Performance Analysis of Counter-Current Injection based DC Circuit Breaker with Improved Capacitor Charging Circuit

In this paper, a hybrid DC breaker topology based on counter current injection method [1], [2] with improved charging circuit of the capacitor is proposed and analyzed. Instead of using an external source to pre-charge the capacitor, the proposed charging circuit uses the system voltage. The charging circuit is implemented with only one semiconductor switch compared to two switches charging circuitry that is used in general to isolate both positive and negative terminal of the source voltage from the capacitor terminals. The paper proposes a modified snubber circuit to avoid overvoltage across the circuit-breaker. Effect of snubber capacitance and snubber resistance on the circuit performance is also analyzed.