Metaheuristics Assisted Efficiency Maximizing Flexible Power Point Tracking of a Photovoltaic Array Under the Partial Shading

Abstract

The vast installation of the photovoltaic (PV) plants has necessitated bringing more flexibility to the PV power generation instead of the simple maximum power point tracking (MPPT). Certain flexible power point tracking (FPPT) techniques have already emerged to operate the PV array not only at the maximum power point (MPP) but also below the MPP. Similarly to the MPPT, the FPPT also needs special control techniques to operate under the partial shading condition. Apart from the local peak blockage problem, there is an issue of solution multiplicity in the FPPT. As there may be multiple equilibrium points for a specific power level, a procedure is needed to dynamically select the equilibrium at the highest voltage level so that the thermal stress on semiconductor devices can be minimized by maximizing the power conversion efficiency. The present work is undertaken to meet the particular objective. A metaheuristics assisted efficiency maximizing (MAEM) control algorithm is suggested to attain the desired power regulation under partial shading. A specific implementation of the MAEM control is shown for a two-stage PV system with due consideration for the duty ratio quantization effect. The proposed MAEM-FPPT control technique is thoroughly verified via both MATLAB simulations and practical experimentation.