A Progressive Switching Scheme for Solid-State DC Circuit Breakers

Achieving high-speed circuit protection is critical to direct current (DC) system safety. However, direct current circuit breaker (DCCB) fault isolation capability is limited by detection time and the transient surge voltage across the circuit breaker. In this project, a progressive switching scheme for solid-state DCCBs is proposed to suppress the fault surge while reducing component size and cost. We explore the dynamics of DC distribution systems to determine DC fault characteristics and analyze the voltage withstanding capabilities of power semiconductor devices. The device parameters and the progressive switching strategy have been incorporated in a computer simulation model and also experimentally validated with a test prototype. DC faults are isolated safely while placing less strain on DCCB components and drawing less fault current facilitating the use of smaller and more efficient switches to reduce cost and power consumption.