双模糊控制法在光伏并网发电系统MPPT中的应用

Application of double fuzzy control in MPPT of grid-connected photovoltaic generation system

提出一种在光伏并网发电系统中进行最大功率点跟踪(MPPT)的双模糊控制法,将非对称模糊MPPT与模糊PID相结合,在设定参考电压环节使用模糊控制代替诸如扰动观察法等传统方法,在消除实际电压与参考电压偏差这一环节用模糊PID替换普通的PID控制。此外,还提出了4个反映MPPT性能的指标:环境缓慢变化时的MPPT时间、光伏阵列发出的能量大小、稳态时的功率波动大小和环境剧烈变化时光伏阵列发出的能量大小。设计了4个算例,在MATLAB/Simulink环境下对5种控制方法分别进行了仿真分析。通过对比各方法的性能指标和相应的输出功率波形图,验证了所提出的双模糊控制法是一种比传统方法更优的MPPT控制方法。

The double fuzzy control is proposed for the MPPT（Maximum Power Point Tracking） of grid- connected photovoltaic generation system,which combines asymmetric fuzzy MPPT and fuzzy PID together. The conventional method such as perturbation-observation is replaced by the asymmetric fuzzy control in the reference voltage setting section and the general PID control is replaced by the fuzzy PID control in the actual-reference voltage deviation elimination section. Four MPPT performance indexes are proposed： tracing time when environment changes slowly, power output of photovohaic array, steady-state power fluctuation,and power output of photovohaic array when environment changes greatly. Four cases are designed and five control methods are respectively simulated in the environment of MATLAB/Simulink. The comparison of the indexes of MPPT performance and the waveform of output power verifies that,the proposed double fuzzy control method is better than the traditional methods.