低压微网控制策略研究

Control Strategy Research on Low Voltage Microgrid

为了避免微网运行模式变化时控制策略的切换,实现微网的平滑过渡,对传统的P-f和Q-V下垂控制进行改进,实现了并网运行时基于下垂控制的间接恒功率控制方式。并在脱网过程中采用了控制参数自动调节机制,以减小微网大功率不匹配引起的电压波动。分析了基于频率和幅值参考值正反馈的同步并网控制原理,在维持分布式电源输出功率的前提下利用下垂控制完成微网的同步并网。低压微网仿真结果表明,提出的控制方法能够有效地加快脱网过程中的电压调节速度,实现孤岛运行微网的平滑并网,降低运行模式变化给微网带来的冲击。

In order to avoid the switch of control strategies and achieve the smooth transition when operating modes change, the typical droop control based on P-f and Q-V characteristics was improved in this paper. And the parameter automatic adjustment was applied to reduce the voltage fluctuation caused by the power mismatch in the microgrid. At the same time, the method of grid synchronization control based on the positive feedback was analyzed to achieve microgrid reconnection to the power network while maintaining the output power of distribution generators （DGs）. The simulation results of low voltage microgrid show that the proposed control methods speed up the voltage control when islanding occurs, complete the smooth reconnection of the microgrid and reduce the impact on the microgrid when ooerating mode changes.