An enhanced MPPT algorithm based on adaptive extremum-seeking control applied to photovoltaic systems operating under partial shading

This study presents an improved extremum-seeking control (ESC) method, intended to optimise the maximum power point tracking (MPPT) in a photovoltaic (PV) generation system. More specifically, to overcome the problem associated with partial shading in PV systems that leads to multiple operating points, an adaptive loop based on the measured PV array power is added to the conventional ESC. This procedure creates a variable amplitude of the perturbation signal and is able to accurately reach and track the global maximum power point (GMPP). The perturbation signal amplitude changes only when a predetermined power variation value is exceeded. As a result, this MPPT algorithm provides an efficient extraction of solar energy, avoids large oscillations in output response, and ensures the proper operation and performance of the system. The ESC theory is described in detail and the feasibility and effectiveness of the proposed approach are proved through simulation and experimental results. Furthermore, comparative tests show the proposed method's performance improvement, compared to the conventional ESC, evaluated in terms of convergence time, power oscillation in steady state, and accuracy to track the GMPP.