When a short-circuit fault occurs, the inverter will switch from the voltage control mode (VCM) to the current control mode (CCM), limiting the output current to the set value to cooperate with the action of relay protection device of fault branch. After the fault is removed, the inverter switches to the voltage control mode to quickly recover the output voltage and reduce the power-off time. However, sudden applied voltage may produce inrush current with large amplitude which will cause output voltage distortion and even cause damage to the transformer. Therefore, an inrush current suppression method is proposed in this paper. This method extracts the asymmetric component formed by inrush current by calculating the average value of transformer primary side current of each fundamental period. Using it as the negative feedback input of inrush current controller to suppress inrush current. Simulation and experiment results verify the feasibility of this method.

inrush current; inverter; short-circuit; suppression; transformer