Analysis of solar panel’s lumped equivalent circuit parameters using LASSO

The power output of a solar panel depends on the level of degradation and external factors, such as temperature and solar irradiation. The changes in the power output caused by temperature and irradiation fluctuations coincide with the changes due to degradation. Therefore, a common way of degradation determination requires the knowledge of external factors. This work investigates a modeling of the panel power output at the reference state without the knowledge of the external factors. Firstly, a sparse regression modeling is used to identify relevant lumped equivalent circuit parameters, which capture the reference state of the solar panel. The p-n junction capacitance is found to be an important indicator of external factors tied to the panel's state of health. Secondly, a set of regression models for modelling the solar panel reference state are tested to distinguish a permanent 5% drop in power output from a regular temperature and irradiation fluctuations, without the information of the temperature and irradiation.