The MPPT control of PV system using the series-connected PI controller

This paper proposes the series-connect PI control for MPPT control of photovoltaic 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 series-connect PI controller that is adjusted input value of the second PI controller by first PI controller, and the maximum power point tracks using this controller. The validity of the controller proposed in this paper proves through the results of the comparisons.