• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.409-410
• /
• 2014

본 논문은 독립형 태양광 보안등에 적합한 전력변환기를 제안한다. 제안된 전력변환기는 플라이백-부스트 콤비네이션 전력변환기로 하나의 스위치로 독립형 태양광 보안등의 배터리 감압컨버터와 LED 구동용 승압 컨버터의 기능을 모두 수행한다. 또한 기존 플라이백 컨버터의 RCD 스너버 회로 대신, 출력에 직접 연결하여 누설 인덕터의 에너지를 출력으로 전달하여 손실을 줄이는 방법을 적용하였다. 제안된 회로를 검증하기 위해서 PSIM 시뮬레이터를 사용하였으며, 회로의 동작 및 구조를 설명하였다.

• Horticultural Science & Technology
• /
• v.31 no.1
• /
• pp.56-64
• /
• 2013

Recent unusual weather due to global warming causes shortage of daily sunlight and constitutes one of the primary reasons for agricultural damages. LED light sources are frequently utilized to compensate for the shortage of sunlight in greenhouse agriculture. The present study is aimed at evaluating formations of phytochemicals as well as growth characteristics of mature strawberry fruits ('Daewang' cultivar) during cultivation in a closed growth chamber equipped with artificial LED light as a sole light source. Each LED light of blue (448 nm), red (634 and 661 nm) or mixed blue plus red (blue:red = 3:7) was separately supplied and the intensity of each light was adjusted to $200{\pm}1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at plant level with a photoperiod consisted of 16 hours light and 8 hours darkness. Strawberries grown under mixed LED light of blue and red wavelengths showed a higher production of fruits than those grown under other LED treatments. Fructose, one of the free sugars, increased in mixed LED light-grown fruits. Anthocyanin contents were elevated remarkably in the mixed LED light-grown fruits compared with those in other LED treatments. Contrastingly, contents of total phenolics and flavonoids were not of much different from one another among the fruits treated with various LED lights. On the other hand, ripening of strawberry fruits was found to be faster when grown under blue LED light compared with other LED treatments. Moreover, antioxidant activities of blue or red LED light-grown fruits, respectively, were significantly higher than those of mixed LED light-grown fruits. We suggest that when daylight is in shortage during cultivation in a greenhouse, supplementation of sunlight with LED light, which is composed of blue and red wavelengths, could be useful for the enhancement of productivity as well as of free sugar content in strawberry fruits. In addition, for the strawberry culture in the plant factory, selective adoption of LED light wavelength would be required to accomplish the purpose of controlling fruit maturation time as well as of enhancing contents of sugars and antioxidants of fruits.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.05a
• /
• pp.110-112
• /
• 2011

LED조명장치는 기존 광원의 대체품으로 자동차분야, 특수조명, 디스플레이, 항공등 많은 분야에서 활용이 증가하고 있다. 일반적으로 RGB 멀티칩 LED는 천연색 구현이 가능하여 경관조명 또는 감성 조명용으로 적용되고 고출력 백색 LED는 실내외 일반조명 또는 특수조명용으로 적용되고 있으므로 광효율, 연색지수를 증가하기 위한 연구가 계속 진행 중이다. 본 논문에서는 다양한 마이컴 종류 중 하나인 Cypress사의 PSoC을 이용한 LED 조명의 자연광 구현에 대하여 연구하고자 한다. 이를 위해 사이프레스사의 EZ-Color 모듈을 이용한 다양한 색 구현보다 자연광을 구현하기 위한 색온도 가변에 중점을 두고 연구를 수행하였다. 기존에 제시된 날씨와 계절, 시간에 따른 태양광의 색온도 데이터를 이용하여 다양한 색온도를 나타내기 위한 RGB 색혼합 비율에 대해 연구를 수행하였다. 이 연구를 통해 인간을 위한 감성조명의 개발에 참고할 수 있도록 데이터를 제시하고자 한다.

• Journal of Digital Convergence
• /
• v.14 no.1
• /
• pp.181-187
• /
• 2016

Typical Retro-reflectors installed on road have problems such as limiting a driver's visibility at night when it is foggy or rainy. On the other hand, LED illuminated studs, called cat's eye system, extends a driver's visibility under these conditions. In this paper, we present a design of the LED cat's eye system using solar energy that can sustain vehicles with about 30-ton weight and is compliant with the IP68 code for water proof as IEC standard 60529. In addition, we propose a scheme of designing a LED driving circuit consuming low power to take into accounts cold weather or rainy season with limited sunlight. This LED cat's eye studs is currently installed and used on expressway and bike route nationally as well as overseas.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.11
• /
• pp.1093-1100
• /
• 2016

This study is to demonstrate the superiority and stability of the solar - wind power hybrid power generation system for street lamps using super capacitor EDLC(:Electric Double Layer Capacitor). It is aiming to apply the lighting device using LED light source as the load of solar-wind power hybrid power generation system for independent power source and to develop the street light system device with high output power generation system. Unlike conventional controllers, EDLC, which is used as an auxiliary device for storing the developed power in the battery, can guarantee the high output and long life of the battery.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2022.11a
• /
• pp.827-829
• /
• 2022

본 논문은 코로나19로 인해 발생하는 우울증을 개선하고 태양광 패널을 이용하여 친환경적으로 재배할 수 있는 "태양광 에너지를 활용한 지능형 자율이동 채소재배기"를 제안한다. 본 논문이 제안하는 주요한 특징은 다음과 같다. 첫째, 태양광 패널을 이용하여 재배기에 전원을 공급한다. 둘째, 카메라와 OpenCV를 이용하여 채소의 상태를 매일 확인 후 LED 색상을 조절하여 최적의 채소 성장 환경을 만든다. 셋째, 수위 센서와 모터 펌프를 이용하여 자동으로 물이 공급될 수 있도록 하고, 수온과 수질을 주기적으로 체크하는 등 Human task를 감소시킨다. 넷째, DC모터를 이용하여 실내·외로 자율이동을 하고, 액추에이터를 이용하여 채소가 햇빛을 최대한 많이 받아 성장할 수 있도록 한다. 제안하는 시스템은 가정에서 채소를 재배하는 방식에 IoT기술을 활용하여 사용자의 편의성을 증가시키고, 녹색식물을 통해 '코로나 블루'를 해소하고자 하는 사람에게 필요한 "태양광 에너지를 활용한 지능형 자율이동 채소재배기"의 개발을 목표로 한다.

• Current Photovoltaic Research
• /
• v.9 no.4
• /
• pp.128-132
• /
• 2021

Advances in screen printing technology have been led to development of high efficiency silicon solar cells. As a post PERx structure, an n-type wafer-based rear side TOPCon structure has been actively researched for further open-circuit voltage (Voc) improvement. In the case of the metal contact of the TOPCon structure, the poly-Si thickness is very important because the passivation of the substrate will be degraded when the metal paste penetrates until substrate. However, the thin poly-Si layer has advantages in terms of current density due to reduction of parasitic absorption. Therefore, poly-Si thickness and firing temperature must be considered to optimize the metal contact of the TOPCon structure. In this paper, we varied poly-Si thickness and firing peak temperature to evaluate metal induced recombination (Jom) and contact resistivity. Jom was evaluated by using PL imaging technique which does not require both side metal contact. As a results, we realized that the SiN_x deposition conditions can affect the metal contact of the TOPCon structure.

• Journal of Energy Engineering
• /
• v.26 no.2
• /
• pp.64-72
• /
• 2017

The performance analysis of the 70 W class LED lighting system suitable for the Middle East environment was performed using the lumped parameter model. The LED light is composed of a heating substrate, a heat pipe, and a heat sink. We divided the LED lights into four objects and applied energy equilibrium to each of them to establish four lumped nonlinear differential equations. The solution of the simultaneous equations was obtained by the Runge-Kutta method. Convective heat transfer coefficients of the lumped model were obtained by multidimensional CFD analysis. As a result of comparison with experiment, it was found that the heating substrate had an error of $1.5^{\circ}C$ and the upper heat sink had an error of $1.8^{\circ}C$ and the relative error was about 0.6 %. Using this model, temperature distribution analysis was performed for normal operating conditions with an ambient temperature of $55^{\circ}C$, with sunlight only, with abnormal operating conditions with sunlight, and without an upper heat sink.

• Proceedings of the KIPE Conference
• /
• 2017.07a
• /
• pp.196-197
• /
• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.12
• /
• pp.1-9
• /
• 2013

A standalone LED lighting system in using solar energy has been used usually less than 70W of lighting power because of a troublesome installation and maintenance. In this system, as more and more LED lighting power increases, the capacity of photovoltaic panel does proportionally, and to improve the charging efficiency of solar energy, MPPT(Maximum Power Point Tracking) techniques is used frequently, but the solar tracker is not. In this paper, a solar tracker which traces the light of the sun in varying hour to hour is studied to apply to the standalone LED lighting system. This solar tracker consists of twin axis for tracing the azimuth and altitude respectively, and it has a robust structure with safe mode to stand a strong wind. As a result of analysis, generating efficiency of the traced type has improved on the fixed one 28.84% on average.