Extremum Seeking Control-based Global Maximum Power Point Tracking algorithm for PV array under partial shading conditions

The aim of this paper is to present a general description about the method called Extremum Seeking Control (ESC), and its applications in the nonlinear systems, which have an unknown dynamics. The system we are interested in is the photovoltaic system. This technique presents a solution on real time optimization control problems. When a photovoltaic panel is exposed to the same irradiation range, the power-voltage characteristic has a single maximum point. However if a portion is shaded or covered by the clouds, this characteristic will have several maximum points. Hence in the first case, it is possible to track the maximum by a conventional maximum power point tracking (MPPT) method but in the second case a simple MPPT may fall into the local MPP (LMPP), that why ESC algorithm is implemented (to track global MPP). The Photovoltaic panel is modeled and the ESC algorithm is designed using Matlab/Simulink Software.