Design and Development of DC Inductor for Hybrid Circuit Breaker Protection

With the advances in semiconductor technology like wide band gap-based power electronics, there is an increased focus on hybrid circuit breakers (HCBs) instead of the traditional mechanical circuit breakers to improve the response time to fault currents. These HCBs play a critical role in protection of electrical systems like DC microgrids. However, HCBs suffer from reliability and life reduction if exposed to very high rates of current rise during the initial transients. This paper proposes a DC inductor placed in series with the HCBto reduce the rate of current rise. In this work electromagnetic simulations have been performed on various inductor designs to finalize the type of core, its height and the number of copper winding turns based on performance metrics like inductance and limiting current. The finalized inductor design has also been analyzed using coupled electromagnetic-thermal analysis (finite element analysis) to ensure that the design meets temperature limits for all the materials. The inductor design has been prototyped and tested to validate the results of thermal simulations.