摘要
Circulating currents in a microgrid increase the power loss of the microgrid, reduce the operational efficiency, as well as affect the power quality of the microgrid. The existing literature is seldom concerned with methods to suppress the loop currents using fuzzy logic control. In this paper, a method based on fuzzy control of droop coefficients is proposed to suppress the circulating currents inside the microgrid.The method combines fuzzy control with droop control and can achieve the effect of suppressing the circulating currents by adaptively adjusting the droop coefficients to make the power distribution between each subgrid more balanced. To verify the proposed method, simulation is carried out in Matlab/Simulink environment, and the simulation results show that the proposed method is significantly better than the traditional proportional-integral control method. The circulating currents reduce from about 10 A to several nanoamperes, the bus voltage and frequency drops are significantly improved, and the total harmonic distortion rate of the output voltage reduces from 4.66% to 1.06%. In addition, the method used in this paper can be extended to be applied in multiple inverters connected in parallel, and the simulation results show that the method has a good effect on the suppression of circulating currents among multiple inverters.
微电网内部的环流会增加微电网的功率损耗,降低运行效率,以及影响微电网的电能质量。现有文献较少涉及利用模糊逻辑控制来抑制环流的方法。该文提出一种基于模糊控制下垂系数的方法来抑制微电网内部的环流,该方法将模糊控制与下垂控制相结合,通过自适应调整下垂系数,使每个子网之间的功率分配更加均衡,从而达到抑制环流的效果。为验证所提方法,在Matlab/Simulink环境下进行仿真,仿真结果表明所提方法明显优于传统的比例积分控制方法,环流从10 A左右降低到数纳安,母线电压和频率跌落情况也得到了明显改善,输出电压的总谐波失真率从4.66%降低到1.06%。此外,该文所用方法还可以拓展应用于多逆变器并联的情况,仿真结果表明该方法对抑制多个逆变器之间环流有良好的效果。
基金
Foundation items:National Natural Science Foundation of China(No.62303107)
Fundamental Research Funds for the Central Universities,China(Nos.2232022G-09 and 2232021D-38)
Shanghai Sailing Program,China(No.21YF1400100)。
