An Automatic and Self-Powered Solid-State DC breaker with Normally-ON SiC JFETs

This paper proposes an automatic and self-powered solid-state DC circuit breaker employing normally-ON silicon carbide junction-field-effect transistors. These devices exhibit low power conduction losses compared to silicon counterparts, which makes them suitable for solid-state DC circuit breakers. The proposed circuit not only eliminates the need for external gate power supply, but it also eliminates the use of fault detection circuits and thus, an increased reliability of the breaker can be achieved. Simulation results show that the proposed breaker concept is able to clear a fault current of 80A within 51mus. Additionally, a lab prototype of the solid-state breaker was designed and tested. The experimental results validated the proposed scheme, clearing a current of 33A in 330mus.