On the Thermo-Electrical Modeling of Small Satellite's Solar Panels

The thermal modeling of small satellites (up to 100 kg) is crucial for predicting and managing their operation, and may present significant differences when compared to the thermal modeling carried out in relation to larger spacecraft. In this article, the modeling of their solar panels is underlined as one of these differences. The efficiency of spacecraft solar panels is affected by three main variables: the sun's irradiance, the cells' temperatures, and the operating voltage. Unlike the most common approach, which only takes into account the first two variables and decouples the thermal problem from the electrical one, the coupled thermo-electric problem of the solar panel efficiency as a whole is considered in this article. Using the UPMSat-2 mission as an example, the importance of considering the operating voltage in the thermal analysis of a mission is proven in the present article (for the prediction of temperature and generated power). A simple but accurate I-V (Current-Voltage) curve model to calculate panel efficiency is proposed for modeling the solar panels performance, this method being easily implemented in ESATAN^©.