针对一款阵列型大功率LED投光灯的散热特点, 建立了关键散热结构的物理模型, 并基于等效热路法选用能正确表达其热传导和热对流性能的数学模型, 进而遵循本文设计的计算流程能快速计算出自然对流边界条件下的散热性能。通过与红外热像仪的实测温度进行比较, 发现二者数据吻合性好, 误差仅为+1.08%。随后经散热器关键结构参数对散热性能的影响趋势分析可以看出: 肋片间距对投光灯模型存在明显的最优选择, 宜采用5 mm的肋片间距; 增加肋片高度和减薄肋片厚度均能提升模型的散热性能, 但建议须同时考虑减重、成本和可加工性, 以获取更适宜的肋片高度(24 mm)和厚度(1~2 mm)。等效热路法可作为同类型LED灯具结构散热性能分析与优化的一种便捷而有效的研究方法。

According to the heat dissipation characteristics of a project lamp with high power LED array, the physical model of key structures for heat dissipation was established. And some mathematic models, which can express correctly the heat conduction and natural convection performance of above physical model, were selected based on equivalent thermal circuit method. Using these models, the heat dissipation performance of LED array was calculated in EXCEL software following the specified calculation procedure in this paper. Through comparison between the calculated temperature and the measured data obtained by infrared thermal imager, the calculation error of mean temperature is as low as +1.08%, so the validity of thermal circuit method is satisfactory for the given LED model. Subsequently, the influence trends of three key structural parameters on heat dissipation were analyzed separately in detail. The results show that heat dissipation performance can be improved obviously with an optimum fin spacing about 5 mm, and a higher fin height or a thinner fin thickness all can obtain a lower junction temperature, however, the best values of fin height (24 mm) and fin thickness (1~2 mm) should be determined to satisfy the demands of weight reduction, low-cost and manufacturability. Therefore, thermal circuit method can be effectively applied to thermal analysis and parameters optimization with the advantage of accuracy and swiftness.