微电网下垂控制的运行策略及PCC处联络功率控制

Droop Control Strategies for Microgrid and Power Control at PCC

采用了虚拟阻抗及二次调频调压的下垂控制方法作为微电网独立运行时的控制策略。通过基于αβ坐标系下的快速相位同步方法来加快逆变器并入微电网或微电网并入大电网的速度。当微电网处于并网运行时,采用αβ坐标系下的PQ控制将各微电源控制为电流源。在此基础上,通过采用公共耦合点PCC(point of common coupling)处的联络功率控制策略,实现微电网并网运行时与大电网间的联络功率控制。根据搭建的MATLAB仿真模型对上述控制策略进行了仿真,最后对上述控制策略进行了实验验证。

In this paper, an improved droop control method based on virtual impedance and secondary frequency- modulation voltage-modulation control is adopted as the control strategy when a microgrid is operating in standalone mode. In addition, a fast phase synchronization method implemented in the αβ frame is used to speed up the synchronization between inverters and the microgrid and between the microgrid and the grid. When the microgrid is operating in grid-connected mode, a PQ control strategy under the αβ frame is applied to control different micro-sources as current sources. On this basis, a power control strategy is applied at the point of common coupling ( PCC ), thus realizing the control of power between the microgrid and the grid. A simulation model was built in MATLAB to simulate these control strategies, which were experimentally verified at last.