A 400V/300A Ultra-Fast Intelligent DC Solid State Circuit Breaker Using Parallel Connected SiC JFETs

The increasing load density of direct current (DC) distribution system leads to an increase in system capacity and short-circuit fault current. However, due to the limited capacity of a single semiconductor device, solid state circuit breaker (SSCB) with one semiconductor device is difficult to apply to high current applications. This paper proposes a 400V/300A intelligent SSCB with 8 parallel normally-on SiC JFETs as the main static switch, a Microprocessor Unit (MCU) as the intelligent controller and a fast-starting isolated DC/DC converter as the protection driver. This article focuses on Current sharing and balancing among the parallel SiC JFETs. The short circuit experiment was performed using the designed SSCB prototype. The experimental results show that the proposed SSCB can realize short-circuit protection in several microseconds and overload protection in several hundred microseconds. In addition, good dynamic and static current sharing effect is achieved in this paper.