交直流混合微电网分段协调控制策略

为解决交直流混合微电网因微源出力变化、负荷变化和储能装置因荷电状态导致充放电功率发生变化等引起的功率波动问题,提出一种混合微电网分段协调控制策略。针对孤岛状态下的混合微电网,分析了混合微电网的典型拓扑和各运行模式下的功率关系。采用标幺化的方法得到了可表征混合微电网整体运行状态的特征量,根据该特征量的变化量对控制策略进行分段,对各段控制的工作原理进行了详细的分析,具体研究了在不同控制段中各变流器的相互协调;针对可能出现的网间交换功率振荡以及互联变流器(ILC)运行模式频繁切换的问题,对动作判据进行了补偿。最后,在PSCAD/EMTDC中建立了仿真模型,仿真结果表明,在不同工况下各变流器均可迅速做出响应,保证系统的稳定运行。

Segmented Coordination Control Strategy for Hybrid AC/DC Microgrid

In order to solve the power fluctuation caused by the change of micro-source output, loads and charging and discharging power of energy storage devices because of state of charge in hybrid AC/DC microgrid, a segmented coordination control strategy for hybrid microgrid is proposed. Aiming at the hybrid microgrid in the islanded state, the typical topology of the hybrid microgrid and the power relations in different operation modes are analyzed. The characteristic quantity which can represent the whole operation state of hybrid microgrid is obtained by the standardization method. According to the variation of the characteristic quantity, the control strategy is divided into segments. Then the working principle of each section control is analyzed in detail and the coordinated control of the converters in different control segments is studied. Aiming at the possible power oscillation in microgrid and frequent switching of operation modes for interlinking converter (ILC), the action criterion is compensated. Finally, a simulation model is established in PSCAD/EMTDC. The simulation results show that all converters can respond quickly in different operation conditions to ensure the stable operation of the system.