交直流微电网AC/DC双向功率变换器控制策略

Bidirectional AC/DC interlinking converter control strategy for an AC/DC microgrid

为了实现交直流混合微电网的可靠并网,基于微电网中AC/DC双向功率变换器下垂控制策略和预同步工作原理,提出一种适用于混合微电网中连接交直流子网的AC/DC双向功率变换器的控制策略。孤岛/并网模式时采用双向下垂控制实现双向功率流动。在由孤岛模式转为并网模式时,利用消除dq轴电压偏差实现幅值与相位同步,无需通过锁相环获取相位信息,实现平滑并网。同时,针对微电网中由于不平衡负载导致的三相不平衡工况,采用正负序分别控制的方法实现了非理想工况下微电网的同步互联。仿真结果验证了该方案的可行性。

In order to realize the reliable grid connection of an AC/DC hybrid microgrid,a control strategy for a bidirectional AC/DC interlinking converter connected to an AC-DC subnet in a hybrid microgrid is proposed based on a droop control strategy in the microgrid and a pre-synchronization working principle.In the island/grid-connected mode,the bidirectional droop control is used to achieve bidirectional power flow.When the island mode is changed to the grid-connected mode,the amplitude and phase synchronization can be realized by eliminating the voltage deviation of the dq axis without obtaining phase information through phase-locked loop to realize smooth grid-connection.At the same time,for the three-phase unbalanced conditions caused by an unbalanced load in the microgrid,the method of positive and negative sequence control is adopted to realize the synchronous interconnection of the microgrid under non-ideal conditions.Simulation results verify the feasibility of the proposed scheme.