Retrofitting the Translation Equations of the One-Diode Model for Photovoltaic Modules

One of the most common approaches to estimate the photovoltaic parameters under varying environmental conditions is to first extract these parameters at a reference condition, usually at standard test conditions (STC). The temperature and irradiance dependance of each of these STC parameters is then calculated using a set of translation equations. Although the translation equations are based on device physics, the biggest disadvantage of this approach is that the constants in the translation equations are not universal for different photovoltaic technologies. To address this limitation, a unified fitting approach has been proposed, which not only extracts the five photovoltaic parameters but also adjusts the constants of the translation equations. The proposed method exhibits a marked improvement in the fitting accuracy for the measured I-V curves of the module.