A Photovoltaic MPPT Control Strategy Based on Gradient Optimization and MPP Voltage Law

In this work, a maximum power point tracking (MPPT) control algorithm is developed to determine power efficiency, and to improve the transient nature of the power curve characteristics of a PV cell. Based on the analysis of existing MPPT methods, for PV systems, the relationship between MPP voltage and the open circuit voltage of PV cell under different conditions is studied; moreover, a novel MPPT control strategy which can be applied to different irradiance conditions based on a sub-domain gradient optimization principle and MPP voltage law is proposed. Simulation results show that the proposed method has advantages of fast dynamic response and a non-oscillatory steady state response under different irradiance conditions and input waveforms. For the experimental setup, an existing control method and the proposed MPPT control algorithm are implemented on solar PV cell; it was observed that the proposed MPPT algorithm has stable steady state dynamic characteristics and a fast response speed.