Implicit Approximation of Photovoltaic Panel Characteristics Using a Stochastic Approach

In this article, an original system is described for an implicit approximation of photovoltaic panel characteristics. Photovoltaic panels (PV panel) are considered stochastic systems. Long-term measured basic characteristics are input data of the system. Each measurement is one of the stochastic PV realizations. Basic 2-D PV characteristics are approximated using implicit circle equations. Calculated circle passes through the three chosen points of a so-called stochastic cloud and it is an quasi-average PV model. The described approximation system includes all of practice influences over the PV, e.g. solar irradiation, temperature, PV wear, random events, etc. An original 3-D implicit final approximation is also introduced. The mentioned method is unambiguous and it also enables the user to intervene. The method is strictly based on measured data and it was developed and verified in MATLAB environment.