MPPT control of photovoltaic system using FLC-PI controller

This paper proposes the fuzzy - PI controller for maximum power point tracking(MPPT) control of photovoltaic system. The output characteristics of the solar cell are a nonlinear and affected by a temperature, the solar radiation and influence of a shadow. The MPPT control is a very important technique in order to increase an output and efficiency of the photo voltaic system. The conventional constant voltage(CV), perturbation and observation(PO) and incremental conductance(IC) are the method which finding maximum power point(MPP) by the continued self-excitation vibration, and uses the fixed step size. If the fixed step size is a large, the tracking speed of maximum power point is faster, but the tracking accuracy in the steady state is decreased. On the contrary, when the fixed step size is a small, the tracking accuracy is increased and the tracking speed is slower. Therefore, in order to solve these problems, this paper proposes FLC-PI controller. The PI controller of FLC-PI controller is compensated for cumulative error of fuzzy control and fuzzy control adjusts the input value of PI controller. The validity of the controller proposed in this paper proves through the results of the comparisons.