Determination of Photovoltaic Characteristics in Real Field Conditions

This paper presents an improved procedure in the modeling of photovoltaic (PV) modules based on the single-diode model. This improvement allows more accurate energy yield predictions and performance analysis. Variation of parameters of the PV module model is taken into account, since the output characteristics depend on the surrounding conditions. The analytical expressions of the single-diode model along with experimental data are utilized to support the modeling approach. Moreover, the spectral effects, which influence the output of PV modules, are included in the model. Hence, the PV characteristics in real outdoor operating conditions could be precisely predicted. The effectiveness of the proposed procedure was tested against experimental measurements taken in a PV installation with different commercially available PV modules. The PV model was also validated using real data collected by the SCADA system of a 12-MW PV farm. A comparison with previous methods was made to show the advantages of the proposed model. This model can provide a powerful tool for analysis and appropriate selection of PV systems under changing environmental conditions.