Maximum Power Point Tracking of the PV Array under Partial Shading Condition

Abstract

Photovoltaic technology has been playing an important role as a clean source of energy. However, electrical power from a PV system can be varying depending on local weather conditions, i.e., irradiation and temperature. Therefore a maximum power point tracking (MPPT) method is needed to consistently generate maximum power from the PV system. Many MPPT algorithms had been proposed. Perturb & Observe and Incremental Conductance methods are most commonly used in practice. PV arrays are subject to partial shading in many practical situations due to nearby trees, buildings and PV panels. Multiple peaks can exist on the resulting P-V curve of the PV array under partial shading conditions. This may disturb the efficient MPPT operation as conventional MPPT methods can converge to local peaks. In this paper, effects of different shading conditions on the characteristics of the PV array have been investigated. Based on the results and observations, a simple MPPT technique is proposed to circumvent the trappings into the local peaks. Effectiveness of the proposed method has been verified by computer simulations.