Low-loss bi-directional Z-source solid state circuit breaker based on discrete inductors

DC solid-state circuit breakers are becoming increasingly critical to the safety of DC microgrids. However, the currently proposed solid-state circuit breakers have problems such as high loss, large volume and weight, and reflected current on the source side. In order to solve the above problems, this paper has carried out the research of low-loss bi-directional Z-source solid state circuit breaker (BZSCB) based on discrete inductance. Firstly, the traditional BZSCB topology derivation method is analysed, and a new low-loss BZSCB topology based on discrete inductance is derived. Then, the working principle of the proposed new BZSCB topology is introduced, and its impedance network characteristics are revealed. Then, the relationship between the minimum detectable fault conductance, the minimum detectable fault rise rate and the Z-source impedance network parameters of the new circuit breaker is deduced and analysed, and the design method of capacitance and inductance parameters is given. Finally, the fault isolation function of the new circuit breaker is verified by Saber simulation.