A 4kV/100A SiC MOSFETs-based solid state DC circuit breaker with low stray inductances and powered by a load-independent wireless power transfer system

This paper develops a 4kV/100A DC circuit breaker (DCCB) based on discrete SiC MOSFETs. The DCCB adopts a 5-layers tower structure and each layer has ten evenly distributed MOSFETs. The DCCB is powered by a wireless power transfer (WPT) system with multiple outputs and easy to scale. The DCCB we proposed has two main advantages. First, it has very low normally on-state power loss compared to traditional solid state breakers. The on-state efficiency is higher than 99.97%. Second, compared to the previous power supply system for the DCCB, the implemented WPT system has a good load-independent characteristic. The maximum efficiency of this WPT system is 87%, with a total power of 40 W at 200 kHz. Besides, An accurate equivalent model of the DCCB is established by including mutual inductances among different MOSFETs. According to this model, the mutual inductance could count on 40% of the total parasitic inductance.