A Novel Solid-State Circuit Breaker With Robust Breaking Capability and High Efficiency

A novel solid-state circuit breaker with robust breaking capability and high efficiency is proposed for low-voltage dc microgrid protection. First, the proposed solid-state circuit breaker (SSCB) makes the commutation current flow inside the breaker. Thus, it can interrupt faults without reflecting current surges to sources or loads and effectively protect them. Second, by introducing the voltage clamping circuit, the proposed SSCB provides strong fault interruption capability even when encountering large parasitic parameters in microgrids. Third, the proposed SSCB provides fast reclosing and rebreaking capability due to the autorecharging of the commutation capacitor. Finally, the reverse voltage stress of the main power switch is greatly reduced through the magnetic coupling of the coupled inductor. As a result, the insulated gate triggered thyristor with field-stop layer (FS-IGTT), which features ultralow conduction loss and asymmetric blocking capability is designed and fabricated. By introducing FS-IGTT as the main power switch, the conduction loss of the proposed SSCB is reduced by 26% compared with SSCBs, which use nonpunch-through type IGTTs. In this article, the detailed operation of the proposed SSCB is discussed, and the design guidelines are presented through mathematical modeling. Moreover, a 400 V/4 kW laboratory prototype is built to verify the effectiveness of the proposed SSCB.