Ten-thousand-hour LM-80 test data for various LEDs are used for model development. In this paper, Kalman filter (KF) and extended Kalman Filters (EKF) have been used to develop a 70% Lumen Maintenance Life Prediction Model for LEDs used in SSL luminaires. The correlation of lumen maintenance with underlying physics of degradation at system level is needed. The underlying TM-21 model may not capture the failure physics in presence of multiple failure mechanisms. Several failure mechanisms may be active in a LED at a single time, causing lumen depreciation. Currently, the TM-21 test standard is used to predict the L70 life of LEDs from LM-80 test data. The LEDs continually degrade, and the light output decreases eventually below useful levels causing failure. However, the LEDs have no filament to “burn“. For an incandescent bulb, the lamp life more » is defined by B50 life. Traditional light sources “burn out” at the end of life. This makes it important to increase our understanding of what effects high temperature exposure for a prolonged period of time will have on the usability and survivability of these devices. They are also being used in outdoor applications in desert environments that see little or no humidity but will experience extremely high temperatures during the day. Solid-state lighting (SSL) luminaires containing light-emitting diodes (LEDs) have the potential of seeing excessive temperatures when being transported across country or being stored in nonclimate controlled warehouses. Life prediction of L70 life for the LEDs used in SSL luminaires from KF and EKF based models have been compared with the TM-21 model predictions and experimental data. The measured state variable has been related to the underlying damage using physics-based models. The future state of the lumen depreciation has been estimated based on a second order Kalman Filter model and a Bayesian Framework. System state at each future time has been computed based on the state space at preceding time step, system dynamics matrix, control vector, control matrix, measurement matrix, measured vector, process noise and measurement noise. Ten-thousand hour LM-80 test data for various LEDs have been used for model development. In this paper, Kalman Filter (KF) and Extended Kalman Filters (EKF) more » have been used to develop a 70-percent Lumen Maintenance Life Prediction Model for LEDs used in SSL luminaires. Correlation of lumen maintenance with underlying physics of degradation at system-level is needed. The underlying TM-21 Model may not capture the failure physics in presence of multiple failure mechanisms. Several failure mechanisms may be active in a LED at a single time causing lumen depreciation. Presently, the TM-21 test standard is used to predict the L70 life of LEDs from LM-80 test data. The LEDs continually degrade and the light output decreases eventually below useful levels causing failure. However, the LEDs have no filament to “burn”. For an incandescent bulb, the lamp life is defined by B50 life. Traditional light sources “burn out” at end-of-life. Solid-state lighting (SSL) luminaires containing light emitting diodes (LEDs) have the potential of seeing excessive temperatures when being transported across country or being stored in non-climate controlled warehouses.
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