Experimental design to study the performance of a solar cell at high altitude

Abstract

This bachelor thesis is focused on the previous theoretical and experimental study of an array of four monocrystalline solar cells that are going to be implemented on a high altitude balloon. The balloon will carry the cells through the troposphere and part of the stratosphere. It covers the theoretical background of solar energy, with a detailed explanation on how electricity is generated using photovoltaic cells and the factors that modify the radiation while passing through the layers of the Earth atmosphere. An experimental design has been performed in order to be able to measure voltage and current of solar cells on the balloon and to characterize the cells, by obtaining the curves of current versus voltage, the power and the changes in open circuit voltage and short circuit current with temperature and radiation. The characteristic I-V and power curves have been compared to the ideal ones, obtained with the implementation of the correlations between voltage and current in a Matlab script. Furthermore, a theoretical approach of the insulation of the cells has been made, as the temperature gradient decreases with altitude and affects the performance of the solar cells. Also, the changes in radiation have been studied in order to decide whether the implementation of filters are necessary for protecting the cells from excessive levels of radiations. All the experiments have been carried out by developing a code with Arduino and Matlab softwares.