Designing Thermally Uniform Heatsink with Rectangular Pins for High-Power Automotive SiC Inverters

Paper in proceedings, 2020

This paper presents the design of a high-performance liquid-cooled heatsink for three-phase automotive inverters that attains uniform thermal distribution at the surface of the three power modules. Power modules with SiC-MOSFETs are used in this study and a uniform thermal distribution on the heatsink guarantees equal thermal loading of the semiconductor devices. A comparative study of various cooling plate geometries is made and their effectiveness in meeting the design objectives of low sink-temperature and coolant pressure drop and the highest possible temperature uniformity along the surface of the plate is presented. Plates with straight and wavy fins are compared with designs accommodating rectangular pins and the advantages of each case is shown with the corresponding simulation results. Key design parameters of the cooling plate geometries are optimized with an iterative process, which is presented with selective simulation results of 3D Conjugate Heat Transfer computations for coolant flow rates up to 10~l/min. The final heatsink design accommodates multiple rectangular pins and attains temperature difference of less than 2oC among the three SiC power modules.