A Granular Modeling Method For Non-Uniform Panel Degradation Based On I-V Characterization And Electroluminescence Imaging

A new model of photovoltaic (PV) panel is proposed. The model precisely replicates sub-cell level degradation, such as cracks and interconnect failures, and reproduces their effect at the panel level I-V characteristic. Moreover, a regression method is proposed, which infers the model's parameters from combination of electroluminescent (EL) image and degraded I-V characteristic. The combination of quantitative (EL image) and qualitative (I-V characteristic) enables to characterize the degradation of the cells embedded in the PV panel, without physical access to the cells. The proposed model and the regression problem is experimentally verified on a set of 3 single cell measurements and a set of 4 crystalline PV panels with various levels of degradation.