基于电池储能和可控负荷的孤岛型海岛微电网频率协调控制策略

针对以风电和波浪能发电为主电源的孤岛型海岛微电网,提出一种基于电池储能和可控负荷的孤岛型海岛微电网频率协调控制策略。储能元件采用改进的下垂控制实现类似于电力系统一次调频的有差调频,根据其荷电状态及最大充放电功率,动态调整下垂控制运行点以及下垂控制系数,既能将微网频率偏差控制在合理范围内,又能防止电池储能系统过充过放;利用海水淡化负荷的可控性,将频率偏差引入其转速控制环,实现类似于电力系统二次调频的无差调频。在Matlab/Simulink下搭建了孤岛型海岛微电网的仿真模型,并对不同运行场景进行了仿真验证。结果表明,基于电池储能和可控负荷的孤岛型海岛微电网频率协调控制策略可以有效地分配系统功率差额,维持海岛微电网的频率稳定。

Coordinated control strategy for the islanded microgrid with battery and controllable load

For the islanded microgrid based on wind and wave energy, a coordinated frequency control strategy with Battery Energy Storage System(BESS)and controllable load is proposed to improve the frequency stability. A novel droop controller is implemented in BESS to achieve primary frequency regulation. In the proposed droop strategy, the stable running point and droop gain are dynamically adjusted according to thestate of charge(SOC), to prevent the over-limitation of frequency, over charge and discharge of BESS. Moreover, controllable loads such as seawater desalination is served as a secondary frequency regulator. And then, frequency error is sent into PI controller to acquire the power reference of controllable loads so that the stable frequency error can be eliminated. Finally, the simulating model of islanded microgrid is built with Matlab/Simulinkand simulation verification is performed underdifferent operating scenarios. The results show that the coordinated frequency control strategy can effectively maintain the power balance and frequency stability of the islanded microgrid.