The Electromotive Force Dependence on the Polycrystalline Silicon Solar Cell Illuminance

The impact of illuminance on changes of the solar cell electromotive force is analyzed. A mathematical model for a solar cell electromotive force dependence on illuminance is presented. For this purpose, a selection of experimental data trend function was carried out, and the Pearson correlation coefficients were established. The most optimal results were obtained in case of an exponential function with the strongest correlation ($R^2$=0.983). The analysis has shown that at 100 W/m^2 illuminance the electromotive force saturation is obtained (the electromotive force changes insignificantly and fluctuates at around 2 V), which indicates that upon reaching such an illuminance a solar cell operates at maximum efficiency. A first-order differential equation satisfied by the trend function has been compiled. When interpreting illuminance as an evolution variable, the proposed mathematical model can be interpreted as a dynamical system. The deviation frequency spectrum of the measurement values with respect to the theoretical prediction is analyzed.