Experimental Evaluation of a SiC MOSFET in Surface Mount Power Device Package

Inhalt:
Switching loss is an important factor affecting the efficiency of high frequency DC-DC converters in electric vehicle (EV) applications. The aim of this study is to determine the switching performance and the maximum current capability of a half-bridge SiC MOSFET module used in EV DC-DC converters. The SiC MOSFETs are packaged in surface mount power device or SMIT package. Switching transients are analyzed using double pulse test (DPT) experiments at 100 V input voltage and 10-30 A current range. Although, due to the faster switching capability of SiC MOSFET switching losses were expected to be quite low, it was found that the experimental switching losses were significantly high because of the parasitic elements of the package and the circuit. It was also found that SiC MOSFET switching losses are comparable for both SMIT and TO247 packages. On-state performance of the selected SiC MOSFET was also verified by detailed thermal simulation and experiments. Experimentally measured losses were used to conduct the loss-breakdown of a 12 kW bidirectional DC-DC converter based on the SiC MOSFET. The efficiency in both buck and boost modes has been predicted to be over 97%.