A Complete Numerical Investigation on Implicit and Explicit PV Single-Diode-Models Using I- and V-Approaches

The single-diode-model (SDM) is widely used for the identification of a photovoltaic (PV) module output curve. However, the implicit nature of the model imposes a few difficulties such as need for an iterative solution method, high computation load and large computation time. In the last years, several mathematical approximations have been adopted in order to convert the implicit SDM into explicit one. In turn, this simplicity has invited other complications: inaccuracy in the curve identification, wrong maximum power point computation, additional parameters over the (five) SDM parameters etc. This article considers the complete and comprehensive comparisons of all possible ways (numerical methods) to compute the output curve. This article provides clear guidelines to the researchers in PV modeling and helps to select an appropriate numerical method. The SDM computation is carried out by the I-approach and V-approach using all possible methods. All methods are tested on cells and modules in uniform irradiance conditions, four commonly used case studies in PV literature. Also, the investigation is extended for two more case studies that include a PV string and a PV array operating under partial shading conditions. In summary, this article supplies a useful PV modeling manual that provides freedom to select a suitable method based on the I- or V-approach equations, the convergence criteria and the computation execution burdens. Overall, the work proposes the series expansion of Lambert-W in both approaches is the most suitable method for PV curves computation.