Control and stabilization of three-phase grid connected photovoltaics using PID-Fuzzy logic

The aims of this paper are to propose an intelligent hybrid control based in two methods of maximum power point tracking (MPPT) using fuzzy logic and classical PID controllers of a photovoltaic system under variable temperature and irradiance conditions, to improve the dynamic response, the efficiency and the stability of single stage three-phase photovoltaic grid-connected inverter. The combination of the intelligent fuzzy logic with the classical PID controller makes the control of nonlinear characteristic of photovoltaic array more feasible. The proposed intelligent hybrid PID-Fuzzy logic controller automatically varies the coefficients Kp, Ki and Kd under variable temperature and irradiation, load change and uses directly the DC-DC converter duty cycle as a control parameter. Finally, the new method gives a good MPPT operation ot any photovoltaic array under different conditions such as changing solar radiation and PV cell temperature. The simulation results and the comparison of results obtained separately from PID controller and hybrid proposed intelligent controller of PID-Fuzzy logic show the advantages of the proposed intelligent algorithm in terms of correctness and the feasibility, overshooting and stability and maintains its response better than the PID controller in many aspects.