Electrical modeling of CIGS thin-film solar cells working in natural conditions

In the paper, results of electrical modeling of Cu(InxGa1−x)Se2 (CIGS) thin-film photovoltaic (PV) modules are presented. Whether the equivalent double diode model—DEM (Double diode Equivalent Model) is appropriate to model CIGS PV modules was investigated. Modeling was based on large amount of data (including current–voltage (I–V) curves) collected during long-term outdoor monitoring of PV systems. The process of applying baseline physical parameters to two of five DEM parameters: diffusion IS1 and recombination IS2 related components of dark diode saturation current was carried out. Modeled IS1 and IS2 values were used to replace previously approximated DEM parameters and then to predict measured I–V curves in order to determine electrical parameters of the PV modules. The parameters are used to predict energy yield in natural operating conditions. Results of modeling are presented and compared with measured data.

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► Checking the applicability of two equivalent electrical models: SEM and DEM for electrical modeling of CIGS thin-film solar cells.
► Using data collected during long-term outdoor exposure.
► Deriving the equations for the diffusion and recombination related components of dark diode saturation current with the module temperature dependence.
► Double diode model (DEM) is assures better accuracy of fitting thin-film PV modules' light I-V curves than single diode model (SEM).