模式转换下分布式电源接入微电网的控制策略研究及仿真

Study and simulation of the distributed power access to the micro-grid under mode switching

分布式电源的建模及微电网的控制策略是当前的研究热点,针对模式转换下分布式电源接入微电网控制策略选择的研究较少。孤岛和并网模式下应选择不同的控制策略,同时在一个微电网中加入多种分布式电源的控制复杂,难度比单一分布式电源接入要大。文章分析了微电网的特殊性,进行了不同的控制模式的比较。孤网时选择主从控制模式作为微电网的控制策略可以适应微电网不同运行方式的需要;并网时分布式电源可采用PQ控制。根据在并网模式下的运行特点提出各个分布式电源的PQ控制策略,建立了含光伏电池、风力发电机、微型燃气轮机的微电网模型。仿真分析了孤岛运行下和日照环境改变时微电网的并网运行特性,结果证明了控制方式的恰当选择能使微电网在不同运行模式下对于大电网可控且动态性能优良,并网时不会对大电网产生大的冲击。

A number of recent researches have focused on the modeling of distributed power and control strategies of the micro-grid, but there are fewer studies of the control strategy choices on the distributed power access to the microgrid under mode switching. Different control strategies are needed under the islanding and the grid-connected modes. Meanwhile, the control on the access of multiple distributed power to the micro-gird is more difficult than that on the access of the single distributed power. This paper analyzed the particularity of the micro-grid and compared different control modes. Under the islanding mode, the master-slave control mode could be chosen as the control strategy of the micro-grid so as to satisfy the need of the micro-grid for different operating modes, while under the grid-connected mode, the distributed power could adopt PQ control. PQ control strategies for various distributed power were proposed according to the operating features of the grid-connected mode. The simulation model of a micro-grid.containing photo- voltaic cells, wind turbines and micro-turbines was built. The operating features of the paralleling micro-grid were simulated and analyzed under the islanding mode and while light intensity changed. The results proved that the proper choice of control methods could guarantee the controllability of the micro-grid and excellent dynamic performance un- der different modes, and the access to the micro-grid would not have a great impact on the power system.