光伏发电最大功率跟踪的非对称模糊控制

受外界环境影响,光伏电池系统的输出特性呈现非对称的强非线性,输出功率常常偏离最大输出功率点(MPP)。为提高光电能量转换效率,在分析P O机理的基础上,采用扰动观察法(P O)跟踪光伏电池MPP；针对P O缺点,在MPP两侧采用不同的隶属度函数和模糊控制规则,提出了一种非对称模糊控制算法,并使用Matlab中的Fuzzy工具箱对模糊控制器进行了设计。基于所搭建的Matlab/Simulink仿真模型,对比分析了在环境变化时P O法和非对称模糊控制法的最大功率点跟踪曲线。仿真结果表明,所提方法提高了MPP跟踪的动稳态性能,在外界环境变化时更能有效、快速、准确的实现最大功率点跟踪。

Asymmetric fuzzy control of MPPT for photovoltaic system

The output characteristics of photovoltaic cell system become asymmetric along with strong nonlinear, and the output power of system always deviates from the maximum power point(MPP) as the external environment change. By analyzing the mechanism and structure of perturb and observe (P O) method, the P O method was used to track the MPP of PV to improve the efficiency of photoelectric energy conversion. Aiming at the shortcomings of P O, the asymmetric fuzzy control strategy was proposed with employing different membership functions and fuzzy control rules at both sides of the MPP, the fuzzy controller was designed by the fuzzy toolbox of the matlab software. Based on the established Matlab/Simulink simulation model, the MPPT curves both of the P O method and the asymmetric fuzzy control method were compared and analyzed when the external environment changed. The simulation results showed that the proposed method improved the dynamic and steady state performance of MPPT and can more efficiently, quickly and accurately track the MPP in any the external environment.