A two subcell equivalent solar cell model for III–V triple junction solar cells under spectrum and temperature variations

•Obtain Pmpp of MJ solar cells under temperature and spectral changes are essential.•This allows understanding and predicting the behaviour of MJ solar cells.•The aim of this paper is to define a simple way to obtain Pmpp.•A model based on two equivalent solar cells is introduced.•The model predicts Pmpp of a LM triple junction solar cell at one sun condition. While single junction solar cells are mainly influenced by changes in irradiance and temperature, multi junction concentrator solar cells show complex behaviour as their performance is also strongly influenced by changes in spectrum. Despite this, when studying the system, it is possible to reduce the problem to a set of parameters that could easily be measured and fitted. A simple model to obtain the maximum power point of multi junction solar cells under temperature and spectral changes is proposed. This model is based on a single diode model and is described by a simple set of equations that are easy to fit within a computational program. The model could be useful to understand the behaviour of multi junction solar cells and also CPV technology under real conditions. The main purpose of this paper is to define a simple way to estimate the maximum power point of a multi junction solar cell under spectral and temperature changes at one sun conditions.