Design of a DC Miniature Solid-State Circuit Breaker and Impact Analysis of Stray Inductance

Abstract

With the advantages of DC micro-grid becoming increasingly prominent, because the traditional miniature circuit breaker cannot satisfy the requirements of fast breaking, the miniature solid-state circuit breaker has become a good solution. However, the design of miniature solid-state circuit breaker is faced with challenges such as cost, volume, conduction loss, etc. This paper presents a design scheme of DC miniature solid-state circuit breaker and analyzes its working principle. The main circuit uses two parallel SiC MOSFETs as the main devices, reducing the conduction loss. Under fault conditions, the power electronic devices are disconnected at the same time, and the current can be transferred quickly through the buffer absorption branch. The drive circuit and buffer absorption circuit are designed. The simulation model is built in Pspice to analyze the influence of the stray inductance of each branch on the energy generated by turn-off, turn-off speed and turn-off overvoltage. Considering the influence of stray inductance, a prototype of miniature DC solid state circuit breaker is designed. The experimental results show that the circuit breaker can turn off quickly and stably, and the buffer absorption circuit can well suppress the turn-off voltage spike, which verifies the rationality of the design scheme.