A Coupled Inductor-Based SSCB With Reduced Components for DC Microgrid Protection

DC microgrids have gained importance for their high efficiency, no need for synchronization, high power quality, and potential to reduce greenhouse gas emissions. Ensuring reliable and fast protection against over current and short-circuit faults is considered to be a challenge even to date. Solid-state circuit breakers (SSCBs) offer a promising solution, providing rapid and arc-less fault clearing. However, SSCBs employing fully controlled devices lead to higher costs and conduction losses. This article discusses a cost effective circuit breaker, using a semi-controlled switch based on a coupled inductor. The proposed SSCB has reduced overall components, a discharged capacitor and also allows the option to trip manually for maintenance. A detailed analysis and design methodology for component selection is presented in the later sections. The SSCB is experimentally validated by developing a laboratory prototype for a voltage rating of 400 V and at a nominal current of 15 and 20 A with a short circuit fault current of 60 A.