基于变论域模糊控制的MPPT控制策略

MPPT Control Strategy Based on Theory of Variable Universe Fuzzy Control

传统最大功率跟踪(MPPT)方法如电导增量法存在较大稳态误差和波动,加入模糊控制后,虽然系统的动态性能有所改进,但由于模糊论域固定,控制还是略微粗糙,稳态时存在波动。文章采用变论域模糊控制对MPPT进行控制,其优点是不需要过多经验来设定规则表,通过输入改变伸缩因子从而改变论域的范围,使控制更加灵活,缩短了响应时间,缩小了稳态误差和波动,从而保护光伏负载,极大提高太阳光利用率。分别在固定环境和变化环境中对系统进行仿真,从输出功率和负载电压两方面对变论域模糊控制的优越性进行论证。

Traditional methods of maximum power point tracking （MPPT） control like conductance increment method have disadvantages of larger static error and fluctuation, while after adding fuzzy control, the dynamic performance of the system can be improved, but as the universe of the fuzzy controller is fixed, the control is rough and the fluctuation is still big relatively. In this paper, the variable universe fuzzy control method is used in MPPT control. The advantages of this method are that the settings of rule tables need less experience, and the variable universe is obtained by changing the input scaling factors, so as the control is more flexible, the response time is shortened, and the static error and fluctuation are greatly reduced. As the result, the photovoltaic loads can be well protected and the utilization ratio of the solar energy is improved. In this paper simulations are presented in both changing and fixed environments, and the superiority of the variable universe fuzzy control in MPPT is proved from the points of output power and load voltage.