Autonomous control strategy of bidirectional AC/DC converter in low voltage hybrid microgrid

摘要

Bidirectional AC/DC converter is particularly important for the hybrid microgrid. Based on the analysis of power droop characteristics of low-voltage microgrid, an autonomous operation control strategy for bidirectional AC/DC converters in low voltage hybrid microgrid is proposed in this paper. The AC/DC microgrids bus voltage is normalized according to the fluctuation range of sub-microgrid voltage. The P-V droop control of bidirectional AC/DC converter is designed to make the normalized bus voltage of AC and DC sub-microgrids the same and bus voltage within the allowable range. With making full use of the remaining capacity of the bidirectional AC/DC converter, the Q-δ droop control is designed to maintain the frequency stability in the AC sub-microgrid, which has not yet been investigated before, and would certainly rely on the coordinated operation of DC sources, AC sources, and interlinking converters. Simulation results verify the availability of the proposed control strategy.