Physics-based electrical modelling of CIGS thin-film photovoltaic modules for system-level energy yield simulations

Copper indium gallium selenide(CIGS)is a commercialized,high-efficiency thin-film photovoltaic(PV)technology.The state-of-theart energy yield models for this technology have a significant normalized root mean square error(nRMSE)on power estimation:De Soto model—26.7%;PVsyst model—12%.In this work,we propose a physics-based electrical model for CIGS technology which can be used for system-level energy yield simulations by people across the PV value chain.The model was developed by considering models of significant electrical current pathways from literature and adapting it for the system-level simulation.We improved it further by incorporating temperature and irradiance dependence of parameters through characterisation at various operating conditions.We also devised a module level,non-destructive characterization strategy based on readily available measurement equipment to obtain the model parameters.The model was validated using the measurements from multiple commercial modules and has a significantly lower power estimation nRMSE of 1.2%.