Study on the heat dissipation performance of LED array using thermal circuit method

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.