A Modified Perturb and Observe MPPT for a Fast and Accurate Tracking of MPP Under Varying Weather Conditions
Rafah Ibraheem Jabbar, Saad Mekhilef, Marizan Mubin, Karam Khairullah Mohammed
Abstract
Photovoltaic (PV) systems provide a reliable green energy solution by improving maximum power point tracking (MPPT) methods to achieve maximum power under various weather conditions. Among MPPT algorithms, the perturbation and observation (P&O) algorithm is widely used in PV systems due to its simple implementation. However, the algorithm has limitations in terms of tracking convergence speed, steady-state oscillation, and drift problem during sudden irradiance variations. This paper proposes a modified P&O algorithm for optimal MPPT under different weather conditions. A new strategy is used to control the duty cycle perturbation step size, which provides faster tracking convergence. The algorithm detects the attainment of the steady-state oscillation in a simple way and then stops the perturbation process. This eliminates the oscillation around the MPP. Moreover, the algorithm can detect the change in solar irradiance immediately and solve the drift problem without additional sensors. The proposed method was simulated using MATLAB/Simulink and then validated experimentally under different irradiances utilizing a boost converter with a 0.05 s sampling time. The experimental results showed that the proposed strategy could be successfully implemented, with an average tracking time of 0.5 s and an average steady-state efficiency of 99.8%. Moreover, the results showed that the proposed method was superior to the standard P&O algorithm, with a 50% improvement in tracking time. In this study, a real-time test was conducted to verify the effectiveness of the proposed algorithm under different solar irradiances and temperatures.