A new model-based technique for fast and accurate tracking of global maximum power point in photovoltaic arrays under partial shading conditions

Abstract

This paper presents a new model-based method to extract the global maximum power point (GMPP) of photovoltaic (PV) arrays under partial shading conditions (PSCs). In the proposed method, it is shown that independent of the pattern and intensity of the solar radiation, the position of the PV array GMPP voltage is always in the neighboring of one of the strings GMPP voltages in the PV array. Therefore, the number of local peak points tested in the proposed method is independent of the solar radiation pattern and is equal to the number of parallel strings in the PV array. As a result, for tracking of PV array GMPP in the PSCs, at first, the GMPP of each of PV strings is estimated. Next, by the numerical solution of the PV string nonlinear equations, the PV array output current and power are calculated corresponding to each of PV string GMPP voltages, and the voltage that results in the highest PV array output power is detected as the PV array GMPP voltage. Numerical results and comparative studies with similar methods confirm the satisfactory operation of the proposed technique.