Snubber Branch Design and Development of Solid-State DC Circuit Breaker

This research proposes a solid-state dc circuit breaker for low voltage dc system based on reverse-blocking integrated gate-commutated thyristor (IGCT). The circuit breaker topology gets easier as a result of reverse-blocking IGCTs’ ability to withstand reverse voltage. To further enhance the breaking process, we develop a snubber branch with metal oxide varistors (MOVs) and capacitance. The advantages and disadvantages of three distinct snubber branches—the no-snubber, the resistance–capacitance (RC), and the MOV-C snubber branch—are then contrasted. In addition to suppressing high-frequency oscillation caught by the parasitic MOV parameters, the structure with MOV-C snubber branch also blocks low-frequency harmonics brought on by RC snubber branch. Moreover, this structure can slow down the rate at which the voltage rises during the breaking process. Comparatively speaking to the RC snubber branch and no-snubber branch structures, it is more appropriate for solid-state dc circuit breakers. Finally, a solid-state dc circuit breaker prototype based on RB-IGCT and MOV-C branch has been created. The maximum overvoltage is 1.5 kV and the rated voltage is 750 V. The maximum breaking current is 10 kA and the rated current can be 2 kA.