A variable step-size P&O method in the application of MPPT control for a PV system

At Maximum power point tracking for photovoltaic power generation system technology, this paper explains the principles of photovoltaic power generation and the establishment of mathematical models. Combined with solar photovoltaic array output characteristics and principle of traditional P&O method, analyses of oscillation and misjudgment issues in P&O method are done. Improved variable step P&O method is proposed, which solves effectively the conflicts between tracking speed and the steady-state tracking accuracy in traditional fixed step P&O method, and improves tracking speed to avoid misjudgment and oscillations in the search for maximum power point. Traditional and improved P&O methods are respectively emulated by PV simulation model builded by MATLAB/Simulink, simulation and experimental results show that the proposed method is effective.