A maximum power point tracking method for PV system with improved gravitational search algorithm

Abstract

Photovoltaic (PV) system has gradually become research focus in the field of renewable energy power generation, and the output efficiency of PV system is the major concern of researchers. There are obvious non-linear characteristics in the output of PV system, and it will be greatly affected by external environment. For achieving the maximum output power, PV system must operate under the guidance of maximum power point tracking (MPPT) methods The tracking time and accuracy of these methods need to be improved. Therefore, this study contributes to increase output efficiency of PV system by improving the tracking time and accuracy of existing MPPT methods Specifically, a MPPT method with improved gravitational search algorithm (IGSA-MPPT) was proposed. The dynamic weight was added in the change factor of the gravity constant and the related factors of memory and population information exchange were added into the updating formula of particle velocity. IGSA-MPPT not only reduced the tracking time, but also improved the tracking accuracy and mitigated the fluctuations of the reference voltage. Finally, simulation results are compared with the of MPPT methods with particle swarm Optimization (PSO-MPPT) and gravitational search algorithm (GSA-MPPT). The average tracking time of IGSA-MPPT was reduced by 0.023 s and 0.0116s, and the average increase rates of maximum power were increased by 1.7071% and 0.7001% compared with PSO-MPPT and GSA-MPPT. In the simulations of PV system under the varying irradiance and temperature, the tracking speed and tracking accuracy of IGSA-MPPT were higher than those of PSO-MPPT, GSA-MPPT, GWO-MPPT, ICO-MPPT, and FCGSA-MPPT. In summary, IGSA-MPPT has better performance in tracking time and accuracy than other comparison algorithms. It can improve output efficiency of PV system in practical application.