Algorithms to estimate the temperature and effective irradiance level over a photovoltaic module using the fixed point theorem

Abstract

The purpose of this paper is to present four algorithms to calculate the effective irradiance level, E <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</inf> and temperature, T, of operation for a photovoltaic module, PVM. The main reasons to develop these algorithms are for monitoring climate conditions, the elimination of temperature and solar irradiance sensors, reductions in cost for a photovoltaic inverter system, and development of new algorithms to be integrated with maximum power point tracking algorithms. The first three algorithms use only the short circuit current, open circuit voltage, the operating current and voltage for the PVM, avoiding the use of pyranometers and thermocouples. The last algorithm can estimate the irradiance level using only the open circuit voltage and the PVM temperature of operation. Finally, simulations and experimental results are presented in the paper.