High Power Density SiC-Based Inverter with a Power Density of 70kW/liter or 50kW/kg

Abstract

This paper presents a high power density silicon carbide (SiC)-based inverter, with a two-level voltage-source structure having forced air cooling, which provides a high volumetric power density of 70kW/liter or 50kW/kg in gravimetric terms. In order to achieve a power density greater than that of conventional inverters, the losses must be reduced or the cooling performance must be improved. Small light-weight SiC MOSFET power modules with directly soldered foil fins having good thermal conductivities, are developed in this study. The antiparallel SiC Schottky barrier diodes (SBDs) are removed from the modules to improve the power density. Gate drivers are developed to reduce the switching losses and switching time. A prototype of the proposed high power density inverter, which includes the developed power modules and proposed gate driver, is fabricated. The volume and weight of the prototype inverter are approximately 0.5 liter and 660g, respectively. Experimental results confirm that the prototype inverter can operate continuously with an output power up to 35kW. Therefore, the power density of the prototype inverter is approximately 70kW/liter or 50kW/kg. The efficiency of the prototype inverter is found to be more than 98%. Hence, the measures undertaken in this study have been verified to improve the power density of the inverters. The proposed high power density inverters can be applied in future aircraft and other electric vehicles.