基于变步长与非对称模糊的光伏MPPT控制策略

Photovoltaic MPPT Control Strategy Based on Variable Step Size and Asymmetric Fuzzy

针对于光伏发电系统的输出特性,容易受到外界变数的影响而出现非对称的强非线性特征,输出的功率会偏离最大输出功率点的现象。分析了最大功率点跟踪的几种常用控制策略的优缺点,对P-U曲线进行了分析,提出了非对称模糊与变步长电导增量法相结合的控制策略。这里的变步长电导增量法可以在远离最大功率点两侧时,快速靠近最大功率点,当进一步靠近最大功率点区间附近时,采取非对称模糊控制进行寻优,能够较好地削弱系统在最大功率点周围的振荡现象,提升整个系统的稳定性能。通过MATLAB/Simulink进行建模仿真对比,得出所提的方法有较好的动态性能。

In view of the output characteristics of photovoltaic power generation system,it was vulnerable to the influence of external variables and presents asymmetric strong nonlinearity,and the output power often deviates from the maximum output power point. Here we discuss the advantages and disadvantages of several commonly used maximum power point tracking control method,the P-U curve was analyzed,and puts forward the method of asymmetric fuzzy and variable step incremental conductance method combining the variable step incremental conductance method here can be far away from the maximum power point on both sides,fast approaching the maximum power point. When further near the maximum power point near the interval,at this time,the asymmetric fuzzy control optimization,could effectively eliminate the oscillation phenomenon in the vicinity of the maximum power point,improve the stability of the system. The simulation results in MATLAB/Simulink showed that the proposed method had better dynamic performance.