SOA measurement of SiC MOSFETs using different voltage clamping techniques in DC SSCB

DC systems have received a lot of attention in recent years for their superior performance and reliability compared to AC systems, especially in applications such as DC microgrids, electric aircraft, battery protection, photovoltaics, and marine power distribution. DC semiconductor circuit breakers (DCCBs) using SiC MOSFETs are an ideal solution for these systems because they offer high input speeds. However, little is known about the performance and reliability of SiC MOSFET under DCCB conditions, especially the different voltage stabilization techniques. There are three main contributions of this article. First, evaluate the safe operating area (SOA) and characteristics of SiC MOSFET for DCCB applications, focusing on three voltage clamping methods: RCD, MOV, and a combination of both. Second, it provides a comprehensive quantifying investigation of the drain–source current I d . The RCD method can interrupt currents up to 5.25 times the rated current in single-pulse tests, while the MOV method supports up to 4.83 times, and the combined method up to 4.6 times. Third, in repetitive tests, the RCD, MOV, and combined methods sustained 1122, 2078, and 2842 interruptions, respectively, at 2.25 times the rated current. The total energy over the lifespan is 11.62MJ for the RCD, 21.52MJ for the MOV, and 29.44MJ for the hybrid RCD-MOV. Thermal failure was the primary cause of degradation. The findings emphasize the need for optimized voltage clamping strategies to improve the performance, reliability, and SOA of SiC MOSFETs in DCCB applications. • RCD, MOV, and hybrid RCD–MOV clamping methods are compared for SOA improvement in SiC MOSFETs. • The hybrid RCD–MOV clamp suppresses voltage spikes and improves stability during DC fault interruption. • RCD clamping achieves up to 5.25× rated current interruption in SiC MOSFETs under single-pulse tests. • Experiments confirm extended SOA and improved long-term reliability using optimized clamping methods.