Analytical model of light current-voltage characteristics of a solar cell based on experimental data

Abstract

In this work, a modified experimental method for calculating the parameters of the one-exponential equation of the light current-voltage characteristic of solar cells has been developed using approximation and verification of experimental data. This approach allowed us to create a more accurate mathematical model of such characteristics. It has been confirmed that the approximation equation of the open circuit voltage versus short circuit current contains the necessary data to establish the numerical values of the p-n junction parameters: the imperfection factor and the saturation current of the one-exponential model of the light current-voltage characteristics of a solar cell. A comparison between the experimentally measured results and those predicted by the mathematical model results allowed not only to correctly determine the values of the parameters of the one-exponential equation of light current-voltage characteristics, but also to identify instrumental and computational errors in the experimental studies. An expression for calculating the series resistance based on verified current and voltage values at the point of maximum power was derived. In cases where the current or voltage values at the maximum power point are questionable, the determination of the series resistance value is possible using numerical methods for solving the equation of the single-exponential model in a narrow range of the light current-voltage characteristic curve in the vicinity of the maximum power point. The use of algorithms in maximum power point tracking systems that more reliably determine its coordinates increases the efficiency of these systems and the output power delivered to the load.