Numerical modeling and experimental validation of the electrical characteristics of a photovoltaic panel

Photovoltaic cells are conversion systems that transform the photons from the sun into electrical energy through their semiconductor layers. In the equivalent circuit equation of a photovoltaic cell, several numerical and analytical models have been developed to estimate parameters such as the light current (Iₚₕ), parallel shunt resistance (Rₛₕ), series resistance (Rₛ), modified diode factor (a), and reverse saturation current (Iₒ). This study proposes a new numerical method called the "Improved Five-Parameter Model" developed in MATLAB for solving the equivalent circuit equation. Using this model, the unknown parameters of a panel are calculated numerically based on only the technical information provided by the manufacturer. The results from the MATLAB calculations are compared with the existing "Five-Parameter Model" and experimental data of a 36-cell polycrystalline photovoltaic panel under different operating conditions, using statistical methods such as RMSE and R-Square. Furthermore, a numerical approach using the Generalized Reduced Gradient (GRG) numerical method is applied to solve the model, and the unknown parameters of a 48-cell polycrystalline panel are calculated. The results show that the newly developed model, using only the technical data from the panel label, provides more accurate results compared to other methods.