a control device 44 on. The control device 44 has, for example, a driver and control circuit for controlling the converter circuits 18th and an evaluation device for evaluating measurement signals from diagnostic sensors. The board 43 with the control device 44 is like in 8th shown by a protective cover 45 covered. The inverter electronics 12th is then covered by the cover 11 covered by the cover 11 on the carrier 10 is attached. The inverter 3 thus has a layer stack of carrier 10 , Circuit carriers 37 with converter circuits 18th , Electrode stack 39 , EMC protective layer 41 , Circuit board 43 , Protective cover 45 and cover 11 on.

Claims (14)

At least six-phase inverter (3) for an electric drive unit (1) of a motor vehicle, comprising: - An inverter electronics (12) with - At least two converter circuits (18) for converting a direct signal into alternating signals for phase connections of an electric drive machine (2) of the drive unit, - A DC connection field (19) with DC connection points (22a, 22b) electrically connected on the input side to the converter circuits (18) for supplying the DC signal and - At least two AC connection fields (28), which are electrically connected on the output side to the converter circuits (18), each with three AC plug contacts (31a, 31b, 31c) via which the alternating signals can be fed to the phase connections, - A carrier (10) for the inverter electronics (12), the converter circuits (18) being arranged between the at least two AC connection fields (28) so that AC signal paths between the converter circuits (18) and the respective AC plug contacts (31a , 31b, 31c) are essentially the same length, the DC connection points (22a, 22b) being positioned in relation to the converter circuits (18) in such a way that DC signal paths between the DC connection points (22a, 22b) and the respective converter circuit ( 18) are essentially the same length, and wherein the AC plug contacts (31a, 31b, 31c) are passed through the carrier (10), and - A cover (11) which is connected to the carrier (10) to form a housing end part (7) for accommodating the inverter electronics (12), the housing end part (7) having a central housing (5) for accommodating the electric drive machine (2 ) is connectable and wherein when the housing end part (7) is assembled with the central housing (5), the AC plug contacts (30a, 30b, 30c) can be plugged together with the phase connections. Inverter (3) Claim 1 , characterized in that the DC connection panel (19) has DC contact elements (20a, 20b) which are passed through the carrier (10) and, when the housing end part (7) is assembled with the central housing (5), are integrated with a central housing external to the inverter DC filters (17) can be connected. Inverter (3) Claim 2 , characterized in that the DC connection panel (19) has DC current conductors (21a, 21b) which are connected at one end to the DC contact elements (20a, 20b) and at their other end the DC connection points (22a, 22b) train. Inverter (3) according to one of the preceding claims, characterized in that the DC connection field (19) has an electrode stack (39) with a plate-shaped first electrode (40a) and a plate-shaped second electrode (40b), the electrode stack (39) the converter circuits (18) is arranged to cover and each electrode (40a, 40b) of the electrode stack (39) is electrically connected to one of the DC connection points (22a, 22b) and to the converter circuits (18). Inverter (3) Claim 4 , characterized in that the electrode stack (39) is covered by an EMC protective layer (41). Inverter (3) Claim 4 or 5 , characterized in that the inverter (3) has a circuit board (44) with a control device (45) for controlling the converter circuits (12), the circuit board (44) being arranged so as to overlap with the electrode stack (39). Inverter (3) according to one of the preceding claims, characterized in that each converter circuit (18) has a switching unit (23) having at least three half bridges (25) with semiconductor switches (26) and one electrically connected to the DC connection points (22a, 22b) Intermediate circuit unit (24), the switching units (23) being arranged between the AC connection panels (28) and the intermediate circuit units (24) and the DC connection points (22a, 22b) being arranged between the switching units (23). Inverter (3) Claim 7 , characterized in that the inverter (3) has a circuit carrier (37) on which the converter circuits (18) are arranged, with a respective AC power terminal (30a, 30b, 30c) of the half bridges (25) overlapping with a respective AC - Busbar (29a, 29b, 29c) of the AC connection panel (28) is arranged and is electrically and mechanically connected to the AC busbar (29a, 29b, 29c) by means of laser welding and / or resistance welding. Inverter (3) according to one of the preceding claims, characterized in that the inverter (3) additionally has an angular position encoder for measuring a position of a rotor of the electric drive machine, the angular position encoder being at least partially passed through the carrier (10) and when the Housing end part (7) with the central housing (5) can be positioned on a rotor shaft of the drive machine (2) connected to the rotor, and measurement signals from the angular position encoder can be fed to a control device (44) of the inverter (3) via a communication link. Inverter (3) according to one of the preceding claims, characterized in that the housing end part (7) has cooling ribs (13) for passive cooling and / or cooling channels (14) through which a cooling fluid can flow for active cooling of the inverter electronics (12). Electric drive unit (1) for a motor vehicle with - an electric drive machine (2), - A central housing (5) in which the electric drive machine (2) is arranged, and - An inverter (3) according to one of the preceding claims, wherein the central housing (5) and the housing end part (7) of the inverter (3) are joined together axially along an axis of rotation (R) of the electric drive machine (2) and phase connections of the drive machine ( 2) are plugged together with the AC plug contacts (30a, 30b, 30c). Electric drive unit (1) according to Claim 11 , characterized in that the electric drive unit (1) additionally has a gear (4) which is arranged in a further housing end part (6), the housing end part (7) of the inverter (3), the central housing (5) and the other Housing end part (6) for the transmission (4) are axially assembled to form an overall housing (8) of the electric drive unit (1) and the central housing (5) is arranged between the two housing end parts (6, 7). Electric drive unit (1) according to Claim 11 or 12th , characterized in that the central housing (5) has a shaft (46) which extends axially along the axis of rotation (R) and in which a DC filter (17) is arranged, the DC filter (17) in the assembled state of the Central housing (5) is electrically connected to the housing end part (7) of the inverter (3) with the DC connection panel of the inverter (3). Motor vehicle with an electric drive unit (1) according to one of the Claims 11 until 13th , wherein the axis of rotation (R) of the drive machine (2) of the drive unit (1) is oriented parallel to a transverse direction of the vehicle.

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