US-12621968-B2 - Power electronic arrangement for an electric machine and motor vehicle

US12621968B2US 12621968 B2US12621968 B2US 12621968B2US-12621968-B2

Abstract

A power electronic arrangement for an electric machine, includes an inverter, power electronic components accommodated in at least one power module, an intermediate circuit connected to the inverter across connection contacts of the at least one power module and having at least one intermediate circuit energy accumulator, and a heat sink to which the at least one power module is thermally connected for cooling, the connection contacts are arranged at a margin and flat against a substrate carrying one or more power semiconductors, and are thermally coupled to the heat sink via the substrate, wherein the at least one intermediate circuit energy accumulator is connected electrically and thermally to the connection contacts to cool the at least one intermediate circuit energy accumulator.

Inventors

Daniel Ruppert

Assignees

AUDI AG

Dates

Publication Date: 20260505
Application Date: 20231213
Priority Date: 20221214

Claims (11)

1 . A power electronic arrangement for an electric machine, comprising: an inverter; a plurality of power electronic components accommodated in at least one power module; an intermediate circuit connected to the inverter across connection contacts of the at least one power module and having at least one intermediate circuit energy accumulator, and a heat sink to which the at least one power module is thermally connected for cooling, wherein the heat sink includes a cavity that, in operation, receives a flow of a cooling fluid, and includes a cooling structure located in the cavity, wherein the connection contacts are arranged at a margin and flat against a substrate carrying one or more power semiconductors, and are arranged in a region adjacent to the cooling structure located in the cavity of the heat sink which is associated with the at least one power module such that the connection contacts of the at least one power module are thermally coupled to the heat sink via the substrate, and wherein the at least one intermediate circuit energy accumulator is connected electrically and thermally to the connection contacts to cool the at least one intermediate circuit energy accumulator.
2 . The power electronic arrangement according to claim 1 , wherein the at least one intermediate circuit energy accumulator is at least one intermediate circuit capacitor.
3 . The power electronic arrangement according to claim 1 , wherein the connection contacts include a metallization layer of the substrate, or the substrate is a Direct Bond Copper (DBC) substrate.
4 . The power electronic arrangement according to claim 1 , wherein the connection contacts includes a connection layer applied to the substrate.
5 . The power electronic arrangement according to claim 4 , wherein the connection layer is a copper layer applied to a metallization layer of the substrate.
6 . The power electronic arrangement according to claim 1 , wherein the intermediate circuit is connected by flat connecting tabs to the connection contacts.
7 . The power electronic arrangement according to claim 6 , wherein the flat connecting tabs are made of copper.
8 . The power electronic arrangement according to claim 6 , wherein the flat connecting tabs are welded onto the connection contacts.
9 . The power electronic arrangement according to claim 6 , wherein the at least one intermediate circuit energy accumulator is received in a housing from which the connecting tabs stick out.
10 . The power electronic arrangement according to claim 1 , wherein the at least one power module is thermally attached and fastened to the heat sink by soldering or sintering.
11 . A motor vehicle, comprising: an electric machine that operates as a traction machine; and a power electronic arrangement associated with the electric machine, wherein the power electronic arrangement includes: an inverter; a plurality of power electronic components accommodated in at least one power module; an intermediate circuit connected to the inverter across connection contacts of the at least one power module and having at least one intermediate circuit energy accumulator, and a heat sink to which the at least one power module is thermally connected for cooling, wherein the heat sink includes a cavity that, in operation, receives a flow of a cooling fluid, and includes a cooling structure located in the cavity, wherein the connection contacts are arranged at a margin and flat against a substrate carrying one or more power semiconductors, and are arranged in a region adjacent to the cooling structure located in the cavity of the heat sink which is associated with the at least one power module such that the connection contacts of the at least one power module are thermally coupled to the heat sink via the substrate, and wherein the at least one intermediate circuit energy accumulator is connected electrically and thermally to the connection contacts to cool the at least one intermediate circuit energy accumulator.

Description

BACKGROUND Technical Field The disclosure relates to a power electronic arrangement for an electric machine, comprising an inverter, the power electronic components of which are accommodated in at least one power module, an intermediate circuit connected to the inverter across connection contacts of the at least one power module and having at least one intermediate circuit energy accumulator, especially an intermediate circuit capacitor, and a heat sink, to which the at least one power module is thermally connected for cooling. In addition, the disclosure relates to a motor vehicle. Description of the Related Art Electric machines, such as synchronous machines or asynchronous machines, are used as traction machines in motor vehicles, such as electric motor vehicles and hybrid motor vehicles. For the operation of the electric machine from a DC voltage network, which can be powered for example from a high-voltage battery of the motor vehicle, a power electronic arrangement associated with the electric machine comprises an inverter, which can also be called a traction inverter or a drive inverter. The electric machine is usually connected to the DC voltage network across an intermediate circuit having at least one intermediate circuit energy accumulator, usually at least one intermediate circuit capacitor. The inverter, which is usually realized through a bridge circuit, comprises power semiconductor components, especially semiconductor switches and diodes, which need to be cooled. For this, a cooling device is usually provided, having a heat sink to which the power semiconductor components are thermally connected for the cooling. For example, it can be provided for this that the power semiconductor components are provided in so-called power modules, such as molded half-bridge modules. One such power module can be provided for each phase of the electric machine. The power modules comprise, in addition to control leads, connection contacts at the machine side for connection to corresponding stator windings and connection contacts at the DC voltage side for connection to the intermediate circuit, especially the intermediate circuit energy accumulator. It is known in the prior art how to realize the connection contacts by connecting tabs sticking out from the power module, to which corresponding connecting tabs of the intermediate circuit energy accumulator, especially the intermediate circuit capacitor, can be welded. Besides the desired current flow, a heat flow also occurs through the interface with the intermediate circuit energy accumulator, since the intermediate circuit capacitor is usually not connected to the cooling device. Thus, the power electronic arrangements known in the prior art have the drawback that the cooling or the cooling fluid flow is only confined to the semiconductor components of the power modules. The intermediate circuit energy accumulator is not connected to this cooling, especially this active cooling. This results in larger design of the intermediate circuit capacitor, which brings with it higher production costs, larger design volume, and heavier weight. Because of premature derating, there may be a decrease in the maximum output power. The service life, especially that of the intermediate circuit energy accumulator, may be reduced by thermal stress. In this context, it would also be conceivable to attach the intermediate circuit energy accumulator itself to the active cooling or an active cooling. However, this would lead to higher production costs for the power electronic arrangement and a more costly cooling device would be needed. The design volume and the weight of the power electronic arrangement would be increased. JP 2017188998 A discloses a power converting device in which a current busbar is actively cooled in order to make possible a high-frequency drive with cooling of a high-temperature switch element, wherein a high temperature of a capacitor element is prevented. It is proposed here, specifically, to fasten the switch element and the capacitor each directly to a heat sink and in addition to also attach a connection site of busbars of the switch element and the capacitor to a surface of the heat sink across an electrically insulating, heat conducting material. A screw connection is proposed for this. In other words, not only are both a capacitor element and a switch element attached to the heat sink here, but also the busbars are attached to an intermediate point. This produces a complex and costly layout of the cooling device. DE 10 2014 106 395 A1 discloses an integrated electric and thermal solution for a capacitor housing of an inverter of the intermediate circuit. Here, capacitor elements in a housing are electrically connected to a busbar, while the busbar is situated in proximity to an insulation layer and is configured to extend beneath the capacitor elements along the housing side and the housing length, in order to provide a broader pathway for the heat dis