A 2 kV Intelligent DC Solid State Circuit Breaker Using Series Connected SiC JFETs

This paper presents a self-powered solid state circuit breaker (SSCB) for medium voltage DC distribution systems with three cascaded normally-on SiC JFETs as the solid state switch and a microprocessor as the gate driver. The SSCB can draw power directly from the DC bus without any external auxiliary DC power source. The designed gate driver circuit achieves a dynamic and static balancing of the voltage distribution between the cascaded SiC JFETs during fault isolation. In addition, in order to verify the function of the proposed SSCB, a 2 kV SSCB prototype is built. The experimental results suggest that the proposed SSCB can realize comprehensive protection for different fault situations to prevent the mal-operation of SSCB possibly caused by capacitive load start-up.