A generalised approach for the estimation of junction temperature and its effect on light output

Abstract

LED lighting is the most promising lighting technology of the current era because it is highly reliable and energy efficient. The reliability of an LED luminaire is dependent primarily on its junction temperature in operation. Since LED luminaire design differs across manufacturers, a generalised experimental procedure and simplified model is adapted to estimate the junction temperature of an LED luminaire. The results are analysed, and the model is validated with an experimental study on two different luminaires. Further, to analyse the effect of junction temperature on the light output, a novel model and methodology are adopted such that light output can be estimated for any operating temperature, if the light output at a reference temperature is known. Three models were selected to estimate the light output at different temperatures, and four different LEDs were selected for the experimental study. A linear model for the thermal multiplier is selected as the best model to estimate the light output at a desired temperature and is validated using statistical tools. Thus, this simple model and generalised experimental procedures will help in estimating the effect of junction temperature on the performance of LED luminaires.