An Improved P&O Method MPPT Control Strategy Based on Model Predictive Control for PV System

Aiming at the problems of the traditional P&O method can't guarantee the dynamic performance and steady-state accuracy at the same time when the external environment changes, for PV system, an improved P&O method maximum power point tracking (MPPT) control strategy based on model predictive control is proposed in this paper. Firstly, the motion of PV operating point is divided into forward motion and reverse motion, and based on this, the perturbing step is divided into large and small step sizes. The forward motion corresponds to small step and the reverse motion corresponds to large step, so as to reduce the oscillation of the PV at the maximum power point (MPP) and increase the dynamic performance and robustness of the PV system for external environmental changes. Secondly, by analyzing, it can be known that the impact of solar irradiance on PV output power is much greater than that on PV output voltage and current. Therefore, the changing value of PV output power is used to judge whether solar irradiance change occurs, and if there is a change for the solar irradiance, the reference current will be modified, further more to improve the dynamic performance and robustness of the PV system. Finally, the method proposed in this paper is compared with the conventional P&O control with fixed, variable and adaptive step sizes to verify the feasibility and effectiveness of it.