A Two-Stage Tracking Algorithm for PV Systems Subjected to Partial Shading Conditions

Abstract

This paper proposes a golden section search (GSS) based global peak power tracking (GMPPT) algorithm to track the global peak of the PV array under partial shaded conditions. Partial shading is a common scenario in building integrated PV systems where shading is cast by clouds, birds, nearby structures, trees, etc. The conventional MPPT algorithms fail to track the maximum power as, under partially shaded conditions, multiple peaks characterize the voltage-power curve. These algorithms oscillate around the first peak they detect resulting in lower harvest efficiency. Sophisticated algorithms that can detect the global peak are necessary under such conditions and many multi stage tracking algorithms have been proposed in the literature. This paper proposes a new two stage GMPPT algorithm that can track the maximum power under all irradiation conditions. The first stage of the algorithm shrinks the search interval in the neighborhood of the global peak and the second stage detects it. The reliability of the algorithm is tested for various partial shaded conditions and the simulated outcomes presented exemplify the effectiveness of the proposed GSS based GMPPT algorithm.