Improving Accuracy of Solar Cells Parameters Extraction by Minimum Root Mean Square Error

Abstract

This paper presents a technique for enhancing the accuracy of parameters extraction of photovoltaic (PV) cells from experimental current-voltage (I-V) curve. This technique is based on entering nearly all the possible points of an I-V curve to extract the slopes near the open circuit voltage and short circuit current to determine approximate values of the series and shunt resistance, respectively. These values are utilised to find accurate values of the five parameters of the single diode model based on an analytical method from the literature. The calculated I-V curves from all groups of points are then compared with the experimental one and the curve that provides the minimum root mean square error (RMSE) is selected as the best fit. Experimental results are provided in this paper to validate the approach. The results show that the analytical method can become more accurate than iterative/numerical methods if the points used to calculate the slopes are properly selected.