Numerical calculation of series and shunt resistance of a photovoltaic cell using the Lambert W-function: Experimental evaluation

Abstract

The values of series and shunt resistances play an important role in the modelling behaviour of a photovoltaic cell. The authors proposed in earlier work a new method to determine these values numerically at maximum power point using the Newton-Raphson method and equations based on the Lambert W-function. Here, an experimental investigation has been carried out to further validate this method and observe its behaviour over the entire current voltage curve. Current voltage curves from a single multi-crystalline cell were obtained under outdoor testing in Hamilton, New Zealand under three levels of illumination (800, 900, and 1000 W/m(2)). In addition to the method of Ghani and Duke (2011), two other methods were also used to calculate series and shunt resistances based on the parameters extracted from the experimental data. A comparative study of each methods output current vector using a root mean square error analysis revealed that greatest accuracy was achieved with the proposed approach.