Dynamic Voltage Balancing for the High-Voltage SiC Super-Cascode Power Switch

Presented in this paper is an optimization method to improve the dynamic performance of high-voltage supercascode power switches (SCPSs) by implementing silicon carbide (SiC) junction field-effect transistor (JFET). The basic operating principle of SCPS is explained at the beginning of the paper. Equivalent circuit models are outlined next, with equations describing the voltage distribution among each SiC JFET during switching transients. Based on the sensitivity analysis, a component optimization method for balancing the SCPS internal voltage is proposed, which effectively eliminates the overvoltage. This significantly reduces the switching loss and the chance of diode avalanche. Compared with the nonoptimized case, the turn-on loss of the SCPS is reduced to 8.85%, and the turn-off loss reduces to 48.4%.