A Modified Global Maximum Power Point Tracking Algorithm for a Partially Shaded Photovoltaic System

In this work, a global maximum power point tracking algorithm is proposed to ensure maximum power is extracted from a photovoltaic system under partial shading conditions by utilizing a modified perturb and observe algorithm. Unlike standard perturb and observe algorithm with constant reference voltage, a dynamic reference voltage is employed. An initial reference voltage is first found by sweeping the characteristic curve of photovoltaic system, and then the maximum power point is located by perturbing from a voltage close to but less than the reference voltage. The partial shading conditions in this work are implemented into a photovoltaic system using data sets from National Renewable Energy Laboratory. The simulation studies are conducted to evaluate the performance of the proposed strategy.