An Improved Fault Current Bypass-Based DC Solid-State Circuit Breaker for DC Microgrid Applications

Solid-state circuit breakers (SSCBs) have gained traction in the protection field due to their fast fault interruption and arcless operation. This paper proposes an improved fault current bypass-based DC SSCB for DC microgrids. The proposed topology features fast fault isolation and cost-effectiveness. Initially, the superiority of the proposed topology is analyzed in comparison to two prior-art fault current bypass-based topologies. Next, the operating principles and key design considerations are presented for the proposed topology. Finally, the effectiveness of the proposed topology is verified through both simulation and experimental results. The proposed topology is the most cost-effective solution, with 99.82% efficiency and a 15% cost reduction for power semiconductor selection compared to the other two traditional fault current bypass-based topologies. Experimental results from a 400 VDC/80 A prototype demonstrate the feasibility of the proposed topology, showing that the clamping voltage of the metal oxide varistor (MOV) is lower than the DC voltage.