基于微电网逆变器改进下垂特性协调控制的研究

Research on the coordination control of the improved droop characteristics for microgrid inverters

由于采用传统下垂控制策略的微电网孤岛时受负载变化影响和并网时受大电网扰动影响会造成系统不稳定,文章提出了改进下垂控制策略,机理是在原下垂控制的基础上改变下垂特性的参考电压和频率和引入了前馈电流调节机制,加快了系统响应速度,增加了微电网系统稳定性。最后利用PSCAD/EMTDC仿真软件对微电网两种典型运行状态以及模式切换的暂态过程进行仿真分析,验证了控制策略的合理性与有效性。

The microgrid controlled by the conventional droop strategies can result in the instability of the microgrid due to the influenced of the load change in the island mode and that of the main grid disturbance in the grid-connected mode,so this paper proposed an improved droop control strategy. The principle of the strategy was to change the reference voltage and frequency of the droop control characteristics and to introduce the regulation mechanism of the feedforward bias current based on the conventional droop control. This strategy could speed up the response of the system and increase the stability of the whole system. Finally,simulation and analysis were made to the two typical running modes of the microgrid and the transient process of mode switch with the simulation software PSCAD / EMTDC,and the rationality and effectiveness of the proposed control strategy was verified.