Modeling improvement of the four parameter model for photovoltaic modules

The aim of the present work is to introduce some improvements on the four parameter model of the photovoltaic cells in order to fit the variation of the current voltage characteristic I-V under various operating conditions. That is achieved by modifying both the open voltage equation and the voltage at the maximum power point, in order to take into consideration the effects of the variation of the equivalent circuit parameters with irradiation and temperature. The accuracy of this model is verified by using seven PV modules of different types (mono-crystalline, multi-crystalline, and thin-film) from various manufacturers and compared with the five parameter and the two diode models, where it gives the same or better performances. Moreover, it is motivated by the known simplicity of the four parameter model and the small amount of input data requested which can make it as a valuable tool for PV power converter designers and circuit simulator developers.