N IMPROVED VARIABLE STEP SIZE MPPT METHOD FOR PHOTOVOLTAIC ARRAY UNDER PARTIAL SHADING CONDITIONS

Abstract

Photovoltaic (PV) systems are prone to partial shading effects, which cause multi-peak power points on the output curve, named local maximum power point (LMPP). The traditional perturbation and observation (P&O) algorithm will search into it when tracking maximum power. This paper proposes an improved variable step size (IVSS) perturbation tracking method to reduce the impact of perturbation step size choice on dynamic PV performance. MATLAB/Simulink software is used to develop and simulate the improved maximum power point tracking (MPPT) system. The IVSS tracking algorithm uses a program to achieve step perturbation. Finally, simulation results of the traditional P&O algorithm are compared with those achieved using the MPPT, verifying the superiority of proposed method in terms of tracking time, steady-state accuracy and maximum output power.