交直流微电网AC/DC双向功率变换器控制策略

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。

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

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. This work is supported by Natural Science Foundation of Shanxi Province (No. 201701D121134), National Natural Science Foundation of China (No. U1610121) and Science and Technology Grant Program of Shanxi Province (No. 20181102028).