Numerical determination of series and shunt resistances using the Lambert W-function

Abstract

A number of methods currently exist to determine the values of series and shunt resistance of a solar cell which are generally unpublished and necessary for modeling of photovoltaic systems. A new method is proposed to numerically locate these values using the popular Newton-Raphson technique at maximum power point from data predominantly provided by manufacturer data sheets. Equations based on the Lambert W-function and their partial derivatives are provided so that all calculations can be performed in a Matlab or similar environment. The results of this new method are presented and compared with one current method and the analytical results obtained by Charles et al. [1] for a blue and grey type solar cells which were selected based on their largely varying characteristics. Values determined with the proposed method agreed with benchmark results in all cases and with greater accuracy over the alternative method studied. Additionally, values for both series and shunt resistance were determined quickly with quadratic convergence.