The Crowbar Clamping Circuit to Reduce the Surge Voltage in the DC Solid-State Circuit Breaker

The surge voltage caused by the metal oxide varistor (MOV) characteristics easily damages semiconductor switches in the DC solid-state circuit breaker (SSCB). This paper presents a surge voltage suppression method for DC SSCB using a crowbar clamping circuit by splitting the overvoltage protection into three separate varistors. The lower DC-rated voltage of double varistors serially optimizes for the surge voltage protection allowed by the voltage divider circuit of two resistors. After theoretical analysis, it is verified by computer-aided simulations.