• 전력전자학회논문지
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• 제17권1호
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• pp.34-40
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• 2012

In this paper, voltage clamped tapped-inductor boost converter with high voltage conversion ratio is proposed. The conventional tapped-inductor boost converter has a serious drawback such as high voltage stresses across all power semiconductors due to the high resonant voltage caused by the leakage inductor of tapped inductor. Therefore, the dissipative snubber is essential for absorbing this resonant voltage, which could degrade the overall power conversion efficiency. To overcome these drawbacks, the proposed converter employs a voltage clamping capacitor instead of the dissipative snubber. Therefore, the voltage stresses of all power semiconductors are not only clamped as the output voltage but the power conversion efficiency can also be considerably improved. Moreover, since the energy stored in the clamp capacitor is transferred to the output side together with the input energy, the proposed converter can achieve the higher voltage conversion ratio than the conventional tapped-inductor boost converter. Therefore, the proposed converter is expected to be well suited to various applications demanding the high efficiency and high voltage conversion ratio. To confirm the validity of the proposed circuit, the theoretical analysis and experimental results of the proposed converter are presented.

• 조명전기설비학회논문지
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• 제29권9호
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• pp.81-88
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• 2015

LED has been great attentions in lighting industry because of its long life-time, high efficiency, excellent light output characteristics. However, the life-time of the LED driving system is decreased because of the electrolytic capacitor which is used in the power conversion system for driving LED lighting. Therefore the capacitance reduction methods have been studied to replace an electrolytic capacitor with film or tantalum capacitor. This paper presents the Single stage PFC flyback converter with the simplified third harmonic current injection circuit to reduce output capacitance and the proposed system is theoretically analyzed and verified through the experiment.

• 전기학회논문지P
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• 제63권3호
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• pp.178-182
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• 2014

This paper investigates the lighting environment of railway system which are mainly used in KTX, Saemaul and Mugunghwa. When lighting used in KTX such as fluorescent lamp and incandescence is being replaced with LED lamp, illumination load of each railroad vehicle has been compared. The comparison result shows that the reduction of power consumption is 43.34% before and after the change. Also it has been performed the economic evaluation.

• 한국기계가공학회지
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• 제12권5호
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• pp.94-101
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• 2013

Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. The objective of this study is to implement the best plastic injection molding process for LED TV speaker frame. Moldflow analysis and simulation of plastic injection molding process were carried out in order to predict optimal modeling operation conditions and then injection molded part was produced various type of resin temperature, filling time and injection pressure variation. the result was that the best injection molding condition is set as 60bar pressure, 2sec filling time and $310^{\circ}C$ degree. The study result would be useful to variety of plastic injection molding process.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.415-416
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• 2013

본 논문은 LED구동회로 동작 시 전류와 광 출력의 변동폭을 최소화를 요구하는 LED 조명광원의 특성을 고려하여 소프트 스위칭을 할 수 있는 2차 공진 제안 회로로서 일반 인덕터의 정현적 전류와 콘덴서의 정현적 전압에 의해 이루어지는 특성을 반영하여 1차 공진회로에서 전압을 잡고 부하에 직렬로 인덕터를 삽입하는 회로를 구성함으로써 2차 공진회로를 구성할 수 있다. 따라서 본 논문에서 제안된 공진회로는 PISM을 이용한 시뮬레이션과 실험을 통해 제안된 알고리즘의 타당성과 우수성을 검증하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.885-889
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• 2006

Metro Subway System is widely known as the leader of public transportation in a metropolitan area. The signal interlocking is one of the most important organs that plays a major role in the system. By improving the quality of signal lights on the traffic system and keeping its maintenance on a high level will not only repair the current state, but it will also let the LED type signal semi-permanent. The device, which underwent a process of fine manufacture establishment and a close examination, obtained a patented article (2004, as a new device). Utilizing the equipment with cautious preservation on the system will enhance the current state of the signal device. Especially, the test for improvement and development based upon the technique that decreases the frequency of defect produced will further precipitate its efficiency. With authorization of imposing the LED lights on production, installment, and investigation of the system, the newly made equipment will bring improvement to the signal technology and to the industry at largest extent.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.246-247
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• 2012

역률개선용 AC/DC Flyback 컨버터의 경우 우수한 역률을 획득할 수 있으나 코어손실이 크고 효율이 낮으며 반면 Forward 컨버터의 경우 코어손실이 작아 높은 효율을 획득할 수 있으나 Dead zone이 존재하여 고역률 획득이 어려운 단점을 갖는다. 따라서 본 논문에서는 Forward 컨버터와 Flyback 컨버터의 장점을 동시에 구현할 수 있는 고효율 및 고역률 Balanced forward-flyback 컨버터를 제안한다. 제안된 컨버터는 스위치 온 시 Forward 컨버터로 동작하며 스위치 오프 시 트랜스포머 자화인덕터 리셋을 위해 Flyback 컨버터로 동작하므로 고역률 및 고효율 획득이 가능하며 Forward 및 Flyback 컨버터가 다루는 에너지량이 전류평형 캐패시터에 의해 항상 절반씩 배분되므로 AC입력전압의 크기에 관계없이 항상 고효율 획득이 가능하다. 제안된 회로의 타당성 검증을 위해 이론적 분석결과와 24W급 LED 조명 회로에 적용한 실험결과를 제시한다.

• 한국기계가공학회지
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• 제13권4호
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• pp.121-129
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• 2014

This study was carried out to develop an efficient plant growth system that can be controlled by altering the wavelength and illumination using a LED module. If it is possible to develop a system that can be controlled in this manner, utilizing different characteristics in the meaningful wavelength band depending on the growth time or type of plant, the plant growth conditions can be optimized. In order to this, red, green, blue and white LEDs are arrayed in a rectangle, consisting of LED modules which can be combined with each other. Consequently, the array can be used to select the optimal light conditions with monochromatic red, green, blue and white LEDs, or mixed LEDs, for plant growth. Experiments on the characteristics of the wavelengths to evaluate the efficiency of the plant growth system were performed. The usefulness of the system was demonstrated through a cultivation test involving several special plants.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.171-174
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• 2004

Concerning Korean energy consumption, 20% of the total electrical energy (96% is now exported) is consumed in lighting area. Accordingly, it is one of the most important governmental policies to efficiently utilize electricity due to development and application of high-efficiency lighting equipment. In Korea, widely-built traffic signals employ an incandescent and are of 100W/300 mm, and 280,080set/801,932lamps have been installed and operated by 1999. Of them, 58%(161,181set), 25%(69,655set) and 18%(49,244set) correspond to traffic signals, pedestrian signals and other supplementary signals respectively. It was estimated that electrical energy consumed 28MW instantaneously, 245GWH annually. On the other hand, the LED traffic signal is expected to be a future traffic signal since if traffic signals are replaced by LEDs, energy saving effect of 85% and drop of 75% in maintenance fee will be obtained. In this paper, the performance and characteristics of many LED traffic signals made in Korea are summarized in order to reform Korean standard of LED traffic signals.

• Journal of Applied Biological Chemistry
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• 제57권3호
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• pp.255-257
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• 2014

배추좀나방에 대한 light emitting diode (LED) 트랩의 시설재배지내 이용가능성을 평가하기 위해 LED 트랩의 유인활성을 광원이 장착되지 않은 no light 트랩과 상업적 대조구인 black-light 트랩과 비교하였다. 그 결과 green LED 트랩에서 가장 높은 유인활성을 나타내었으며, 상업적 대조구로 사용된 black-light의 경우 광원이 설치되지 않은 no light와 비교하여 유인활성을 나타내었으나 green LED 보다 낮은 활성을 나타내었다. 이러한 결과를 바탕으로 green LED 트랩이 시설재배지내에서 친환경적 해충방제법으로의 가능성을 보여주었다.