Combined analytical and numerical approach to determine the four parameters of the photovoltaic cells models

The main contribution of this work is to propose an efficient and accurate method for identifying and determining the values of equivalent circuit elements of photovoltaic module using only exact analytical equations and four manufacture´s data reference, i.e., the open-circuit voltage (V_OC), the short-circuit current (I_SC) and the current and the voltage at the maximum power point (I_M, V_M). All used equations were obtained with a transparent analytical procedure. To avoid using any mathematical simplifications or other physical assumptions when extracting R_S (series resistance) parameter, a fast and accurate iterative numerical method is proposed. For determine a four or five PV parameters model, many authors proposed several procedures that require the entire experimental I-V curves or based on many estimations, assumptions and simplifications for solving non-linear I-V equations. These techniques lead to a PV parameters model with a minimum error. We apply this combined method in order to extract the four-parameter Single-Diode models of photovoltaic modules. The effectiveness of this approach is evaluated and validated by Matlab/Simulink environment, through comparison of simulation results of the model to the data provided by product´s manufacturer. It envisaged that this work is very useful for PV power electronics designers who require exact, fast and accurate approach for modeling emulating their photovoltaic modules under various environmental conditions.