A Single-Drive SiC-JFET-SCM for Solid State Circuit Breaker in MVDC Distribution Networks

Solid-state circuit breaker (SSCB) has the advantages of fast response, strong controllability, and no arc cutting in dc fault clearance, but it also has the problem of cascaded voltage unbalance in the medium voltage direct current distribution networks. First, this article proposes a single-drive topology of silicon carbide junction field-effect transistor super cascade module (SiC-JFET-SCM). Then, the turn-OFF process of the SiC-JFET-SCM is analyzed in detail by establishing the mathematical models. It is found that the resistance-capacitance circuits (RC) networks can affect the action process of SiC-JFET-SCM, leading to the difference in OFF-time between traditional analysis and actual work. Finally, based on that, the critical parameters are calculated to provide a theoretical basis for the device selection. A 3.3 kV/63A SSCB based on SiC-JFET-SCM is designed, which can identify faults precisely, and achieve a better dynamic and static voltage balance. Experimental results verify the effectiveness of the designed SSCB under different fault conditions.