A Current Limiting Strategy for WBG-Based Solid-State Circuit Breakers With Series-Connected Switching Cells

The current limiting function enables the solid-state circuit breaker (SSCB) to have proper protection coordination. It allows sustained overcurrent for a certain period while preventing the fast fault current increase in dc systems. For the conventional method of using switches alone to limit the current, the high loss results in a short withstand time and low current limiting capability of the SSCBs. In this letter, a control strategy is proposed to utilize the energy absorption component to handle the major part of the energy during the current limiting stage to increase the current limiting capability for series-connected SSCB switching cells. The proposed method is experimentally verified to have more than 3X current limiting withstand time compared to the conventional control strategy in a case study.