Research On Heat Dissipation And Response Surface Optimization Design Of High Power Integrated Package White LED

As a new generation of electrical light source, Light Emitting Diode (LED) possessessuch advantages as high luminous efficiency, low power consumption, long life time, shortresponse time, wide color temperature range, being eco-friendly and etc. At present, it hasbeen used in many applications, including general lighting, landscape lighting, stagelighting, automotive lighting, traffic signal, backlight, display, indicator, flash function forcamera and etc. It will play an important role in many fields, such as health care,information, agriculture, aviation, aerospace and etc. To make LED be large-scale used insome special occasions such as airport and stadium, the luminous flux must be thousandsof lumens, high power integrated package white LED can be designed to meet such a highluminous flux. However, heat dissipation problem is still the main bottleneck constrainingits development. For the heat dissipation problem of a100W high power integratedpackage white LED, the following researches were launched.On the basis of some typical thermal management methods of high power LED,according to the characteristics of high power integrated package white LED, a novelthermal management method of Vapor Chamber Printed Circuit Board (VCPCB) combinedwith sunflower heat sink was presented. VCPCB is a substrate that replaces metal core ofMetal Core Printed Circuit Board (MCPCB) with vapor chamber. Sunflower heat sink is astructure that dissipates the heat effectively from heat source to top and surrounding.Secondary development of Mechanical APDL (ANSYS) was conducted usingANSYS Parametric Design Language (APDL) and User Interface Design Language(UIDL). A thermal analysis module was embedded into the ANSYS Main Menu. Thermalperformance of the100W high power integrated package white LED based on VCPCBcoupled with sunflower heat sink was investigated using the module. And a comparisonwas made with thermal analysis results of LED based on MCPCB coupled with sunflowerheat sink.In order to extend the lifetime of LED and further achieve the purpose of energysaving and emission reduction, when LED is operating, on the premise of guaranteeing theLED luminous flux, choosing proper drive current is very essential. In this thesis, opticaland thermal characteristics tests of a1W InGaN/GaN white LED sample were conductedto reveal the effect of LED drive current on luminous flux, luminous efficiency andjunction temperature.Caculation process of ANSYS was integrated into optimization software OPTIMUS.Response surface optimization design of the100W high power integrated package white LED based on VCPCB combined with sunflower heat sink were conducted usingOPTIMUS. Design of Experiment (DOE) of Box-Behnken method was adopted, leastsquare Response Surface Model (RSM) based on second-order Taylor polynominal wasused to fit the sample points of DOE and optimization algorithm of Non-linearProgramming by Quadratic Lagrangian (NLPQL) was used to find the optimal heatdissipation structure of the LED.Research results showed that: firstly, compared with MCPCB, VCPCB improveduniform temperature performance of high power integrated package white LED chips andavoided local hot spots, thereby improved its reliability and ensured its lifetime. Secondly,for the1W LED sample, the drive current of about315mA was reasonable. At the drivecurrent, the luminous flux could be guaranteed, the luminous efficiency was higher, and thejunction temperature was lower. For the100W high power integrated package white LED,on the premise of guaranteeing the illumination requirement, choosing proper drive currentis very essential. It could significantly extend the effective lifetime of LED and furtherachieve the purpose of energy saving and emission reduction. Thirdly, the height ofsunflower heat sink was main design parameter. When the length of VCPCB was60mm,the vapor thickness of VCPCB was1mm, the fin thickness of sunflower heat sink was1.5mm and the height of sunflower heat sink was60mm, LED junction temperature was thelowest, and was56.3°C.The results of the thesis will provide a practical thermal management method for highpower integrated package white LED, and provide a theoretical basis and technical supportfor further heat dissipation research and optimization design of high power LED.