Subcell Modelling of Partially Shaded Solar Photovoltaic Panels

Increased installation of PV panels in residential areas has resulted in rising incidents of partial shading, where a part of the solar photovoltaic panel is shaded. This not only reduces the output but can also cause deteriorating hot spots on the shaded panels. To understand the phenomenon of partial shading, a detailed model including subcell level behaviour analyses the output of PV panels under different kinds of shading patterns with varying ambient conditions. In addition a method to include the effect of background diffused light is proposed. Four methods for analytically estimating shaded system output are compared, where the proposed subcell based method is shown to give least error when compared with the experimental measurements. It is shown that the proposed modelling approach improves the output prediction accuracy by 5-10% as compared to the average insolation based modelling approaches.