Investigating the Stability of a DC Shipboard Microgrid protected with Solid-State Circuit Breaker

DC microgrids represent a valuable solution for the realization of shipboard power systems. However, protection of dc microgrid is challenging: the absence of zero crossing of dc currents and the fast response of new technologies of energy storage system such as supercapacitor and batteries introduce strict requirements on the circuit breaker performances, making the conventional electro-mechanical circuit breaker not suitable for these applications. For these reasons, the solid-state circuit breaker is one of the most promising solutions. However, this component requires the presence of a current-limiting inductor, for limitation of the maximum value of fault current, whose effect in the normal operation of the system has not been addressed in literature. This work aims to identify, through an analysis of the impedance ratio in the point of coupling and real-time simulations, the presence of a potential resonance in the dc-bus of a notional dc microgrid. Different study cases have been considered, varying the value of the inductive fault current limiter, demonstrating the need to further investigating this phenomenon.