converter

Abstract

The invention relates to a converter comprising a housing, which has an integrated cooling channel, and comprising a housing cover, wherein: the housing has a housing base and housing walls; a plurality of attachment planes are provided parallel to the housing base, and a plurality of connection planes are provided on a housing wall so as to be perpendicular to said attachment planes; a capacitor, at least one IGBT and at least one AC busbar are arranged in the housing, and the housing wall has through-openings; and connection plugs project through the through-openings into the housing and are attached to the connection planes. According to the invention, the attachment planes are mutually spaced such that contact surfaces of connection bars of the capacitor and of the AC busbars are in a plane that corresponds to a contact plane of the IGBTs, and the AC busbars are fixed, at a fixing point, relative to the housing such that the introduction of force into the power connections of the IGBT modules is reduced.

Description

[0001] Inverter

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

[0003] Inverters, or power converters, are electronic devices used to convert electrical energy from one form to another. Inverters are also used in the powertrain of an electric vehicle and are used to change the voltage, frequency, and type of current.

[0004] The design of a power converter can vary depending on the application. In motor mode, the power converter converts the direct current, for example, from a battery, into an alternating current. In generator mode, i.e., during recuperation, the power converter converts the alternating current from the electric motor back into a direct current suitable for charging the connected battery.

[0005] Modern power converters often use semiconductor devices such as IGBTs to convert energy. These devices are controlled by a circuit, often implemented on a microcontroller-based control board.

[0006] Cooling is an important aspect in the design of converters or power inverters, as losses occur in the form of heat and must be dissipated. Effective cooling is required to keep the operating temperature within safe limits and to achieve the specified performance and expected service life.

[0007] Automotive converters typically use water cooling to dissipate heat. The general structure of converters is well known from the StdT (standard technical school). The converter generally has a metal housing with a hermetically sealed lower and upper section, which houses one or more required electronic components, such as one or more power semiconductors.

[0008] Such a converter or inverter system is known from DE 10 2020 121 917 A1. A multi-part housing is proposed, 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. A disadvantage of such a design is the increased assembly effort, particularly the need for assembly from two sides.

[0009] Another power converter is known, for example, from DE10 2017 127 383 A1.

[0010] The object of the invention is to propose an inverter whose functional reliability is improved and the assembly effort is reduced.

[0011] 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.

[0012] A converter is proposed which comprises a housing with an integrated cooling channel and a housing cover, wherein the housing has a housing base and housing walls, and wherein a plurality of fastening levels are provided parallel to the housing base and a plurality of connection levels are provided perpendicular to these on a housing wall, wherein a capacitor, at least one IGBT and at least one AC busbar are arranged in the housing and the housing wall has openings, wherein connection plugs protrude through the openings into the housing and are fastened to the connection levels.

[0013] According to the invention, it is proposed that the fastening planes are spaced apart from one another in such a way that contact surfaces of connecting rails of the capacitor and the AC busbars lie in a plane that corresponds to a contact plane of the IGBTs, and the AC busbars are fixed at a fixing point relative to the housing in such a way that the force input to the IGBT modules from the AC busbars is reduced.

[0014] The fixing point can be designed as a mounting surface to which the AC busbars are screwed. The purpose of the fixing is to keep the force acting on the IGBT module connections within the permissible range, i.e., to reduce it. Forces can arise, among other things, due to different thermal expansion coefficients or thermal expansion of the installed materials and components, as well as shock and vibration of massive components (e.g., current transformers).

[0015] The fixing point is the position at which the AC busbar is fixed relative to the housing. The fixing point can be designed as a mounting surface to which the AC busbar is screwed, so that no excessive forces from the AC busbar can act on the corresponding IGBT module. Furthermore, heat can be dissipated via the mounting surface, so that different temperature levels can arise on either side of the fixing point. Furthermore, it is advantageous to keep the clamping length of the AC busbar between the IGBT module and the fixing point as short as possible.

[0016] Furthermore, it is proposed that each AC busbar be coupled to a contact surface on an AC connector or motor bushing, wherein these are located in the contact plane, and each AC busbar is made of a flat, planar material. Furthermore, in a preferred embodiment, DC busbars are fixed between a DC connector and the capacitor, wherein the DC busbars are made of a substantially planar, planar material. Within the meaning of the invention, an end region of the DC busbar can also be angled to create an alternative contact area.

[0017] Furthermore, a toroidal band core (=filter core) can be arranged around the DC busbars and the DC busbars can be electrically connected to an EMC filter board, or RF capacitors or filter capacitor.

[0018] In a preferred embodiment, a further fastening level can be provided in the housing above the AC busbars, to which a console carrying a control board is fixed.

[0019] Furthermore, each AC busbar can be assigned a current transformer, whereby the current transformers are attached to the AC busbar and the measurement is carried out via Hall plates (magnetic field).

[0020] Preferably, the control board comprises connection plugs that extend through the openings with the housing wall and are attached to the connection levels around the openings.

[0021] Furthermore, a drive unit with an electric motor comprising a described converter is proposed, wherein the coupling of the converter to the electric motor is effected via a support part to which the converter is attached via the connection level.

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

[0023] Fig. 1 : View into the opened converter

[0024] Fig. 2: Section through the converter. For better illustration, many practical details are explained together in the following description. Furthermore, in the interest of simplifying the drawings, some common structures and elements are shown schematically in simplified form, and all cross-sectional areas have been omitted from hatching. Essentially, the graphic representation has been designed to ensure that the details of the invention are clearly visible.

[0025] Figure 1 shows a highly simplified view of the opened converter 1 and Figure 2 shows a section through the converter 1 so that the arrangement of the essential elements of the converter 1 can be seen.

[0026] The housing 2 is trough-shaped and thus comprises a housing base 5 and four housing walls 6. A cooling channel 3 (Fig. 2) is integrated into the housing base 5, which can be connected to a cooling water circuit. The three IGBTs 10a, 10b, 10c are screwed to the housing base 5 at the mounting level 7b above the cooling water channel 3. The cooling water channel 3 is closed off towards the interior of the housing 2 by the IGBTs 10a, b, c, so that the cooling fin structure of the IGBTs 10a, 10b, 10c is immersed in the cooling water or is surrounded by cooling water.

[0027] The capacitor is mounted on the mounting plane 7a of the housing 2. The AC connector 15, to which the electric motor is connected, is mounted on the connection plane 8a of a housing wall 6, with the connector 3 comprising contacts that protrude through the opening 12a into the housing interior.

[0028] According to the invention, a contact level 13 is provided in which the contacting between the components capacitor 9, IGBTs 10 a, b, c, AC busbars 11 a, b, c and the contacts of the AC connector 15 takes place. This means that all electrical contact surfaces meet in the contact level 13. During assembly, the IGBTs 10 a, b, c are first screwed onto the mounting level 7b. The capacitor 9 can then be mounted on level 7a, and the connecting rails 14 a, b, c can be connected to the contact surfaces of the IGBTs 10 a, 10 b, 10 c.

[0029] Be connected. After installing the AC connector 15, the AC busbars 11a, b, c, which consist of a flat material, can be mounted on the contact surfaces of IGBTs 10a, 10b, 10c and the contact surfaces of the AC connector 15. To reduce the force applied to the connection surfaces of the IGBT modules, the AC busbars 11a, b, c are fixed at the fixing point 18 opposite the housing 2. This fixing point also lies in the contact plane 13. An intermediate piece can be provided between the housing and the AC busbars 11a, b, c, as shown here.

[0030] To secure the control board 23, a further mounting level 7d is provided in the housing, to which a bracket 22 is attached, with the control board 23 in turn being fixed to the bracket 22. The board 23 is further secured via the connector plugs 17, which protrude outward through openings 12c in the housing wall 6 and are screwed to the housing at the connection level 8c.

[0031] The DC connector 16 is also fixed to the housing wall 6. The fixing planes 8a, b, c are all arranged parallel to each other, although they may also be located in the same plane.

[0032] The DC busbars 19a, b are arranged between the DC connector 16 and the capacitor 9 and are connected to each other via electrical contact surfaces (not shown in detail). All electrical connections can be made using a screw connection.

[0033] The DC busbars 19a, b are also made of a substantially flat material, with the DC busbars 19a, b being angled in the illustration for contact with the capacitor 9. An input filter consisting of one or more toroidal cores, filter capacitors, and RF resistors is provided at the DC input of the inverter. The toroidal core 20 is arranged around the DC busbars 19, and the DC busbars 19a, b are electrically connected to an EMC filter board 21 (filter capacitors and RF resistors).

[0034] A current transformer 24a, b, c is provided on each of the AC busbars 11a, b, c. The converter can be a component of a drive unit with an electric motor (not shown here). A support member can be provided to couple the electric motor and converter 1, whereby converter 1 can be coupled to the support member at the connection level 8d.

[0035] List of reference symbols

[0036] 1 night

[0037] 2 housings

[0038] 3 cooling channel

[0039] 4 housing covers

[0040] 5 Case back

[0041] 6 housing walls

[0042] 7a, b, c, d mounting level

[0043] 8a, b, c, d Connection level 9 Capacitor

[0044] 10a, b, c IGBT 11a, b, c AC busbar 12a, b, c Breakouts

[0045] 13 Contact level

[0046] 14a, b, c connecting rail

[0047] 15 AC connectors

[0048] 16 DC connectors

[0049] 17 connectors

[0050] 18 Fixation point

[0051] 19a, b DC busbars

[0052] 20 toroidal core / filter core

[0053] 21 EMC filter board

[0054] 22 Console

[0055] 23 Control board

[0056] 24a, b, c current transformer

[0057] 25 DC connection of the capacitor

Claims

Patent claims 1 . A converter (1) comprising a housing (2) with an integrated cooling channel (3) and a housing cover (4), wherein the housing (2) has a housing base (5) and housing walls (6), and wherein a plurality of fastening planes (7a, 7b, 7c, 7d) are provided parallel to the housing base (5) and a plurality of connection planes (8a, 8b, 8c) are provided perpendicular to these on a housing wall (6), wherein a capacitor (9), at least one IGBT (10a, b, c) and at least one AC busbar (11a, b, c) are arranged in the housing and the housing wall (6) has openings (12a, b, c), wherein connection plugs (15, 16, 17) protrude through the openings (12a, b, c) into the housing and are fastened to the connection planes (8a, 8b), characterized in that the fastening planes (7a, 7b, 7c) are spaced from one another in such a way that that contact surfaces of connecting rails (14a, b, c) of the capacitor (9) and the AC busbars (11 a, b, c) lie in a plane which corresponds to a contact plane (13) of the IGBTs (10a, b,c), and the AC busbars (11a, b, c) are fixed at a fixing point (18) relative to the housing in such a way that the force input to the IGBT modules from the AC busbars (11a, b, c) is reduced.

2. Converter according to claim 1, characterized in that each AC busbar (11a, b, c) is coupled to a contact surface on an AC connection plug (15), these lying in the contact plane (13) and each AC busbar (14a, b, c) consists of a flat material.

3. Converter according to claim 1, characterized in that between a DC connection plug (16) and the capacitor (9) DC- Busbars (19a, b) are fixed, wherein the DC busbars (19a, b) consist of a substantially flat material.

4. Converter according to claim 1, characterized in that one or more toroidal band cores (20) are arranged around the DC busbars (19a, b) and the DC busbars (19a, b) are electrically conductively connected to an EMC filter board (21).

5. Converter according to claim 1, characterized in that in the housing (2) a further fastening level (7d) is provided above the AC busbars 11a, b, c, to which a bracket (22) carrying a control board (23) is fixed.

6. Converter according to claim 1, characterized in that each AC busbar (11a, b, c) is assigned a current transformer (24a, b, c), wherein the current transformer (24a, b, c) is fastened to the AC busbar (11a, b, c).

7. Converter according to claim 1, characterized in that the control board (23) comprises connection plugs (17) which extend through the openings (12c) with the housing wall (6) and are fastened to the connection plane (8c).

8. Drive unit with an electric motor comprising a converter according to one of claims 1 to 7, characterized in that the coupling of the converter (1) to the electric motor takes place via a support part to which the converter (1) is fastened via the connection plane (8d).

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