Three-state Variable Step Perturbation Observation MPPT Algorithm Based on Power Prediction

Abstract

In view of the application and research status of maximum power point tracking technology in photovoltaic power generation system, an improved disturbance observation MPPT method with variable step size and no oscillation at steady state is proposed in this paper. The method combines power prediction disturbance method and constant voltage method. Firstly, two reasons for power loss caused by traditional disturbance observation method are analyzed, which are disturbance misjudgment and steady state oscillation respectively. In order to reduce power loss caused by disturbance misjudgment and steady state oscillation, the three-point function sampling model based on Newton interpolation method is used to reduce disturbance misjudgment respectively, and a new variable step size factor is proposed to realize fast tracking of maximum power point through variable step size. And when the steady state is reached, the disturbance step size is immediately reduced to achieve a small shock output, so as to improve the efficiency of the whole system. Finally, the photovoltaic system model and experimental platform are built to track and simulate the maximum power point. The results show that the improved disturbance observation method can not only improve the disturbance misjudgment, but also achieve stable tracking of the maximum power point.