Protection of DC system using bi-directional Z-Source Circuit breaker

Modified topologies of a Z-Source DC Circuit breaker with bi-directional power flow capabilities are introduced in this paper. Conventional Z-Source breaker (ZSB) topologies can provide protection for unidirectional power flow. Proposed topologies of bi-directional ZSB (Bi-ZSB) and bi-directional ZSB with coupled inductor (Bi-CZSB) can clear the fault in either direction of power flow. Both topologies utilize a SCR as a switch to instantly isolate the fault from source. No sensing and detection of fault is required. For second topology, mutual inductance is used for SCR commutation. Coupled inductors help to reduce size of inductors, cost and also eliminate the need of additional Z-Source breaker capacitor. Performance of both topologies is verified in MATLAB and validated on laboratory prototype.