An Automated Optimal Design Procedure of a Nonlinear Inductor-Based Hybrid Dc Circuit Breaker

Medium voltage dc power system is a promising solution for various applications, while it still suffers from an issue of short-circuit fault management. A hybrid dc circuit breaker with a piezoelectric actuated fast mechanical switch (FMS) has been developed to overcome the issue. To extinguish fault current as fast as possible and achieve arc-less opening of the mechanical switch, a novel nonlinear inductor-based fault current commutation strategy was developed. This paper introduces an automated optimal design procedure for a fault current commutation circuit, including the nonlinear inductor, in the hybrid breaker. The design procedure has multiple objectives: minimizing fault current commutation speed, maximize the zero-current period for the FMS, and minimizing the energy stored in the inductor. Simulation results verify the effectiveness of the automated optimal design procedure.