A Low-Loss Z-Source Circuit Breaker for LVDC Systems

Conventional bidirectional Z-source circuit breakers (Bi-ZSBs) require at least two semiconductor tubes to be turned on during the normal operation, which is typically a series connection of a thyristor (SCR) and a power diode. The conduction loss of the semiconductor tube is not negligible in the case of dc high power since it is approximately proportional to the current flowing through the semiconductor tube. Therefore, this article presents a new low-loss Z-source circuit breaker for LVdc systems. In the normal operation, the proposed topology has only one thyristor turned on, so it further reduces the conduction loss of the Bi-ZSB compared with the conventional Bi-ZSBs. In addition, the proposed topology uses a coupled inductor with two windings, which has the characteristics of simple structure, small volume, common ground, and so on. The working principle and power loss of the proposed topology is analyzed in detail, and the circuit design is given. Finally, the performance of the proposed topology is verified by MATLAB simulation and hardware experiments.