Selecting a suitable model for characterizing photovoltaic devices

The aim of this work is to evaluate a simple analytical method for extracting parameters involved in the photovoltaic module behaviour equation. Based on a series of experimental voltage-intensity curves obtained under various temperature and irradiance conditions, values are obtained to extract the model parameters, giving rise to adjustment errors at data points (short circuit current, open circuit voltage and voltage at maximum power point) and in the entire curve that are less than 1%. It has also been confirmed that assigning suitable values for series and parallel resistance avoids having to know beforehand the slope value of the characteristic curve, which is not normally indicated in the solar module specifications; this gives rise to good adjustment results between the experimental curves and the theoretical model, even when the theoretical parameters are adapted to other temperature and irradiance conditions. (C) 2001 Elsevier Science Ltd. All rights reserved.