An advanced high performance maximum power point tracking technique for photovoltaic systems

Abstract

The key requirements for the control of the photovoltaic (PV) energy conversion systems are to achieve very fast yet quite accurate tracking of the maximum power point under rapidly changing environmental conditions and to obtain efficient unperturbed tracking operation under steady environmental conditions. In this work, a high-performance Maximum Power Point Tracking (MPPT) technique, based on existing Incremental Conductance method, is proposed to meet these challenging requirements. In the proposed MPPT technique, a new function for adaptive variable step-size is defined using the conductance of the PV arrays. Using this adaptive variable step-size, the proposed method can track the Maximum Power Point (MPP) in a very rapid manner, and hence, can achieve much faster dynamic response than the conventional MPPT methods. Further, an adaptive tolerance band is introduced to define the MPP condition. The proposed tolerance band is utilized to obtain highly accurate and oscillation free efficient MPPT operation under all the operating conditions; including low level insolation condition, under which the conventional methods fails to perform efficient operations. Analysis, simulation, and experimental results, carried out on a micro-grid based PV energy conversion system, are presented for the validation of the proposed technique.