• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.196-197
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• 2017

최근 국내 태양광산업은 보급량이 증가하고 있고, 정부 정책에서도 에너지신산업을 추진하는 등 시장 활성화에 노력하고 있다. 본교에서는 신재생에너지원 중 태양광발전시스템에 대해 건학이념인 실사구시에 입각한 학부 교육 프로그램을 개발 및 적용하고 있으며 본 논문에서는 이에 대한 내용을 소개한다. 산업체 실무에 기초한 태양광발전시스템 학부 교육 프로그램은 마이크로콘트롤러(MCU) 교육, DC-DC 컨버터와 DC-AC 인버터 등 전력변환장치 기반의 Solar Explorer Kit 교육, 태양광발전시스템 발전량 산출과 손실분석 등 성능평가를 위한 PVsyst 엔지니어링 교육 내용으로 구성된다. 특히, 전력변환장치로 구성된 Solar Explorer Kit 교육 프로그램은 DC-DC 컨버터와 배터리(리튬-폴리머) 충전, 배터리(리튬-폴리머) 방전과 DC LED 부하 접속, 독립형 DC-AC 인버터 출력과 AC 할로겐 램프 부하 접속, 계통연계형 DC-AC 인버터 출력 실습 등에 대해 소개한다.

• 전기학회논문지
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• 제61권11호
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• pp.1625-1633
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• 2012

In the lighting industry, a Lighting Emitting Diode (LED) is increasingly used because of many advantages and a eco-friendly product comparing with the conventional lighting. However, the LED lighting has to include various AC/DC converters because the direct current is used for the LED lighting. Among a lot of power converters, the flyback converter is widely used for the LED lighting and includes some electrolytic capacitors for the voltage regulation. But the electrolytic capacitor has shorter lifetime than the LED element. It makes the expected life-time of the converter having the electrolytic capacitor shorter than the LED element. This paper proposes the single-stage PFC flyback converter without electrolytic capacitors. To verify the performance of the proposed converter, simulated and experimental works were carried out.

• 한국전자통신학회논문지
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• 제6권5호
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• pp.643-648
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• 2011

본 연구에서는 공항, 철도, 항만 등 대형 교통수단의 표시등으로 사용하기 위하여 SMPS에 의하여 구동되는 LED 신호등을 설계하고 제작된 LED 신호등의 전기적 특성과 EMI 특성을 조사하였다. 10V 이상의 교류 및 직류입력전압에 대한 출력전류는 1.67A이었다. 0.15~30MHz에서 측정한 잡음단자전압은 허용기준 준첨두치와 허용기준 평균치 보다 낮았으며, 30~1000MHz에서 측정한 잡음전계강도는 59.96MHz에서 $23.96dB{\mu}V/m$이었다.

• 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.

• 한국주조공학회지
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• 제21권3호
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• pp.179-186
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• 2001

Melt super-heating which promotes shape modification of ${\beta}$ intermetallic compounds was conducted to improve mechanical properties of recycled AC2B aluminum alloy. Modification of needle-shape ${\beta}$ intermetallic compounds was effective for the specimens of AC2B aluminum alloys containing 0.85wt.% Fe by melt super-heating, in which the melts had been held at $850^{\circ}C$ or $950^{\circ}C$ for 30 minutes respectively. Owing to the modification of needle-shape of ${\beta}$ intermetallic compounds by melt superheating of the alloy with containing 0.85wt.% Fe to $950^{\circ}C$, increases in elongation and tensile strength were prominent to be more than double and 55% respectively in comparison with the melt heated to $740^{\circ}C$. Moreover, modification of needle-shape ${\beta}$ intermetallic compounds in the alloy containing O.85wt.% Fe by $950^{\circ}C$ melt super-heating led to 48% improvement of the value of impact absorbed energy as compared with the melt heated to $740^{\circ}C$.

• Toxicological Research
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• 제14권2호
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• pp.177-181
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• 1998

Dithiocarbamate and mixed disulfide containing allyl functions were designed and synthesized as putative chemopreventive agents, i.e. N,N-diallyldithiocarbamate (DATC) and S-(N,N-diallyldithiocarbamoyl)-N-acetylcysteine (AC-DATC). DATC and AC-DATC were administered and the activities of cytosolic glutathione S-transferase (GST), glutathione reductase (GR) and microsomal N-nitrosodiethylamine (NDEA) deethylase were assayed in order to test the effects of these organosulfur com-pounds on the detoxification and metabolic activation system of NDEA. The amounts of hepatic glutathione (GSH and GSSG) was also determined. The administration of DATC to rats led to an increase in the activity of GR and to an inhibition of CYP2E1-mediated NDEA deethylation. AC-DATC induced the activity of GR and GST, increased the hepatic GSH content and inhibited the rate of NDEA deethylation. The level of GSSG was decreased as a consequence of the increased activity of GR. These effects may contribute to possible antimutagenic and anticarcinogenic action of the dithiocarbamates investigated.

• 마이크로전자및패키징학회지
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• 제12권2호
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• pp.135-140
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• 2005

Although it was recently observed that severe fatigue damage was formed in Al or Cu interconnects due to the cyclic temperatures generated by Joule heating of the metal lines by the passage of alternating currents (AC), AC loading frequency effect on the damage evolution characteristics are not known so far. This work focused on the effect of AC loading frequency (100 Hz vs. 10 kHz) on the thermo-mechanical fatigue characteristics by using polycrystalline sputtered Cu lines with temperature cycles with amplitudes from 100 to $300^{\circ}C$. It was consistently observed that higher loading frequency accelerated damaged grain growth and led to earlier failure irrespective of Cu grain sizes. The frequency effect is believed to result from differences in the concentration of defects created by the deformation-induced motion of dislocations to the grain boundaries.

• 조명전기설비학회논문지
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• 제23권12호
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• pp.10-22
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• 2009

본 논문은 독립적으로 LED의 색온도와 조도를 제어하는 알고리즘과 이를 이용한 LED 조명 시스템을 제안한다. 제안된 알고리즘이 항상 해를 가지는 것을 증명해 제안된 알고리즘이 유효함을 보여주었다. 적색, 녹색, 청색, 백색 (RGBW) LED를 사용한 LED 모듈 제어에 제안된 알고리즘을 적용하였다. 이 모듈의 색온도는 3,500~7,500[$^{\circ}K$], 조도는 500~1,500[lux] 범위에서 변화했다. LED의 접합온도가 40[$^{\circ}C$]로 유지될 때, 이 범위 내에서 색온도와 조도의 편차는 0.8[%] 이하였다. 30~70[$^{\circ}C$]의 범위에서는 목표 조도와 색온도가 각각 1,000[lux]와 6,500[$^{\circ}K$] 일 때 조도와 색온도의 편차가 2.1[%]와 3.1[%] 이하이고, 온도 보상된 경우에는 편차가 1[%]와 0.49[%] 이하였다.

• Journal of Power Electronics
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• 제15권2호
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• pp.555-566
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• 2015

A TRIAC dimming LED driver that can control the brightness of LED arrays for a wide range of source voltage variations is proposed in this paper. Unlike conventional PWM LED drivers, the proposed LED driver adopts a TRIAC switch, which inherently guarantees zero current switching and has been proven to be quite reliable over its long lifetime. Unlike previous TRIAC type LED drivers, the proposed LED driver is composed of an LC input filter and a variable switched capacitance, which is modulated by the TRIAC turn-on timing. Thus, the LED power regulation and dimming control, which are done by a volume resistor in the same way as the conventional TRIAC dimmers, can be simultaneously performed by the TRIAC control circuit. Because the proposed LED driver has high efficiency and a long lifetime with a high power factor (PF) and low total harmonic distortion (THD) characteristics, it is quite adequate for industrial lighting applications such as streets, factories, parking garages, and emergency stairs. A simple step-down capacitive power supply circuit composed of passive components only is also proposed, which is quite useful for providing DC power from an AC source without a bulky and heavy transformer. A prototype 60 W LED driver was implemented by the proposed design procedure and verified by simulation and experimental results, where the efficiency, PF, and THD are 92%, 0.94, and 6.3%, respectively. The LED power variation is well mitigated to below ${\pm}2%$ for 190 V < $V_s$ < 250 V by using the proposed simple control circuit.

• 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.