Variation of solar irradiances on the value of seven parameters of two-diode model plays an important role in a photovoltaic (PV) modules performance to develop design and fabrication of PV modules. This paper proposes a novel modeling approach for amorphous silicon thin film PV module to determine the effect of solar irradiance change on seven parameters of two-diode model and to describe the I-V characteristic curves for each generic condition of operative solar irradiance. The proposed model is based on the rate change of seven parameters with respect to irradiance change. The rate change of seven parameters is derived from current equation of two-diode model at maximum power point (MPP) of different solar irradiance levels. The values of the parameters of the two-diode model are extracted with respect to different solar irradiance levels using precise Runge-Kutta-Merson iterative method. To validate the capability of the new proposed method, the new proposed method is verified on three different amorphous silicon and thin film PV modules, U-EA110, MPV95-S, and MST-43LV, for various I-V and P-V manufacturer curves. Results are compared with the data issued by different manufacturers. The I-V and P-V curves of manufacturing three different amorphous and thin film PV modules have a good agreement as compared with computed results of proposed model. (C) 2016 Elsevier Ltd. All rights reserved.