A MODIFIED PERTURB AND OBSERVE ALGORITHM FOR MAXIMUM POWER POINT TRACKING OF PHOTOVOLTAIC SYSTEM USING BUCK-BOOST CONVERTER

Abstract

Perturb and Observe (P&O) maximum power point tracking (MPPT) algorithm is widely applieddue to its simplicity, costless and easy implementation. However, P&O tracking algorithm suffersfrom drift or instabilities due to change of irradiance, and oscillation around maximum power point(MPP) at steady state. Drift occurs due to the incorrect decision taken by the conventional P&Oalgorithm at the first step change in duty cycle during the change in irradiance. This paper modifiesconventional P&O algorithm to overcome these drawbacks and improve MPPT performance ofphotovoltaic (PV) system and DC/DC converter to supply a resistive load under rapidly change ofweather conditions. This modified technique is proposed to avoid the problem of irradiancevariation by incorporating the information of voltage, current and power in the decision process forupdating the duty cycle of the converter. Simulation results of the proposed algorithm achievedminimum power oscillations with high accuracy, better dynamic response and stability for changesof irradiance, load and temperature. The obtained results are compared with the previousexperimental results which are obtained in the literature.