Presentation Description: This work presents a comparative study of two different designs for a 13 kW motor drive for the E-compressor used in a heating, ventilation and air-conditioning (HVAC) system in Electric Vehicles (EVs) by employing SiC MOSFETs of different packages, namely, top-side cooled (TSC) and bottom-side cooled (BSC). Compared with conventional Si-based designs, the SiC-based design can operate at higher switching frequencies with higher efficiency and cooler temperature, and can achieve higher power density with smaller size of motors and EMI filters. Assembly methods and thermal designs for TSC and BSC surface mount SiC MOSFETs for automated production, are detailed in this work. A digital-controlled motor drive prototype with 1200 V / 75 mΩ SiC MOSFETs switched at 20 kHz was built to drive a Permanent Magnet Synchronous Motor (PMSM), showing a peak efficiency of over 98.5% thanks to the low power loss and superior thermal performance of SiC MOSFETs. Compared with traditional Silicon IGBT-based solution, the proposed design has 60% lower power loss at light load ( < 3 kW) and up to 54C cooler junction temperature at full load, enabling higher compressor efficiency and optimized battery utilization across all loads. The experimental results show that the TSC thermal design has around 20C cooler package temperature than the BSC counterpart thanks to better thermal management.
