Effects of series and shunt resistances on the performance of PV panel under temperature variations

The photovoltaic (PV) array performance is significantly affected by solar irradiation, temperature and its configuration. Indeed, the array configuration has an impact to modify the series (Rs) and the shunt (Rsh) resistances that appear in its mathematical model. Moreover these resistances are dependent on temperature variation. Hence, the latter can affect I-V and P-V characteristics by modifying the Rs and Rsh resistances. Consequently, the maximum power point (MPP) can be shifted and thus the efficiency and reliability of the entire PV system can be affected. This paper is based on modeling and simulation of the I-V and P-V characteristics of a PV array under non uniform temperature that influences the series and shunt resistances. Simulation results show that, compared to the case when temperature variation do not affect the Rs and Rsh resistances, temperature variation effect is always dominated and the resistances effects are more visible for high temperature value. However the comparison Rs and Rsh effects shows that the Rs variation effect versus temperature variation is more significant. The proposed PV array study can be used in PV system design and it permits to evaluate its performance not only under standard conditions but also under resistances variations. Indeed, it is very important to predict the PV array behavior to an effective use of a PV system under all conditions.