Converter for supplying power to an electric motor, and drive unit

Abstract

The invention relates to a converter (1) for supplying power to an electric motor, said converter comprising a housing (2) with a trough-like lower part (3), into which a cooling channel system (4) for connection to an external coolant circuit is integrated. The converter (1) furthermore comprises a cover placed on the lower part (3), at least one IGBT module (6a, 6b, 6c) arranged in the interior of the housing (2) and fixed to the lower part (3), and a power connection (7) via which at least three IGBT modules (6a, b, c) arranged on the lower part can be connected to an electric motor. According to the invention, the power connection (7) comprises a flange part (14) and at least three busbars (15a, b, c) and the lower part (3) has a connection side (9) with a connection plane (10) and a sealing plane (11a) arranged parallel thereto, wherein in the connection plane (10), means for fastening (12) the converter (1) to a carrier part (13) are provided and wherein in the sealing plane (11a), a feedthrough (16a) is provided through which the busbars (15a, b, c) extend and are connected in an electrically conductive manner to the IGBT modules (6a, b, c) of the converter (1).

Description

[0001] Inverter for powering an electric motor and drive unit

[0002] The invention relates to a converter for supplying power to an electric motor and a drive unit with a corresponding converter.

[0003] Such a converter, also known as a power converter or inverter, provides the voltage required to operate an electric motor, for example, in a motor vehicle's drive system. The converter has a metal housing with a lower and an upper section, which can usually be hermetically sealed and in which one or more required converter electronic components, such as one or more power modules, also known as IGBTs, are housed.

[0004] To cool the IGBT modules, a cooling device is provided on the housing side, which essentially cools the IGBT modules of the converter, which can be integrated into a cooling medium circuit so that heat loss generated during operation can be dissipated via the coolant.

[0005] Such a converter or inverter system is known from DE 10 2020 121 917 A1. This discloses a multi-part housing comprising an electronics level, a power level, and a connection level. The interior of the housing has several zones in which different conditions prevail with regard to temperature and / or EMC shielding. A cooling device is provided for temperature control, which can be connected to a cooling circuit.

[0006] A motor unit with an inverter is known from WO 19208069 A1. The proposed motor unit comprises a motor with a motor housing and an inverter with an inverter housing. It is proposed to provide a motor unit in which the inverter housing and the motor housing are fixed to one another, the connection being made by means of bolts. The electrical connection between the inverter unit and the motor is established via a motor connection terminal with three busbars. The busbars, or inverter output busbars, protrude from the inverter housing so that they can be inserted into an opening in the motor housing. The busbars, which are supported by the motor connection terminal, can be electrically connected to the motor within the motor housing.

[0007] A motor connection terminal is also known from WO 19208445 A1. The motor connection terminal comprises a plug-in connection consisting of two connectors, with the busbars being routed through one connector. The busbars are designed to extend through the openings in the motor housing and the converter housing into the respective housings, allowing the busbar to be electrically connected to the motor and converter there by means of a screw connection. The plug-in connection is also designed to align the motor housing and converter housing with each other.

[0008] This design requires that the wiring elements and busbar be able to accommodate elastic deformation. To mount the inverter to the motor, the motor housing must have an opening with a cover through which the screw connection can be made.

[0009] The object of the invention is to propose a converter that provides an improved solution for the connection to the motor.

[0010] The object is achieved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention can be found in the subclaims.

[0011] A converter for supplying power to an electric motor is proposed, which comprises a housing with a trough-like lower part into which a cooling channel system for connection to an external coolant circuit is integrated.

[0012] Furthermore, the converter comprises a cover placed on the lower part, at least one IGBT module arranged inside the housing and fixed to the lower part, and a power connection via which at least three IGBT modules arranged on the lower part can be connected to an electric motor.

[0013] According to the invention, the power connection comprises a flange part and at least three busbars, and the lower part has a connection side with a connection plane and a sealing plane arranged parallel thereto. Means for attaching the converter to a support part are provided in the connection plane, and a bushing is provided in the sealing plane through which the busbars extend and are electrically connected to the IGBT modules of the converter. The support part functions as a terminal box for connecting the electric motor.

[0014] Furthermore, it is proposed that the cooling channel system is composed of several cooling channel sections integrated into the lower part, wherein at least three open cooling channel sections are provided, wherein the opening of the cooling channel sections is designed such that the openings can be closed by means of the IGBT modules.

[0015] In a preferred embodiment, it is proposed that the flange part of the power connector comprises at least three receptacles in which the busbars can be permanently or detachably secured. The busbars are thus inserted into the receptacles, and means are provided in the receptacles by means of which the busbars can be locked. The means can be a casting compound or an adhesive, or a locking device, e.g., a tongue and groove, can be provided. The casting compound can be a plastic casting into which the busbar is cast.

[0016] Furthermore, the flange part can comprise a seal and an insulating collar, whereby the seal is arranged between the sealing plane on the housing and the flange part when the flange part is installed. The converter is therefore a hermetically sealed unit, so that the converter can be replaced. Furthermore, a power connection is also possible in which the busbars comprise a plug-in solution. In all solutions, only the power connection is adapted, whereby the connections within the converter and the connection from the flange part to the lower part, with the seal arranged in between, remain identical, so that the inverter housing and internal components do not have to be adapted. The converter can be pre-assembled and tested for leaks and function without the converter on the drive train having to be opened again.

[0017] In a preferred embodiment, the busbar has a connection surface, wherein the insulating collar radially encloses the connection surface in sections.

[0018] Furthermore, a drive unit with an electric motor is proposed, which comprises a converter, wherein a support part is provided between the electric motor and the converter and the converter is fastened to the support part in the connection plane and is carried by it.

[0019] The support part can enclose a connection space that can be closed with a support part cover, whereby the flange part protrudes into the connection space so that the connecting cables of the electric motor can be connected to the busbars.

[0020] Particular advantages of the proposed design are that the converter or inverter and the motor are separately sealed from the environment, thus ensuring that the interior spaces of the converter and motor are separated or independent from each other.

[0021] The circumferential contact, which is formed via the carrier part between the inverter and the electric motor, also improves the EVM safety of the system consisting of the inverter and the electric motor.

[0022] The invention is explained below with reference to the figures. The figures show in detail:

[0023] Fig. 1 : Connection side of the converter

[0024] Fig. 2: Cooling channel system with mounted IGBT in section

[0025] Fig. 3: Power connection installed

[0026] Fig. 4: Power connection between IGBT and electric motor Figure 1 shows a section of the connection side 9 of the converter 1 with the DC connection 22 for supplying power to an electric motor 8 and the connections 23 for controlling the converter 1.

[0027] This illustration essentially shows the support part 13, via which the converter 1 is attached to the housing of the electric motor 8. The support part 13 is shown in this view without the support part cover 24, so that the connection compartment 26 of the support part 13 can be seen, in which the three connection cables 25 run between the power connection 7 and the electric motor 8.

[0028] The lower part 3 is designed like a trough, and all components for the power supply between the DC connection 22 and the power connection 7, as well as the control board (not shown here), are located inside. The lower part 3 of the converter 1 is also closed with a cover (not shown).

[0029] Figure 2 shows a section through the lower part 3 with the cooling channel system 4 for connection to an external coolant circuit. The cooling channel system 4 is integrated into the lower part 3 of the housing 2. For example, the lower part 3 can be a cast part into which the cooling channel system is cast. Alternatively, a separate cooling system can also be implemented, which is designed as a separate component and inserted into the lower part.

[0030] The cooling channel system 4 is composed of several cooling channel sections 5a, b, c integrated into the lower part, with at least three parallel, open cooling channel sections 5c being provided, which are designed such that the openings can be closed by the IGBT modules 6a, 6b, 6c. The IGBT modules 6a, 6b, 6c are thus mounted on the cooling system and form a wall of the cooling channel section 5c, so that the IGBT modules 6a, 6b, 6c come into direct contact with the cooling water.

[0031] As can be seen from Figure 2, the cooling channel system comprises two parallel channels 5a, each of which is connected to the cooling channel section 5c via connecting channel sections 5b. The cooling water can thus flow from the left channel 5a via the left connecting channel section 5b, the cooling channel section 5c, and the right connecting channel section 5b into the right channel 5a. Not shown is that three such parallel cooling water streams are provided in the cooling water system, so that each IGBT module 6a, 6b, 6c is assigned a separate cooling water stream.

[0032] Fig. 3 shows a power connector 7, which consists of a flange part 14 and at least three busbars 15a, b, c. The power connector 7 is attached to the lower part 3. The attachment is made to a sealing plane 11 on the lower part 3, with a seal 21a provided between the flange part 14 and the sealing surface of the sealing plane 11a. The attachment can be made, for example, by means of a screw connection.

[0033] Parallel to the sealing plane 11a, the lower part 3 has a connection plane 10, wherein the connection plane 10 provides means 12 for fastening the converter 1 to the support part 13, in this case a screw connection. Due to the parallel offset of the sealing plane 11a and the connection plane 10, the flange of the flange part 14 can be arranged between the lower part 3 and the support part 13, wherein seals 21a, b are provided between the contact surfaces or sealing planes 11a, b.

[0034] The busbars 15a, b, c are guided through receptacles 18a, b, c in the flange portion 14 of the power connector 7. The receptacles 18a, b, c are designed such that the busbars 15a, b, c are firmly positioned within them. This can be achieved by casting or a form-fitting and sealed connection. To ensure the installed seals 21a, b are correctly pressed into place, the depth of the sealing groove on the outside was reduced by the nominal width of the designed gap.

[0035] In the lower part 3 in the area of ​​the sealing plane 11a and also in the support part 13, a bushing 16a, b is provided through which the busbars 15a, b, c extend and are electrically connected to the IGBT modules 6a, b, c of the converter 1. This design hermetically seals the converter interior from the environment and from the terminal compartment 26.

[0036] This design also allows the use of an alternative busbar in which the inverter is not attached to the electric motor, but a longer cable connection is implemented between the inverter and the electric motor.

[0037] In Fig. 4, the power connection between IGBT module 6 and electric motor 8 is shown again from a different view in section through a busbar 15. The busbar 15 runs through the flange part 14 and there is a screw connection between IGBT module 6 and busbar 15 as well as a screw connection between the connecting cable 25 and the connection surface 19 of the busbar 15.

[0038] The proposed flange part 14 further comprises an insulating collar 20, which advantageously restricts accessibility to the connection point. The insulating collar 20 encloses the connection surface in sections in the radial direction.

[0039] Furthermore, the carrier part 13 is shown, which encloses a connection space (26) which can be closed with a carrier part cover 24, wherein the flange part (14) is

[0040] Feedthrough 16b protrudes into the connection space (26) so that the connecting cable (25) of the electric motor (8) can be easily connected to the busbars (15a, b, c).

[0041] List of reference symbols

[0042] 1 inverter

[0043] 2 housings

[0044] 3 Lower part

[0045] 4 Cooling channel system

[0046] 5a, b, c Cooling channel sections

[0047] 6a, b, c IGBT module

[0048] 7 Power connection

[0049] 8 electric motor

[0050] 9 Connection side

[0051] 10 connection level

[0052] 11 a, b Sealing level

[0053] 12 threads

[0054] 13 Support part

[0055] 14 Flange part

[0056] 15a, b, c Busbars

[0057] 16a, b Implementation

[0058] 17 Top

[0059] 18a, b, c recording

[0060] 19 Connection surface

[0061] 20 insulating collars

[0062] 21 a, b seal

[0063] 22 DC connection

[0064] 23 Control connection

[0065] 24 carrier part covers

[0066] 25 connection cables

[0067] 26 Connection compartment

Claims

Patent claims 1 . Converter (1 ) for supplying power to an electric motor, comprising - a housing (2) with a trough-like lower part (3) into which a cooling channel system (4) for connection to an external coolant circuit is integrated, - a lid placed on the lower part (3), - at least one ITGB unit (6a, b, c) arranged inside the housing (2) and fixed to the lower part (3), - and a power connection (7), via which at least three IGBT modules (6a, b, c) arranged on the lower part (3) can be connected to an electric motor (8), characterized in that the power connection (7) comprises a flange part (14) and at least three busbars (15a, b, c) and the lower part (3) has a connection side (9) with a connection plane (10) and a sealing plane (11a) arranged parallel thereto, wherein the connection plane (10) has means (12) for fastening the converter (1) to a support part (13), and wherein a bushing (16a) is provided in the sealing plane (11a), through which the busbars (15a, b, c) extend and are electrically conductively connected to the IGBT modules (6a, b, c) of the converter (1).

2. Converter (1) according to claim 1, characterized in that the cooling channel system (4) is composed of several cooling channel sections (5a, b, c) integrated into the lower part, wherein at least three open cooling channel sections (5c) are provided, wherein the opening of the cooling channel sections (5c) is designed such that the openings can be closed by means of the IGBT modules.

3. Converter (1) according to claim 1, characterized in that the flange part (14) of the power connection (7) comprises at least three receptacles (18a, b, c) in which the busbars (15a, b, c) can be fixed permanently or detachably.

4. Converter (1) according to claim 1, characterized in that the flange part (14) comprises a seal (21a) and an insulating collar (20), wherein the seal (21a) is arranged between the sealing plane (11a) on the housing (3) and the flange part (14) when the flange part (14) is mounted.

5. Converter (1) according to claim 1, characterized in that the busbar (15a, b, c) has a connection surface (19), wherein the insulating collar (20) radially encloses the connection surface in sections.

6. Drive unit (22) with an electric motor (8) comprising a converter according to claims 1 to 5, characterized in that a carrier part (13) is arranged between the electric motor (8) and the converter (1), the converter (1) being fastened to the carrier part (13) in the connection plane (10) and being carried by the latter.

7. Drive unit (22) according to claim 6, characterized in that the carrier part (13) encloses a connection space (24) which can be closed with a cover, wherein the flange part (14) projects into the connection space (23) so that connection cables (25) of the electric motor (8) can be connected to the busbars (15a, b, c).

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