Wide-Bandgap Solid-State Circuit Breakers for DC Power Systems: Device and Circuit Considerations

TLDR

DC circuit protection offers a unique market opportunity for wide‑bandgap semiconductors beyond conventional power electronic converters. The paper reviews emerging DC power systems and the need for solid‑state circuit breakers, proposing self‑powered SiC or GaN normally‑ON SSCBs. The SSCB senses a voltage rise across its drain‑source, uses fault‑derived power to shut a SiC JFET, and is implemented in unipolar and bipolar forms with SiC and GaN devices. An experimental 1200 V SiC JFET SSCB cut a 125 A fault current at 400 V in 1 µs without external power, confirming that low‑ON‑resistance normally‑ON WBG devices are ideal for SSCBs.

Abstract

DC circuit protection applications provide a unique market opportunity for wide-bandgap (WBG) semiconductors, which are outside the conventional focus on power electronic converters. This paper presents an overview of emerging dc power systems, the needs for dc solid-state circuit breakers (SSCBs), and the benefits and advantages of various WBG SSCB concepts. Furthermore, a new class of self-powered SSCBs based on SiC or GaN normally-ON switching devices is proposed in this paper. One implementation of the SSCB concept based on a 1200 V SiC JFET experimentally demonstrated turn-off of a fault current of 125 A at a dc voltage of 400 V within 1 μs without requiring any external power supply. The SSCB detects short-circuit faults by sensing its drain-source voltage rise and draws power from the fault condition to turn off the SiC JFET. Various implementations of the SSCB concept for unipolar and bipolar capability using both SiC and GaN are also discussed from both device and circuit perspectives. It is concluded that very low ON-resistance normally-ON WBG switching devices are excellent candidates for the emerging SSCB applications.