• Proceedings of the KIEE Conference
• /
• 2001.05a
• /
• pp.194-196
• /
• 2001

Light dimming is based on adjusting the voltage which gets to the lamp. Light dimming has been possible for many decades by using adjustable power resistors and adjustable transformers. The power electronics have proceeded quietly since 1960. Between 1960-1970 thyristors and triacs came to market. Using those components it was quite easy to make small and inexpensive light dimmers which have goof efficiency. This type of electronic light dimmers became available after 1970 and are nowadays used in very many locations like homes, restaurants, conference rooms and in stage lighting. But the problem of thyristor dimmer have been that it has poor efficiency and voltage drop. Recently IGBT(Insulated Gate Bipolar Transistor) control is a new way to do light dimming for improving this problems. IGBT dimmer has many other advantages over traditional thyristor dimmer there are no huge current spikes and EMI caused by turn on Using IGBT it is possible to make the turn-off rate relatively slot to achieve quite operations in terms of EMI and acoustical or incandescent lamp filament noise. For the development of IGBT dimmer. This paper shows the effects of IGBT dimmer compared with thyristor dimmer through a simulation using EMTDC.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.6
• /
• pp.706-713
• /
• 2020

To control the LED lighting for broadcasting, LED current control using tri-stimulus values is used for RGB LEDs. For the convenience of control, this control is approximated as a linear function or used as an appropriate value through trial and error. Also, it is not suitable for broadcast lighting because it does not use a diffuser plate applied for mixing sufficient light and color required for actual it. In this study, a neural network with excellent nonlinear function approximation is used as a control method for LED panels for broadcast lighting. We intend to implement an LED panels controller suitable for the desired chromaticity coordinates and dimming values of intensity. As a result of the performance evaluation, the errors of the xy chromaticity coordinates are mostly ±0.02 and the acceptable range of ANSI C78.377A was satisfied. The average errors of the xy chromaticity coordinate are xerror=0.0044 and yerror=0.0030, respectively, and we confirmed the superiority and stable performance of the proposed algorithm.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.21 no.3
• /
• pp.359-364
• /
• 2011

The study uses department of the sensitivity and fuzzy reasoning, one of artificial intelligence algorithms, so that develop LED lighting system based on fuzzy reasoning for systematical control of the LED color temperature. In the area of sensitivity engineering, by considering the relation between color and emotion expressed as an adjective word, the corresponding sensitivity word can be determined, By taking into consideration the relation between the brain wave measured from the human brain and the color temperature, the preferred lesson subject can be determined. From the decision of the sensitivity word and the lesson subject, we adjust the color temperature of RGB (Red, Green, Blue) LED. In addition, by using the information of the latitude and the longitude from GPS(Global Positioning System), we can calculate the on-line moving altitude of sun. By using the sensor information of both temperature and humidity, we can calculate the discomfort index. By considering the altitude of sun as well as the value of the discomfort index, the illumination of W(white) LED and the color temperature of RGB LED can be determined. The (LED) sensitivity lighting control system is bulit up by considering the sensitivity word, the lesson subject, the altitude of sun, and the discomfort index The developed sensitivity lighting control system leads to more suitable atmosphere and also the enhancement of the efficiency of lesson subjects as well as business affairs.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.2003-2004
• /
• 2011

최근 에너지 절감에 대한 문제가 대두됨에 따라 조명기구의 조도제어를 통해 에너지를 저감하는 방식이 요구된다. 본 논문에서는 조도제어가 가능한 LED 보안등의 구동회로를 구현하였고, 원격으로 조도제어를 하기위해 어떤 통신 방식이 적합한지를 설명하고 적합한 통신 방식을 제안 하였다. 또한 제안된 통신방식을 구현하여 LED 보안등의 조도제어 시스템을 구현하였다.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.1025-1025
• /
• 2015

본 논문에는 Flyback컨버터의 PWM방식과 조명용 LED 구동장치의 디밍에 의한 조명제어를 제안한다. 제안된 LED 구동회로는 Flyback 컨버터를 이용하여 교류 입력 전원을 직류 출력전원으로 변환되는 과정을 이해한다. 포터커플러의 역할과 그 Feedback원리 그리고 PWM방식으로 IC를 직접 제어하여 버스트 디밍을 구현하고 LED의 밝기 밝기 조절 및 불필요한 전력낭비를 예방하는데 목적을 두었다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.2
• /
• pp.367-372
• /
• 2017

LED illumination has been developed from simple illumination to human oriented multi-functional system depending on the IT convergence trends. Thus, the convergence of IT technology such as various types of sensor and communication functions with application software can make saving of energy, and there are also several needs about the tailor-made illuminations requirements for the diverse users who want to take their own colors, strengths of the light. For the adaption of these kinds of intelligent system illumination, user oriented sensor and control should be possible. The LED lighting control system transmits and receives data via the Bluetooth mesh network and provides functions such as LED lighting control, LED lighting condition monitoring, energy usage monitoring, and energy peak point management. Therefore, in this paper, we suggest wireless communication platform and control system for the LED illumination control. We can expect life extension of LED illumination, and energy saving through this suggested system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2009.05a
• /
• pp.117-120
• /
• 2009

New shading system, which is Grating Louver System into a pair glass, is proposed for integrated lighting system between Daylight Responsive Dimming Systems and shading system in this study. The optimized distance of louvers, which is to block direct sunlight into a space, is calculated. Grating Louver System was simulated using Desktop Radiance 2.0 of lighting simulation software for comparing daylight distribution and changes of control slope by distance from window to back wall with roller shading system controlled by sun profile angle.

• Journal of Digital Convergence
• /
• v.12 no.4
• /
• pp.311-318
• /
• 2014

This paper is to introduce a lighting source controller using high brightness LED to create a clear and reliable condition for an accurate measurement and testing, which is a core technology in clinical image system and mechanical automation system. This controller is designed to supply a stable power in a constant-current system by installing a high brightness LED driver, and to improve the reproducibility of brightness by using 32-bit ARM processor core, dividing brightness quantity into 256 levels, making the remote control and the external interface possible, and preventing and digitizing the brightness inaccuracy caused by errors of resistance values. This controller enables the lighting range to be wide and possible in a low lighting level compared to analog, adds the RS-485 communication function, and makes it for the users to control the on-off function and the dimming level by receiving date from an external device.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.2
• /
• pp.18-26
• /
• 2009

Daylight responsive dimming systems are one of lighting control systems which are to control artificial lightings using available daylight for energy savings. This system is not popular because useful daylight is usually blocked by uncontrolled passive shading systems in buildings. It is necessary to integrate daylight responsive dimming systems and automata! roller shading systems. In this research, mock-up test is performed to analyze the daylight distributions in three different rooms for integrated systems. Roller shades are installed in two rooms. One is fully downed and the other is controlled by sun profile angle. The other room has no shading system as a reference room.

• Journal of Broadcast Engineering
• /
• v.15 no.4
• /
• pp.461-473
• /
• 2010

Since eco friendly and power saving products recently got into the limelight for the protection of environment, LED light technology has caught much of attention as the next generation broadcasting lighting. The newly introduced light source has such advantages as higher efficiency, longer life and its slim and compact forms leading to conveniency in installations. When combined with digital light control it gives more dynamic and various features to lighting. In this paper, used CIE standard for measuring light sources by their purposes and forms to make a comparative analysis of spectral distribution and color rendition of LED light source to those of existing lighting systems. By means of the cast shadowing and color reproduction tests I also tried to figure out the effects of LED lighting design on TV visuals where higher quality is crucial with the audience's increasing demands for quality image.