Collaborative control strategy of power electronic transformer and fault current limiter in DC microgrid

Abstract

With rapid development of DC microgrid (DCMG), the protection against short circuit fault on the whole DC system has gained widespread concern. This paper proposes an approach which uses power electronic transformer (PET) and fault current limiters (FCLs) to improve the impact of short circuit current in DCMG. FCL in the fault line can work in the fault current limiting mode to limit short circuit current in this line. PET adjusts the input power from AC grid to DC grid to keep the DC voltage stability in the DCMG. A complete model of PET and DCMG is developed and the collaborative control strategy of PET and FCL is analysed. The simulation results confirm that the proposed control strategy based on the collaborative operation of PET and FCL can enhance the ability to ride through the short circuit fault of each part of DCMG system.