A combined two-method MPPT control scheme for grid-connected photovoltaic systems

In order to increase the output efficiency of a grid-connected photovoltaic (PV) system it is important to have an efficient maximum power point tracker (MPPT). In the case of low irradiation, the perturb and observe (PO) and incremental conductance (IC) methods have a poor efficiency, because of the poor resolution in the acquired signals, when a fixed point implementation is done. A cost-effective two-method MPPT control scheme is proposed in this paper to track the maximum power point (MPP) at both low and high irradiation, by combining a constant voltage (CV) method and a modified PO algorithm. Simulation and experimental results are presented to verify the performance of the proposed method.