US-12620870-B2 - Power electronics arrangement for an externally excited synchronous machine and motor vehicle

US12620870B2US 12620870 B2US12620870 B2US 12620870B2US-12620870-B2

Abstract

A power electronics arrangement for an externally excited synchronous machine, may include an inverter power module for each phase of the synchronous machine to form an inverter, an exciter power module including an exciter circuit as well as a common heat sink, to which the power modules are secured and thermally coupled for cooling. The heat sink may comprise a cavity including cooling structures for each inverter power module, each cooling structure being situated adjacent to a respective inverter power module. The cavity may receive a flow for active cooling of the power modules of a cooling fluid entering through an inflow opening of the heat sink to an outflow opening of the heat sink. A cooling structure may be associated with the exciter power module, the cooling structure being adjacent to the excited power module in the cavity.

Inventors

Daniel Ruppert

Assignees

AUDI AG

Dates

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

Claims (9)

1 . A power electronics arrangement for an externally excited synchronous machine, comprising: an inverter, including a plurality of inverter power modules the plurality of inverter power modules including one inverter power module for each phase of the externally excited synchronous machine; and an exciter power module having an exciter circuit, a common heat sink having a cavity, and an exciter cooling structure, the inverter and exciter power modules being secured and thermally coupled to the heat sink for cooling and the exciter cooling structure positioned adjacent to the exciter power module in the cavity, wherein the cavity includes at least one inverter cooling structure, including one inverter cooling structure for each inverter power module each inverter cooling structure of the at least one inverter cooling structure positioned adjacent a respective inverter power module, wherein the cavity is configured to receive a flow for active cooling of the inverter and exciter power modules of a cooling fluid entering through an inflow opening of the common heat sink to an outflow opening of the common heat sink, wherein the exciter and inverter cooling structures each define cooling pathways separate from other exciter and inverter cooling structures, wherein the cooling pathways of each inverter power module of the plurality of inverter power modules run parallel to one another, and wherein each cooling pathway is configured to underlie and primarily cool only a respective one of the plurality of inverter power modules.
2 . The power electronics arrangement according to claim 1 , wherein the common heat sink is oblong shaped, the at least one inverter power module is arranged at a middle of the oblong shaped common heat sink, and the exciter power module connects to a longitudinal end to an inlet side of the common heat sink, the inlet side being present on a longitudinal end of the heat sink and encompassing the inflow opening.
3 . The power electronics arrangement according to claim 2 , wherein when the at least one inverter power module includes a plurality of inverter power modules, the plurality of inverter power modules and associated cooling structures are arranged in succession in the longitudinal direction.
4 . The power electronics arrangement according to claim 1 , wherein the cooling pathways of the plurality of inverter power modules run parallel from an inflow side to an outflow side.
5 . The power electronics arrangement according to claim 4 , wherein the cooling pathway of the exciter power module runs from the inflow opening to the inflow side.
6 . The power electronics arrangement according to claim 1 , wherein the heat sink is a cooling plate and/or comprises of aluminum.
7 . The power electronics arrangement according to claim 1 , wherein the exciter and inverter cooling structures each encompass at least one substructure for increasing the effectively bathed cooling surface and/or for swirling of the cooling fluid.
8 . The power electronics arrangement according to claim 1 , wherein the at least one inverter power module is attached by soldering and/or sintering and the exciter power module is attached by screw fastening and/or clamping.
9 . A motor vehicle, comprising an externally excited synchronous machine as a traction machine, and a power electronics arrangement according to claim 1 .

Description

BACKGROUND Technical Field Embodiments of the invention relate to a power electronics arrangement for an externally excited synchronous machine, such as those included in a motor vehicle. Description of the Related Art An externally excited synchronous machine (ESM) makes do with no magnetic materials in the rotor, by contrast with a permanently excited synchronous machine (PSM). Instead, a magnetic field is generated by flow through an exciter winding in the rotor. This has the benefit of additional degrees of freedom in the regulating and design of the synchronous machine. In a power electronics arrangement for an externally excited synchronous machine, therefore, not only is an inverter required between a DC voltage and the customary multiphase alternating voltages on the stator windings, but also an exciter circuit for the exciter winding. It is known in the art to provide the exciter circuit in an exciter power module and the inverter by inverter power modules for each phase, especially half-bridge modules. Since the power electronic components, especially semiconductor switches and/or diodes of these power modules, i.e., of the exciter power module and the at least one inverter power module, become heated during operation, a cooling is required. While it was typically considered to cool the exciter power module by convection of air, it has been disclosed, for example in DE 10 2019 128 721 A1, to fasten and attach the exciter power module in addition thermally to a heat sink provided for the at least one inverter power module. In this way, an improved cooling of the exciter circuit and its power electronic components was achieved, so that they could be designed smaller. Since the bulk of the lost power occurs in the three inverter power modules for the stator windings, the heat sink is typically designed such that these inverter power modules are cooled the best way possible. In particular, cooling structures are provided between an inflow opening in a cavity of the heat sink receiving a flow of a cooling fluid and an outflow opening from the heat sink adjacent to the thermal coupling site of the inverter power modules, which define in particular cooling pathways and/or increase the cooling surfaces and/or produce swirling of the cooling fluid, which is typically cooling water. Oblong configurations of the heat sink have been disclosed, in which the inverter power modules are arranged centrally in the longitudinal direction, in particular being arranged directly adjacent for multiple phases. The exciter power module could additionally be provided in the longitudinal direction adjacent to an inlet side, especially next to the inflow opening, or at an outlet side, especially next to the outflow opening. In this case, the exciter power module cannot receive an active flow of cooling fluid around or underneath it, since the cooling fluid is taken without swirling through the inflow opening in the direction of the inverter power modules for the stator. The same is true of the outflow side. Because of this, the exciter power module is not optimally cooled. Thermal simulations have also shown that temperatures may occur in the region where the exciter power module is thermally coupled to the heat sink that are up to 30 K higher than those in the region of the cooling structures for the inverter power modules. Thus, it can be said that there is no optimal cooling link for the exciter power module, so that a larger design in terms of the power semiconductor components may be required for the necessary exciter power. For example, a large design space may be provided for a power semiconductor component realized as a chip, so that its heat can be distributed and taken away by a larger surface. This leads to higher manufacturing costs, higher design volume, and greater weight of the exciter power module. Furthermore, neither design provides optimal efficiency of the exciter power module, since greater losses occur, higher design volume is required due to larger intermediate circuit capacitors, and the weight is increased. The maximum output power may be decreased by premature derating. Furthermore, a decreased service life of the exciter power module may occur due to thermal stress. CN 111 933 600 A discloses a DBC substrate, the underside of which is directly bathed in the flow of a cooling medium. A swirl flow structure is provided inside the cavity immediately adjacent to the DBC substrate. BRIEF SUMMARY Embodiments of the present disclosure provide an improved power electronics arrangement in terms of performance capability, service life, efficiency and manufacturing expense of the exciter power module. Embodiments may include a power electronics arrangement including a cooling structure adjacent to the exciter power module in the cavity. The power modules, i.e., the exciter power module and the at least one inverter power module, may encompass the power electronic components of the respectively provided circui