Efficiency Evaluation of an Automotive 800V HV/LV DCDC Converter Comparing IGBTs and SiC MOSFETs Semiconductors

Automotive HV/LV DC-DC converters, used in electric vehicles, demand high performance operation. One of the main contributors to converter losses are the high voltage power switching devices based on power semiconductor devices like IGBTs or Silicon Carbide (SiC) MOSFETs. Over the last few years, the industrial trend by replacing IGBT with SiC power devices is also visible for automotive industry. To highlight the performance improvement when using SiC MOSFETs, the paper presents a comprehensive comparison using three separate ways of power loss estimation: analytically, using simulation, and experimentally. The comparison assesses the reduction in switching losses, implicitly the gain in efficiency for an implemented 2.8kW automotive isolated 800V HV/LV DC-DC converter. The paper reveals the three methods necessary in the early phase of a power converter design which must be efficient and robust through all operating conditions.