Multi-diode modeling of multi-junction solar cells

Abstract

This paper introduces a new model for gallium arsenide (GaAs) solar cells. GaAs technology plays an important role in the high efficiency solar cells industry. GaAs solar cells are fabricated in single-junction and multi-junction structures. The one that we study here is the mathematical model and electrical equivalent circuit of multi-junction solar cell, which is compared with the model of commercial single layer Silicon (Si) cells. Subsequently the modeling and simulation of a triple-junction cell is discussed and a new equivalent circuit model is proposed for triple-junction solar cells. We evaluate these models in various environmental conditions, cell specifications and physical dimensions. We consider three main factors: maximum power, short circuit current density and open circuit voltage of the solar cell. Taking into account the overall effect of temperature and solar irradiance, the proposed models are evaluated, and the resulted simulation data are presented. Results indicate that the proposed model accurately represent the cell operation in real conditions.