Multidisciplinary cooling design tool for electric vehicle SiC inverters utilizing transient 3D-CFD computations

Abstract

This paper proposes a new design tool that can be used for the development of a proper cooling component for high-power three-phase SiC module-packs for electric vehicles. Specifically, a multidisciplinary approach of the design process is presented that is based on the accurate electrical, thermal and fluid-mechanics modeling as well as computational testing of a high-power three-phase SiC module-pack under transient-load conditions, so that it can effectively meet the highly-demanding cooling requirements of an electric vehicle inverter. The cooling plate is initially designed by using steady-state based 3D-computational-fluid-dynamic (CFD) tool, as in a conventional method. Then, the proposed design algorithm fine-tunes it through transient 3D-CFD computations by following a specific iterative improvement procedure considering the heat dissipation requirements for the SiC power switches during the official driving cycles for passenger vehicles and during abrupt acceleration tests under several ambient environments. Therefore, not only overheating at all operating conditions is avoided, but also, accurate thermal modeling of the individual inverter modules is provided that can be used for lifetime estimations and for calculating the overload capability of the inverter. The design improvement attained with the proposed procedure against the conventional steady-state approach is validated on a traction 450 A SiC inverter with the model of a real passenger vehicle.