Lifetime analysis of led driver under different operating conditions

In this thesis, lifetime evaluation of outdoor LED luminaires were analyzed under different operating (serial and parallel LED connection, etc.) and environmental conditions (wind speed, ambient temperature, vb.). LEDs, optical lens, heatsink and LED drivers are the fundamental components of LED luminaires. Luminaires' life generally depends on LEDs and LED drivers. Although LEDs have a long lifetime when compared to other conventional light sources, this life time can vary depending on LED drivers. For this reason, while analyzing lifetime of LED luminaires, it is necessary to consider not only LEDs but also LEDs drivers that are the essential part of these systems. The maximum lifetime in datasheets are given by manufacturer under certain conditions. Because these conditions can differ in practice, lifetime analysis should be carried out considering operating and environmental conditions for more realistic results. The proposed semiconductor switch model and lifetime analysis method in this thesis are based on finite element analysis (FEA) which uses the actual material properties and dimensions. A novel approach which study electrical, thermal and mechanical performances of LED drivers under different operating conditions and environmental conditions is presented in this thesis. The electrical and thermal performance of both LED and LED driver's semiconductor switch and capacitor under high and low driving voltages have been investigated taking into account the LED connections in series and parallel. Besides, the actual ambient temperature, wind speed and lighting times of two different climatic conditions are taken into account, and the electrical, thermal and mechanical performance of the designed LED driver semiconductor switch has been investigated and the semiconductor switch lifetime of the LED driver has been obtained considering material properties under different operating and environmental conditions. In addition, LED connection used in LED luminaire have been found to affect the system both electrically and thermally. The parallel connection of the LEDs provides an advantage in terms of safety and cost, while the serial connection provides reduced power losses and homogeneous temperature distribution. In two different locations with different climatic conditions, LED drive life is different. As a result, the proposed approach is feasible in different areas. The experimental setup, electronic circuits and software developed in this thesis can be used both undergraduate and graduate level studies. This thesis on LED driver lifetimes can be considered as an original content especially contributing to the Turkish literature.