关键词: 孤岛模式, 下垂控制, 虚拟功率, 控制策略, 负荷分配

Abstract: Considering an intensive coupling between the active and reactive power because of resistive line impedance in microgrids, the generation units adopting traditional V/f droop-control strategy can’t effectively achieve the distributed power source’s output power varies as the load power changes in island mode. The paper proposed a coordinate rotational transformation based on virtual power V/δ droop control strategy to achieving load distribution in islanded operation with distributed generation units. The strategy achieves the decoupled active and reactive power control through orthogonal transformation matrix, and the output power limiting measures feedback function and derivative function employs additional derivative terms with modified gain respectively, which guarantee stability and good transient response and load sharing in microgrid. The Matlab simulation results verify that the proposed control strategy is feasible for increasing or cutting load and cutting one distributed generator in islanded microgrids.

Key words: islanded operation, droop control, virtual power, control strategy, load distribution