New analytical expressions of photovoltaic solar module physical parameters: Effects of module temperature and incident solar irradiance

Abstract

In this work, we present three methods to extract model physical parameters of a photovoltaic solar module modelled by a single-diode electronic circuit. The model physical parameters we are looking for are photocurrent Iph , saturation current Is , ideality factor η, series resistance Rs and shunt conductance Gp . The first method is based on exact solution of module characteristic equation, the second one uses exact expression of dynamic conductance and the third one makes use of exact expression of the integral of translated current-voltage characteristics (I-Isc ). In all these extraction methods, we achieve numerical fitting of experimental data of output current, differential conductance and area under translated characteristics with suitable analytical expressions to get model physical parameters at standard test conditions (STC). Then, we assume these values as initial conditions and derive exact analytical expressions reporting effects of module temperature and incident solar irradiance on photocurrent, saturation current and ideality factor using temperature coefficients provided as well as irradiance coefficients extracted from module manufacturer datasheet. We examine new analytical expressions of model physical parameters in the case of Shell SQ80 photovoltaic solar module at arbitrary operating conditions of module temperature and solar irradiance. We evidence good agreement between experimental characteristics and forecasted analytical characteristics generated by new analytical expressions.

A Compact Mathematical Modelling for Performance Evaluation of PV Module considering Single-Diode M odel

“…The proposed model is simple, compact and closed form, whereas the ref (18) mode l is based on an iterative method that is time-consuming. The numerically calculated results of equation 1(c) show an excellent matching with ref (19) results for V<V oc and a slight difference for larger terminal voltage is due to negligence of material properties in the proposed model (Figure 6 (b)). The values of parameters of R s , R sh , I ph , I 0 and η, taken from different published papers, are given in Table 3 .…”

“…The values of parameters of R s , R sh , I ph , I 0 and η, taken from different published papers, are given in Table 3 . (20) 0.1617 573.51 1.663469 1.5100579 1.58333 STM-120/36 (20) 0.17585 360.22 7.4836 1.20897 1.2367 Photowatt-PWP201 (20) KC200GT (18) Shell SQ 80 PV (19) Figure 7 compares I-V characteristics obtained using the proposed mathematical model with experimental findings of various PV modules as reported in the ref (20) . Our numerically calculated values show an excellent matching with the experimental values, except at higher terminal voltages due to negligence of temperature effect in the model that drastically affect the performance of the module.…”

“…Figure 5 shows that beyond the critical value of V oc , photocurrent remains constant irrespective of I sc . To show the validity of the proposed closed form current-voltage equation (which is derived using minimal approximation), we have compared the numerically calculated value of current at various terminal voltage for the KC200GT with ref (18) (Figure 6 (a)) and the Shell SQ80 PV modules with (19) results (Figure 6 (b)). The proposed model shows an excellent matching with (18) results.…”