Improved fitting model for the incidence angle modifier of photovoltaic modules with textured glass and/or coloration

The angular dependency of optical losses in PV superstrates is commonly described using the incidence angle modifier (IAM). Most common IAM models, foremost the Martin&Ruiz model, are unable to accurately fit the IAM of PV modules with coloration and/or textured glass surfaces. In this work, a comparison of common IAM fitting models is carried out for samples with colored interlayers, ceramic printing on glass, and samples with various textured glass surfaces.To improve IAM fitting, a modification of the Martin&Ruiz model through the addition of an absorptive term based on Beer-Lambert’s law is introduced. In addition, a possible compensation term for light scattering from textured surfaces is presented. In combination, these terms can significantly improve IAM fitting accuracy for all samples.