Predicting potential of 4H-SiC power devices over 10 kV

This paper presents the theoretical assessment of conversion losses for 4H-SiC based power devices over 10 kV. A set of empirical and analytical equations are developed to predict the losses at different temperatures and over wide blocking voltage range. Basic data for empirical equations in terms of R_ON and knee voltage of bipolar devices (i.e., IGBTs, PIN dioode) is also compared with the experimental results and shows fairly well qualitative agreement. The conduction and switching losses for SiC-IGBTs are far superior to Si based IGBTs upto 6.5 kV. Compared to MOSFETs, SiC-IGBTs show superior performance over 10 kV predicted from present simple analysis. These set of handy equations provide a quick insight into the device physics and useful guidelines for designing converter valves/cells for high power ratings.