Performance of a 500A, Unidirectional IGCT-based Solid-State DC Circuit Breaker for Electric Vehicle Charging Applications

Modern electric vehicle (EV) charging infrastructure (EVCI) needs to deliver large currents from the grid to external car chargers / on-board chargers for two reasons: the first being due to the rising battery sizes stemming from increased EV range; the second due to the customer expectations for EVs to have shorter charging times on par with fueling times of fossil-fuel-based vehicles. Fault currents in a DC charging system are difficult to interrupt due to the absence of a natural current zero-crossing and a higher fault-di/dt caused by lower system inductance values. Hence, such an EVCI system would also need a protection device capable of rapidly interrupting large short-circuit fault currents with extremely high fault-di/dt, in addition to an overload protection function for slower current transients. This digest investigates the performance of a 1kV, 500A solid-state circuit breaker (SSCB) designed for grid-to-vehicle fast charging applications, focusing on its capabilities in interrupting large short-circuit currents under high fault-di/dt conditions as well as on its unique “diode-blocking” operation mode.