LED Lamp용 SMPS 열화실험 설계 및 분석에 관한 연구

Abstract

Recently, the lighting market is showing a trend of increasing prevalence of various lighting products, due to the increases in national income and industrial development. Among the lighting products, LED lightings are replacing existing lighting as an environment-friendly and energy-saving industrial product since 2000s. LED lightings have made ​​continuous technology development and the LED lightings market is expected its rapid growth for the future. As demand of the LED lightings are increasing reliability, light weight and high efficiency of the power supply have become necessary elements of LED lightings. The SMPS(Switching Mode Power Supply) is a device that meets these requirements. The SMPS which uses a high speed witching system makes possibilities of miniaturization and high efficiency of the light product. So the use of the SMPS is gradually expended as a lighting industrial trend. In the past, the study of lighting was focused on the efficiency and miniaturization of the SMPS but nowadays reliability and safety requirements are more required to study due to the increases of domestic use. The fire accidents which occur from the mechanical factors of electronics are counted around 14,500 cases(34%) causing 400 people casualties(20%) and 9,000 billion won in property damage(30%) as the annual average in last three years, and the electronic fire accidents are not reducing each year but rather increasing. The SMPS of LED lighting is considered as one of the major causes for electronic fire accident, as it takes the fifth position of reasons for domestic fire. The main reason for the fire and the electric shock causing from the SMPS is deterioration of the product due to long-term use. The expansion and the diversification of imported items are also one of main factor for increasing percentage of the fire and electric shock accidents of LED lighting power supply. The manufacturers have also tried to prevent the increase of fire and electric shock accidents through an improvement in manufacturing technology and quality of product. However, there is a limit that prevents the fire and the electric shock accidents from the degradation products. The SMPS for conventional LED lighting is under KC(Korea Certification) certification exam as a target product safety certification. Aside from it, there are a variety of criteria, such as KS (Korea Standard), MIL standard. However, as those criteria are standards for safety and quality aiming at new product, it is not appropriate to apply the standard to deteriorated product due to prolonged use. In this thesis, I proposed design and analysis of degradation test for LED lamp SMPS. I designed FTA(Fault Tree Analysis), FMEA(Failure Mode and Effect Analysis) in order to analyze the mechanism of the degradation for LED lamp SMPS and designed durability experiments on environment(high temperature operation test, high temperature high humidity operation test, high temperature operation test, high temperature operation test, high temperature high humidity non operation test, high temperature non operation test)experimented through the two-step QFD(Quality Function Deployment) and tested on designed tests. After test, I performed reproducible tests through environmental conditions on the PCB electrochemical-migration. Finally, according to results of the reproducible test, quantity of the product sample were determined for degradation test. Different models were also become as subjects on the test in order to verify adequacy of the proposed test method and the tests were successfully verified its adequacy. Now degradation mechanism of the SMPS for LED lamp relating fire and electric shock due to deterioration of the product could be detected at early stage of product manufacture by using proposed test methods.