• Journal of Power Electronics
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• 제16권4호
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• pp.1288-1297
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• 2016

This study proposes a single-stage light-emitting diode (LED) tube lamp driver with input-current shaping for T8/T10-type fluorescent lamp replacements. The proposed AC-DC LED driver integrates a dual-boost converter with coupled inductors and a half-bridge series-resonant converter with a bridge rectifier into a single-stage power conversion topology. This paper presents the operational principles and design considerations for one T8-type 18 W-rated LED tube lamp with line input voltages ranging from 100 V rms to 120 V rms. Experimental results for the prototype driver show that the highest power factor (PF = 0.988), lowest input current total harmonic distortion (THD = 7.22%), and highest circuit efficiency (η = 92.42%) are obtained at an input voltage of 120 V. Hence, the proposed driver is feasible for use in energy-efficient indoor lighting applications.

• 조명전기설비학회논문지
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• 제29권1호
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• pp.9-14
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• 2015

Due to the declining LED price and environment-friendly energy policies, CO2 emission reduction and energy-saving, the LED lighting industry is accelerating rapidly. In particular, the needs for LED lamp, replacing the existing fluorescent lamp without exchange luminaire or driver circuits, are also rapidly increasing. Therefore, replacement for T8 fluorescent lamp, LED T8 lamp was developed and standardized. However, except LED T8 lamps, other lamps' regulations or standards were not enacted. Also, the stability of fluorescent lamp substitutable LED lamp is low due to the difference in electrical characteristics and mismatch between the existing fluorescent lamp ballast and LED lamp. Therefore, many are struggling while developing fluorescent lamp substitutable LED lamp. In this paper describes the properties of existing fluorescent lamp ballasts and the considerations while developing fluorescent lamp substitutable LED lamp : demonstrating its validity by experiments the developed fluorescent lamp substitutable LED lamp prototype.

• 해양환경안전학회지
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• 제16권2호
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• pp.235-240
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• 2010

백열전구를 대체하기위한 친환경 에너지 절약형 7w급 LED 램프의 구동을 위한 전원장치를 설계하였다. LED 램프는 칩 LED를 여러개 직 병렬로 연결하여 사용하게 되므로 적합한 직류 전압과 전류를 공급하여야 한다. 그런데 LED 램프는 상용 AC 220V 전원에 직접 연결해 사용하게 되므로 드라이버에는 전압제어와 전류제어가 포함된 AC/DC, DC/DC 전력변환기가 반드시 필요하게 된다. 따라서 본 논문에서는 램프의 LED 열에 따라 출력전압과 전류제어가 가능하며 변압기가 없는 간단한 구조의 LED 램프 드라이버를 설계하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.382-384
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• 2013

LED는 일반 백열등에 비해 훨씬 밝으면서도 저전력이라는 장점을 지니고 있다. 이에 기존 형광등이 지니는 효율적, 환경적 문제점을 개선하기 위해 LED형광등의 개발과 상용화가 이루어 졌다. LED는 형광등과 달리 극성을 지니는 단방향성 소자로 교류전원을 직접 쓸 수 없기 때문에 전원공급장치를 필요로 한다. 이 전원공급장치는 부피가 크고 가격이 비싸기 때문에 유지비용면에서 일반 형광등에 비해 기능성이 떨어진다. 본 연구에서는 이 전원공급장치를 대신하여 간략하게 AC전원을 정류하고, 전압변동에 따른 전류변화로 인한 빛의 밝기가 변하는 현상을 없애기 위해 정전류로 제어할 수 있는 회로를 구성하고 이를 LED모듈과 구분하여 Plug in/out 방식의 교체형 모듈로 구성하여 유지보수에 있어 저렴하고 손쉬운 교체가 가능한 소자개발방법을 제안하고자 한다.

• 전기학회논문지
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• 제61권10호
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• pp.1513-1517
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• 2012

As demands for green industry increase, this paper proposes a power control technique that can substitute pre -existing CCFL(Cold Cathode Fluorescent Lamp) and optimize power consumption of LED BLU. This technique is designing LED driver circuit that make a DC-DC output voltage(VLED) to have a linear control function for a supply voltage of LED string. The proposed LED driver have an advantage that can increase or decrease a DC-DC output voltage compared with conventional LED driver. The designed LED driver circuit was designed using 0.35um CMOS technology. And its operation was verified through simulation.

• 한국산학기술학회논문지
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• 제13권12호
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• pp.6006-6012
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• 2012

태양광 가로등 시스템에 사용되는 전원 장치는 배터리 충전을 위한 충전기와 LED Lamp를 구동하기 위한 LED 드라이버로 구성되어 있는데 일반적인 시스템에서는 별도의 전원장치로 구성되어 있다. 본 연구에서는 충전기와 LED 드라이버를 한 개의 전원장치로 구성하였다. 특히 장치의 효율을 높이기 위하여 계통 연계형 태양광 발전시스템에 적용하는 최대전력추적(Maximum Power Point Tracking: MPPT) 방식을 충전기에 적용하였다. LED 드라이버에 필수적인 정전류 방식은 충전기의 전류제어 루틴을 사용하여 구현하였다.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4483-4488
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• 2010

LED는 다른 광원에 비해 동작수명이 길고, 친환경적이며, 에너지 효율이 높은 장점을 가지고 있다. 최근 LED 기술의 발전으로 인해 고휘도, 고용량의 LED가 개발됨에 따라, 표시장치에만 적용되던 LED를 조명장치에도 적용하는 기술이 확산되고 있다. 파워 LED는 동작의 안정성 및 신뢰성을 확보하기 위해 구동전류를 일정한 값 이하로 유지하는 전류제한기능이 필요한데, 본 논문에서는 전류제한기능을 포함한 하프브리지 LLC 직렬공진형 컨버터를 제안한다. 하프브리지 LLC 직렬공진형 컨버터는 다른 공진형 컨버터에 비해 상대적으로 입력전압 및 출력부하 범위가 광범위한 장점이 있으며, 변압기의 누설인덕턴스를 공진인덕터로 이용할 수 있기 때문에 마그네틱 소자를 줄일 수 있는 장점이 있다. 전류제한기능 및 역률개선기능을 포함하고 있는 출력전압 DC24[V], 200[W]급의 LED 조명장치 구동용 하프브리지 LLC 직렬공진형 컨버터의 설계 및 실험을 통해 타당성을 입증하였다.

• 전력전자학회논문지
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• 제21권1호
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• pp.42-48
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• 2016

Light-emitting diode (LED) drivers are recently replacing fluorescent lamps; these drivers can operate adaptively with various ballasts without modifying and removing such ballasts. To satisfy these trends, a LED driver that is compatible with both electronic and magnetic ballasts is proposed in this study. Unlike conventional LED drivers, the proposed driver has a ballast recognition circuit and a mode selection circuit to operate ballasts at optimal conditions. Therefore, it features low voltage stress, high efficiency, and good compatibility with both electronic and magnetic ballasts. Moreover, it can be compatible with a wide selection of ballasts from various manufacturers. To confirm the validity of the proposed LED driver, results of the theoretical analysis and experimental verification performed on a 15 W-rated prototype are presented.

• 조명전기설비학회논문지
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• 제27권3호
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• pp.16-25
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• 2013

Now it's a trend to install a series of white fluorescent light and orange high pressure sodium lamps because tunnel lighting should be opaque to the safety of drivers from soot, dust, humidity, and fog. Also fluorescent lighting is replaced to LED due to the fact that it improves amenity and object recognition and LED lighting has gradually been improved its nature. In this paper, we have implemented the circuits of the yellow series of high-pressure sodium lamps and white series of LED lights at one board to improve the transparency and recognition of objects. It is possible for inductive high-pressure sodium lamps and the capacitive LED drivers to circuit without power factor compensation. Two circuit parts share only a small number of parts, so low cost LED drivers compared to conventional ones are possible. Therefore, the implementation of the hybrid lighting with high-pressure sodium lamps and LED lights that can be driven at the same time by one driving circuit is possible. The LED capacitive power factor was 0.91 while individually implemented the sodium lamp power factor was 0.98. It shows not only the 2% improvement of hybrid forms but also the efficiency and THD.

• 한국기계가공학회지
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• 제17권6호
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• pp.117-123
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• 2018

Automotive headlamps have been continuously developed as one of the most important devices for securing the driver's view, and the LED lamps are getting popular in recent years. However, in case of the LED lamps, because the heat generated by the LED lamps are too high, it shorten the product life and lower the LED efficiency. Therefore, this study was investigated the cooling characteristics of the LED lamp heat sink for automobile by forced convection for LED heat generation control. In order to analyze the cooling characteristics of the heat sink, the temperature distribution results were investigated through the experiment and computational analysis under the increase of the air flow velocity, and the convective heat transfer coefficient was obtained. Also, convective heat transfer coefficient was calculated by the theoretical formula under the same condition and compared with experimental and computational results. From the result of this study, as the air flow velocity around the heat sink fins increased, the convective heat transfer coefficient significantly increased, confirming the improvement in the cooling effect.