Paper Title
Enhancement of P&O Algorithm for MPPT for Partially Shading PV Systems

Abstract
During Partial shading of photovoltaic (PV) modules, the PV arrays receives a different amount of irradiations, this may be caused by passing clouds, tree shadows, bird droppings, dust and neighboring buildings. Maximum power point tracking (MPPT) using Perturbation and Observation (P&O) method is a common and efficient technique which is used to operate the PV system with its highest efficiency. The downside of P&O MPPT methods is its fluctuation around the maximum power point and this will decrease the PV panel efficiency. To overcome this drawback different modifications for the P&O MPPT method has been presented. This research proposed a variable step size P&O MPPT method for enhancing the PV system performance by fast tracking for the maximum power point of the PV panel during partial shading conditions. A dc-dc buck converter is used to step down the output voltage of the PV array. The controller is used to adjust the duty cycle of the converter so that the model will operate at the maximum power of the PV array. This method is faster than the conventional P&O and has lower oscillation around the MPP. Keywords - Photovoltaic Panel, Buck Converter, Maximum Power Point Tracking (MPPT), Perturbation and Observation (P&O) algorithm.