A Modified Perturb and Observe MPPT for a Fast and Accurate Tracking of MPP Under Varying Weather Conditions

Abstract

Photovoltaic (PV) systems provide a reliable green energy solution by improving the maximum power point tracking (MPPT) methods to achieve maximum power under various weather conditions. Among the MPPT algorithms, the perturb and observe (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 was used to control the duty-cycle perturbation step size, which resulted in a faster tracking convergence. The algorithm detects the attainment of steady-state oscillations in a simple way and then stops the perturbation process. This eliminates the oscillation around the MPP. Moreover, the algorithm can immediately detect the change in solar irradiance and solve the drift problem without additional sensors. The proposed method was simulated using MATLAB/Simulink and validated experimentally under different irradiances using 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 the tracking time. In this study, a real-time test was conducted to verify the effectiveness of the proposed algorithm for different solar irradiances and temperatures.

Keywords

• Maximum power point tracking
• perturb and observe
• variable step size
• steady-state oscillation