Revisiting multi-domain empirical modelling of light-emitting diode luminaire

In this work, an empirically derived multi-domain model of a light-emitting diode (LED) luminaire is proposed. The optical, electrical, and thermal characteristics of LEDs are obtained from the data sheets provided by manufacturers. Both transient and steady-state performance of LED luminaire were realized theoretically and validated against experimental findings from earlier investigations. The difficulties encountered in creating an ideal LED luminaire are discoursed and examined. Most of the studies on LED luminaires described in prior works ignored the influence of luminaire housing and optics on the thermal management of the luminaire. Knowledge of thermal time constants of LED luminaires is important, as they decide the rate of luminous flux decay when LED lighting systems are used for long periods of operation. Thermal time constants also decide the time taken by the LED junction to reach steady state with its surrounding. From the study it is inferred that the increase in junction temperature and deterioration of luminous flux is controlled by the product of the single most dominant thermal resistance from the junction to a point along the heat conduction path and sum of all the downstream thermal capacitances. This is true as in most cases LED device thermal capacitance is very less related to the thermal capacitance of the heat-sink, hence the product of single most dominant thermal resistance and thermal capacitance of heat-sink decide the rate of rising of junction temperature or luminous flux deterioration.