An Adaptive Coordinated Constant Voltage Control Method Considering Power Margin for Parallel Bidirectional Power Converters in AC/DC Hybrid Microgrid

Parallel bidirectional power converters (BPCs) play an important role in achieving mutual support between AC and DC grids and in improving the power quality. Rather than distributing the steady state transmission power evenly among parallel BPCs, it was identified that optimal distributing the power according to the efficiency curve of each BPC is more beneficial, which can reduce the total steady state power loss of BPCs and can improve the economy of the AC/DC hybrid microgrid. In view of this, this paper proposes an adaptive coordinated constant voltage control method considering power margin for the BPCs. The method can realize the economically optimal power distribution among BPCs in steady state, to improve the economy of system operation. In case of power disturbances, the transient transmission power can be distributed adaptively among BPCs according to the power margin of each BPC, meanwhile ensure the DC area operation with the rated voltage, so as to improve the voltage quality of the system and avoid BPC overload. The effectiveness of the proposed control method is illustrated and the conclusions are verified by simulation and Hardware-in-loop tests.