Adaptive multi-variable step size P&O MPPT for high tracking-speed and accuracy

Abstract

Improvement of the output power under different weather conditions is one of the major concerns for photovoltaic (PV) system design. The perturbation and observation (P&O) maximum power point tracking (MPPT) algorithm is the most commonly used technique in practice due to its simplicity and ease of implementation in low-cost hardware. However, the conventional fixed-step P&O tracking method uses a fixed iteration step size based on the requirements of the steady - state accuracy and the speed of the algorithm. In addition, it is very hard to specify the variable step-size scaling factor (M) under fast ripped change of insolation. This paper presents an adaptative multi-variable step-size to solve the trade-off between the speed of the algorithm and efficiency at steady-state. Computer simulation is carried out on MATLAB/Simulink to validate the performance of the proposed algorithm. By using multi-variable step-size algorithm, MPPT response speed and accuracy can be significantly enhanced under rapid change of irradiance compared to one scaling variable step-size P&O method.