Original Research Article Evaluation of numerical algorithms used in extracting the parameters of a single-diode photovoltaic model T.R. Ayodele, A.S.O. Ogunjuyigbe ⇑ , E.E. Ekoh Power, Energy, Machines and Drives (PEMD) Research Group, Electrical and Electronic Engineering Department, Faculty of Technology, University of Ibadan, Nigeria article info Article history: Received 14 March 2015 Revised 13 August 2015 Accepted 13 November 2015 Keywords: Comparison Numerical algorithms Single-diode model Solar PV Datasheet values abstract 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. Ó 2015 Elsevier Ltd. All rights reserved. Introduction The need to increase the security of energy supply, mitigate environmental pollution and foster job opportunities through the emerging new green technologies in recent years has made clean and renewable energy sources an inevitable option of consideration. There are various types of renewable energy sources with different associated conversion technologies. However, the substantial increase of research and development work in the area of photovoltaic (PV) systems has made the PV one of the fastest growing renewable energy technologies for electricity generation around the world [1]. This increasing attention can be attributed to the ubiquity of the sun, non-polluting nature of photovoltaic systems, increasing efficiency of solar cells, improvements of manufacturing technology of solar panels [2] and the eventual economic long-term benefit for island (stand-alone) and intercon- nected power systems. Although PV systems are excellent for clean sustainable power generation, their electrical output varies as a function of ambient environmental conditions (temperature of the photovoltaic cell, the level of solar irradiance) and the operating voltage of the con- nected load [3,4]. This poses a major drawback in PV system design, since the connected load must operate at the point where maximum power is derived from the PV generators. To achieve the maximum power point operation of a PV system, the changing environmental parameters vis-à-vis the characteristic of PV gener- ators must be adequately matched. Outdoor testing of all commer- cially available PV modules at different operating conditions in order to obtain their characteristic behaviour is costly, time con- suming [5] and really not feasible considering the amount of mod- ules currently available in the market. To surmount this challenge, researchers have developed various mathematical models to understand and predict the effect of these changing conditions on PV electrical output. Amongst these models, the lumped param- eter electric circuit based models have proven to be more success- ful and as a result are widely applied in literature [6]. There are different lumped parameter models which are classified based on the number of diodes [7]. They are single diode model, double diode model [8] and in recent times the three diode http://dx.doi.org/10.1016/j.seta.2015.11.003 2213-1388/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +234 8023504826 E-mail addresses: tr.ayodele@ui.edu.ng (T.R. Ayodele), a.ogunjuyigbe@ui.edu.ng, aogunjuyigbe@yahoo.com (A.S.O. Ogunjuyigbe), elstonekoh8@gmail.com (E.E. Ekoh). Sustainable Energy Technologies and Assessments 13 (2016) 51–59 Contents lists available at ScienceDirect Sustainable Energy Technologies and Assessments journal homepage: www.elsevier.com/locate/seta