An Efficient Tracking of MPP in PV Systems Using a Newly-Formulated P&O-MPPT Method Under Varying Irradiation Levels

Abstract

This paper proposes a newly-formulated Perturb and Observe (P&O) method for Maximum Power Point Tracking (MPPT) in PV systems. The new formulation considers the effect of solar irradiation level on tracking the maximum power point (MPP). The formulated P&O method is tested under standard test condition (STC) to achieve tracking efficiency 99.98% against 98.4% for the conventional P&O method, 99.5% for the improved and 99.85 for the adaptive versions of the P&O method irrespective of the location of the initial operating point to the right or left of the MPP. The higher the tracking efficiency, the closer is the operation of the PV module to the MPP with a subsequent capture of maximum electric energy available in the incident solar radiation. At constant irradiation level, the tracking efficiency reaches 99.98% for the formulated method against 98.4% for the conventional P&O and 83.6–98.5% for the improved and adaptive versions. The amplitude of output power oscillations around the MPP is reduced to 0.05% of its average value for the formulated method against 1.02% for the conventional P&O, 0.5% for the improved and 0.8% for the adaptive versions. Also, the smaller the oscillations’ amplitude, the closer is the operating point to the MPP. The proposed formulation of P&O tracks successfully the MPP under various conditions including the Ropp irradiation profile, step and ramp changes of irradiation level. However, the conventional P&O method fails to track the MPP under Ropp and ramp changes of irradiation level.