Evaluation of numerical algorithms used in extracting the parameters of a single-diode photovoltaic model

The current-voltage relationship of the single-diode photovoltaic (PV) cell/panel equivalent circuit model is defined by its implicit nonlinear transcendental equation, which is difficult to solve using analytical methods. This difficulty has led to the development of several algorithms for solving this equation using numerical techniques. This paper investigates and compares three different algorithms commonly employed in solving current-voltage equation of a 5-parameter single-diode solar PV model using manufacturer's data sheet. The comparison is performed based on accuracy (i.e. closeness of the obtained results to experimental values), required computer memory, speed of computation, robustness of the algorithm, and ease of implementation of algorithm. The results reveal that no single algorithm performs best in all the metrics and there will always be a trade-off in the choice of the algorithms based on the user's focus. Villalva algorithm is preferable in terms of robustness whilst T. Esram performs better in the area of computational speed, memory space and ease of implementation. No generic conclusion could be easily made in terms of accuracy as it varies with the PV technology and parameter of interest. The present work can be a potential tool for researchers and designers working in the area of photovoltaic systems, to make decisions related to the selection of the best possible algorithm for the extraction of the characteristic parameters of single-diode 5-parameter PV models. (C) 2015 Elsevier Ltd. All rights reserved.