| LED has been widely used in lighting field since high bright blue LED was invented last nineties.However,the application is focusing on special lighting and is still not popular in general lighting due to its cost and thermal management.As the development of technology,the efficacy of LED will be improved and its cost will reduce,but the thermal problem is still a bottle-neck which baffles LED's application in general lighting.Consequently it makes great sense to the whole LED industry that we carry on research on LED thermal model-building and thermal management.The thesis is based on LED thermal problem and it includes mainly:1,We consider the LED thermal problem to be a thermal control system and build its thermal model to describe its dynamic state response,and analyze the model using the theory tool on control system.2,We summarize the kind of heatsink using in LED luminaire and analyze thermal efficiency of the most popular heatsink.Then several luminaires were used to calculate theoretically and measure real junction temperatures,results were compared to check the reasonability of the thermal model.3,We design a LED tunnel lamp,then test its optic parameters and junction temperature in natural work state.Then we test the attenuation of the LED tunnel lamp's light output.According to the data tested in 16 months,we estimate the life of the lamp.4,To improve the test method of junction temperature via forward voltage,we introduce a new method which uses big driving current(350mA) compared to traditional small driving current(10mA).We choose 4 samples from different manufacturers and measure the junction temperature with our method and the conventional method.By analyzing the results,we prove that the method introduced in this paper is reasonable。... |
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