Variance in the solar spectrum with the position of the receiver surface during the day for PV applications

A study of the annual and daily variation in the spectral distribution of the solar irradiance and its influence on PV devices is presented. This study was performed by means of a spectral correction parameter, F which indicates the ratio between the short-circuit current (I_sc) under spectral standard conditions and the measured I_sc under actual spectral conditions. Test results show that F varies daily and annually in a different way for m-Si and a-Si PV devices. It is also shown that the interval of time during the day in which the spectral correction to measured I_sc is not higher than 2% is considerably reduced from summer to winter months