An improved Perturb and Observe Maximum Power Point Tracking Algorithm with the capability of drift avoidance in PV systems

Photovoltaic (PV) systems have become important as they are an environmentally friendly energy source. Maximum Power Point Tracking (MPPT) algorithms are used to improve PV system efficiency. The Perturb and Observe (P&O) algorithm is the most widely used of the MPPT algorithms. The conventional P&O algorithm suffers from drift when the irradiance increases. This occurs when the conventional P&O algorithmic controller is unable to correctly decide the tracking direction due to a change in irradiance. An improved P&O MPPT algorithm is implemented in this paper and its strength is tested for a number of irradiance changes. The improved P&O algorithm is able to more effectively surmount the problem of drift by employing an extra check on the current change before deciding the tracking direction and implementing a variable step size in doing so. Simulations were done with MATLAB/Simulink comparing the conventional and improved P&O algorithms. The results show that the improved P&O was better at avoiding drift.