热电制冷LED自然对流散热的设计与优化

Thermal Design and Optimization of LED Integrated with Thermoelectric Cooler in Natural Convection

为提升高热流密度下LED灯具的自然对流散热性能,以一款基于热电制冷(TEC)的单颗LED小型灯具模组为研究对象,在采用实验测量和回归拟合准确获得TEC性能参数的基础上,建立了有无TEC参与散热的等效热路模型,并选择合理的数学公式对其进行性能描述,进而遵循本文设计的计算流程快速得到各种散热性能数据。LED模组的散热分析表明:在恒定的LED热功率下,施加最佳的TEC电流可获得最高的散热性能;LED热功率越低,安装TEC的散热性能越比常规方法优异。经遗传算法优化前后的性能对比分析表明:优化后结构中TEC的合理工作区明显增大,能满足LED更高功率的散热需求;当LED为0.493 W时,优化后结构的最佳结温仅为15.66℃,远低于30℃的环境温度。基于TEC实验数据建立的等效热路模型,能为装配TEC的LED模组提供快速完整的散热设计分析与结构优化的合理方案。

In order to improve the thermal performance of LED lamp with high heat flux in natural convection,a thermoelectric cooler(TEC)was presented to meet the cooling requirement of a compact lamp with single high-power LED.The performance parameters of TEC were determined accurately by regression analysis for TEC experimental data at different work status.The equivalent thermal circuits of the compact LED modules with TEC and without TEC were established based on electrical-thermal analogy.Some mathematic models of equivalent thermal circuits were developed to quickly predict the accurate thermal performance of LED modules following the specified calculation procedure in this paper.The thermal performance analysis results show that the best cooling performance can be obtained at the optimum input TEC current for a specific LED power dissipation.The thermal performance of LED modules with TEC can be superior to that of modules without TEC and be better at low LED power dissipations than at high ones.Two-objective optimization was carried out using three design variables of fin to minimize the junction temperature and fin mass simultaneously.For the un-optimized and optimized modules,the comparison results of thermal performance demonstrate that the effective operating range of TEC in optimized module performs broader than that in un-optimized module.The LED power dissipation of optimized module can reach a higher performance than that of un-optimized one.At the LED power dissipation of 0.493 W,the minimum junction temperature is 15.66℃and much lower than the ambient temperature of 30℃.For the LED modules with TEC,the equivalent thermal circuit models presented based on TEC experimental data can contribute to the thermal design,performance analysis and structural optimization.