大功率发光二极管的热管理及其散热设计

Thermal Management and Heat Dissipation Design for High-power LEDs

对大功率发光二极管的散热路径及其相应的热阻进行了分析和计算。利用商业计算流体力学软件对大功率发光二极管进行热流分析及散热优化设计。理论计算结果表明,PN结到环境之间的总热阻为28.67℃/W;当LED耗散功率为1 W、环境温度为25℃时,结温为53.67℃。模拟结果显示,在同样工作条件下,大功率发光二极管的结温为54.85℃,与理论计算结果相吻合。当散热面积达到一定值时,散热效果基本不变。因此,从降低产品成本出发,散热器的面积有一限值范围。当散热器的鳍片垂直向左时,空气流体流向上无阻碍,其散热效果最好,结温最低。

Thermal path and the corresponding thermal resistance of high - power LED is analyzed and calculated. The heat flow analysis and heat dissipation optimal design of high - power LED is realized by using commercial computational fluid dynamics （CFD） software. Theoretical calculation result shows that the total thermal resistance of high - power LED from the junction to the ambient is 28.67 ℃/W. When the dissipated power is 1 W and the ambient temperature is 25 ℃, the junction temperature of high - power LED is 53.67℃. Simulation result shows that on the same working conditions the junction tem- perature of high - power LED is 54.85 ℃. It is good agreement with the theoretical calculation results. The results show that when the area of heat dissipation increases to a certain value, the heat dissipation effect remains a constant. Thus,considering the lower product costs, the area of heat sink has a threshold range. When the heat sink is installed for the vertical fins to the left, the air - fluid flow on unimpeded, the heat dissipation has the best effect,and the junction temperature of high - power LED is lowest.