극저온에서 발광다이오드(LED)의 동작 특성에 관한 연구

Abstract

The interest in development on luminaires which are available up to -52℃ is surging as demands in vessels navigating a north pole route increase. A conventional incandescent lamp is operated stably at -52 ℃, but luminous efficacy is lowered less than 10lm/W. Also, lifetime is less than 1,000 hours, which is quite short. In additon, many countries including Korea have eliminated the use of incandescent lamps gradually since 2014.

In this thesis, therefore, to elicit design method of the LED luminaires that enables to substitute for incandescent lamp, has studied about cryogenic characteristics of LED packages, bulbs, driving circuit and power supply. This experiments were carried out according to standards IEC 60945-8.4.1. We analyzed and compared electrical and optical characteristics of LEDs, which are related to components and CFL in temperature range of -60℃∼25℃. In the case of the LED package, it was applied with the thermal analysis programs designed to optimal heat dissipation structure.

As a result of the test, on the basis of the 25℃, LED packages’s light output increased 1.7∼1.9 times at -60℃ and forward voltage of the warm-white and cool-white is respectively increased by 1.73V and 2.11V. And when LED package’s light output connected the driver, is increased to 1.6∼1.8 times. Forward voltage of the warm-white and cool-white is respectively increased by 1.49V and 2.11V. And the CFL’s light output is rapidly reduced as the temperature is lowered, and it does not light below -25℃. While all LED bulb’s light output is increased by 1.2 times at –60℃.

Regarding the performance of the LED driving circuit and the power supply at cryogenic temperatures, there was no problem with lighting and operations.