The Research On Maximum Power Point Tracking In Photovoltaic Generation System Based On Fuzzy PID Control

Recent years, the research of maximum power point tracking control has becomea hot problem in photovoltaic generation system. Scholars propose a variety of MPPTcontrol method, Traditional control methods include constant voltage method, perturband observe method, incremental conductance method and fuzzy logic method and soon. Constant voltage method is simple, easy to implement, but this tracking approachignores the influence of temperature on open circuit voltage of the solar PV array.Perturb and observe method and incremental conductance method have precise controland faster response speed, etc. But they have relatively high hardware requirementsand high system cost. The fuzzy control method is used in nonlinear systems.Aiming at the shortcomings of existing methods, this paper analyzes the outputcharacteristics of the photovoltaic arrays. As the photovoltaic array has characteristicssuch as non-linear，time-varying and can not establish a precise mathematical model.The traditional Fuzzy controller and PID controller can not satisfy the requests ofhigh-performance control，such as accurate speed or torque control and robustness.This paper proposes the fuzzy-PID control to maximum power point tracking controland achieves MPPT function by boost circuit.The composition and classification of photovoltaic generation system has beendescribed in this paper. Operating characteristics of photovoltaic array and realizationof boost circuit in photovoltaic generation system are also analyzed. Finally the basicprinciple of several controllers for fuzzy control in the maximum power point trackingis introduced. Simulation has been carried out on Matlab/Simulink, on which a PIDcontroller, a fuzzy controller and fuzzy PID controller model have been build for PVsystems.The simulation results show the fuzzy PID can not only quickly respond tochanges in the external environment，which can effectively eliminate the work of themaximum power point of the oscillation in fuzzy controll and also make upshortcomings of a longer transition time. It guarantees that system work in themaximum power point and improve the efficiency of the system.