Mathematical model for determining the performance characteristics of multi-crystalline photovoltaic modules

Mathematical models for predicting the performance characteristics of multi-crystalline photovoltaic (PV) modules have been developed. In any prediction of the electric output of PV systems, an understanding of its characteristics is of fundamental importance. These characteristics are popularly expressed in the form of IV curves that may be presented graphically; or using equations. There exists many equations for calculating the photogenerated current IL, saturated current I0 and a fitting-parameter a. The characteristics of PV modules using simulations and experiments on multi-crystalline modules have been conducted. To achieve this, an experimental PV system of 5 kWp capacity was set-up comprising of 40 modules, arranged in a string combination of 8 in series by 5 in parallel. The current and voltage data were recorded at various solar radiation levels and module temperatures. This paper then presents and discusses a set of new equations pertaining to a, IL, I0, and the maximum power point. These results were expressed using graphs and equations with constant values and compared with those obtained from the experimental set-up. This set of equations could be used to predict performances and maximum power points of a PV module using temperature and solar radiation data only.