• 한국인터넷방송통신학회논문지
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• 제17권5호
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• pp.71-78
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• 2017

본 논문에서는 멀티 홉 VLC 환경에서 디밍 제어를 이용한 각 변조 방식의 전력 성능을 분석 하였다. 성능을 분석하기 위해서 VLC기반 실내 멀티 홉 시스템을 구성하였으며, OPPM과 VPPM의 두 가지 변조 방식 기법을 적용하였다. 시뮬레이션은 송신 전력과 수신 전력을 고려하여 각 변조기법의 dimming 제어 및 홉 수에 따라서 수행하였다. 그 결과, 변조에 따른 송신 전력 및 수신 전력에서, dimming이 증가함에 따라, OPPM은 VPPM보다 적은 전력 성능을 갖으며, 수신 전력 대 홉 수 및 dimming이 50 % 일 때, 홉 수가 증가하고 거리가 길수록 VPPM 및 OPPM의 수신 전력은 급속히 감소하는 것으로 나타났다.

• Architectural research
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• 제7권2호
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• pp.47-54
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• 2005

A photoelectric dimming control system for a small private office space with a double skin envelope system was analyzed for the purpose of examining optimum control performances under a variety of daylight conditions. Computer simulations were performed for the three different photosensor types positioned at the center of ceiling in the space. They were applied in both a south and north-facing room. Daylight conditions were a fixed horizontal venetian blind on an external envelope and a retractable shading device on an internal envelope under a clear, intermediate and overcast sky at different times of a day and year. Partially-shielded photosensors provided good control performances providing the required electric light output under clear and intermediate sky conditions. Unshielded photosensors failed to provide necessary illuminance levels producing less electric output and fully-shielded photosensors generally provided excessive light output. Reasonable electric lighting energy savings were achieved except under overcast sky conditions where the control system did not contribute to energy savings due to the less daylight through envelopes. The retractable shading device covering 50% of the internal envelope reduced energy savings up to 19.62%, but the workplane illuminance levels were maintained within recommended ranges. The coefficients of determination between workplane illuminance and photosensor illuminance due to daylight ranged from 0.74 to 0.98. Partially-shielded conditions provided best correlations and the north-facing room yielded stronger correlation than the south-facing room.

• 센서학회지
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• 제30권4호
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• pp.196-203
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• 2021

In this study, an optical identification system was developed, wherein visible light is used to transmit the interrogating signal, and infrared is used to send the response signal. In the reader, visible light from a light emitting diode (LED) array was modulated via modified pulse width modulation for flicker-free illumination and dimming control. Moreover, the duty factor of the dimming control time was employed to control the illumination from the LED. In the transponder, the spike signal in the output of the high-pass filter was utilized to recover the interrogating signal while preventing interference from the 120-Hz noise from adjacent lighting lamps. The illumination was controlled in 26-86% range of the constant wave LED illumination by changing the duty factor from 20% to 90%. This configuration is advantageous for the construction of optical identification systems for automatic security check and car fare calculation at toll gates or parking facilities.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.71-74
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• 2002

We have development the dimming controller using the ac chopper technique. The ac chopper change the amplitude of the input source voltage with the unchanged its frequency. The conventional dimming controller is operated by controlling voltage phase and is consist of the triac. It has a bad characteristic about a current THD and a power factor. But the dimming controller using the at chopper technique has a low current THD and a good power factor. The developed dimming controller is consist of the MOSFET and the low pass filter. The system is operated by the variation circuit of the input source voltage and the microprocessor.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.163-166
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• 2004

The conventional fluorescent lamp dimming system using an another control line is complex and will increased the cost. Therefore, many studies have focused on the wireless communication, but it is not fit for dimming system because of the interference generated by the infra-red light of lamp or switching noises in ballast. So, we applied the power line communication on the dimming system and we proposed a new coupling circuit using the voltage controlled impedance convertor for improving the performance of the FH/SS PLC modem. The performance for the proposed modem is evaluted by the BER.

• 한국태양에너지학회 논문집
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• 제33권3호
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• pp.114-123
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• 2013

In these days, most of the office buildings are being required to save energy for maintenance. lighting system constitutes 20% to 30% of the total annual electrical energy consumption in office buildings. As an energy saving strategy for lighting system, dimming control system based on illuminance sensors came into use. But the system is accompanied with many illuminance sensors to control lighting and needs a lot of initial investment. In this study, the prediction equation for indoor daylighting illuminance distribution is proposed through the review for conventional research results and field measurements. The proposed equation was verified by the comparison between predicted results and field measurement results. The developed prediction equation for daylighting can be used to control the indoor illuminance level with the limited sensor when dimming control system is operated.

• 한국지능시스템학회논문지
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• 제17권4호
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• pp.540-545
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• 2007

본 논문에서는 지능형 Dimming Converter의 새로운 구조 및 설계 방법론을 소개하고 일련의 수치적인 실험을 통하여 제안된 모델 및 시스템을 평가한다. 기존의 형광 램프용 디밍 전자식 안정기는 전용의 디밍 IC를 사용하여 전자식 안정기 대비 최대 83%의 램프 및 안정기의 수명 연장을 가능하게 했다. 하지만 이러한 장점은 사용자가 디밍 컨트롤 스위치를 통하여 수동으로 제어를 해야 하는 불편함뿐만 아니라, 수동 제어가 불가능 할 경우 에너지 절약과 램프의 수명 연장의 실효를 얻을 수 없다. 따라서 본 논문에서는 간략추론 방식의 지능이론(Fuzzy Inference System)을 전자식 안정기에 접목하여 지능형 Dimming Converter 기반 전자식 안정기에 대한 연구 및 외부조도 조건과 사용자 설정에 따른 에너지 절약을 도모하는데 중점을 두었다. 또한, 제안된 시스템의 하드웨어에 지능 모델을 적용함으로써 기존 전자식 안정기와 성능평가를 통해 제안된 지능형 Dimming Converter의 우수성을 보인다.

• 설비공학논문집
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• 제23권3호
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• pp.231-242
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• 2011

This study examines influences of a daylight dimming control system on the variation of indoor illuminance and lighting energy savings in a small office space. Field measurements and a series of computation were performed for typical types of sky conditions in summer. Results indicate that the daylight illuminance under clear and partly-cloudy sky were close to the target illuminance during a majority of time due to a higher ratio of window to wall. However, the target illuminance was not kept successfully due to the variation of photosensor signals which were strongly influenced by desktop illuminance. The system with partially-shielded conditions succeeded to keep target illuminance under clear sky conditions. The system failed under overcast sky conditions since the electric light output from fixtures caused excessive signals to photosensors due to insufficient daylight on a desktop. Unshielded and fully-shielded conditions were not recommended for effective controls of the systems. The influence of lighting fixtures on photosensors should be minimized to achieve successful lighting controls by daylight dimming systems.

• 산업기술연구
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• 제31권A호
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• pp.95-101
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• 2011

According to recent technological developments in high-power LEDs, the stage lighting is one of most important areas to apply power LED system. Moving light for color rendering of stage uses the RGBW(red, green, blue, white) color mixing method. LED moving light system needs to have a wide range of dimming control as enough to operate at very low power. Also LED dimming system should not be induced color-shift and flicker in camera. This paper is experimentally verified the LED Moving Light driving circuit of 200Watt level designed to satisfy the above characteristics which applied the DC current-controlled and PWM mixed dimming method.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.104-110
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• 2011

High-brightness LED control is required for stable operation, thus the driver and control system must be designed to deliver a constant current to optimize reliability and ensure consistent luminous flux. In this paper, the sliding mode current controller is designed to adjust the illumination density of power LEDs. The controller design model of power LEDs, including its driving circuit, is proposed to realize the dimming control of power LEDs. A buck converter is introduced to drive the power LEDs and reduce the input voltage to a lower level. The sliding mode software controller is implemented to adjust the dimming of power LEDs. The proposed strategy for driving power LEDs is investigated and comparatively studied by experiments.