• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.149-152
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• 2008

The purpose of this study is to develop a control software for daylight responsive dimming systems and automated roller shading systems. Developed software in this study is to used determinate sky conditions, calculation of solar profile angle, control height of roller shade, calculation of dimming level(%) for daylight responsive dimming systems.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.213-216
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• 2005

Recently, energy depleting problem have risen seriously. Many studies of daylight responsive dimming system for saving of lighting energy in office buildings have been done actively. Most of studies are focused on the accuracy. However if the variation of dimming levels is changed too often, occupants would feel uncomfortable. First, illuminance changes which occupants couldn't detect are studied through analyzing foreign studies. Second, workplan illuminance from daylight in each sky condition is measured. Because the dimming level In daylight responsive dimming system is dependent on the workplan illuminance from daylight. In conclusion, the most appropriate polling periods to daylight responsive dimming system for occupant's visual comfort was determined.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.313-317
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• 2004

This paper shows the structure of a control System for Fluorescent fin Dimming Ballasts. The control system is composed of phase angle controller, a transducer, many dimmable ballasts. For the implementation of the control system, We made a controller and the transducer that transform the phase angle controlled signal into the DC level. we used the conventional dimmable ballast In this ballast, dimming control is achieved by varying the switching frequency that is controlled by the external DC level. This has non-linear illumination characteristics as the dimming control. Therefore we compensate characteristics using the transducer proposed in this paper. We measured the illumination of two FL-28 lamps with dimming controller.

• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.30-36
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• 2022

In this paper, when the lighting and communication functions of the visible light communication system are used at the same time, we propose a technique to reduce the dimming level and flicker of the lighting. Visible light communication must satisfy both communication and lighting performance. However, the existing data code method results in reducing the brightness of the entire lighting. This causes deterioration of lighting performance and flicker phenomenon. To solve this problem, in this paper, we propose an adaptive learning code allocation technique that allocates binary codes to transmitted characters and optimizes and matches the binary codes allocated according to the frequency of occurrence of alphabets in character strings. Through this, we studied a technique that can faithfully play the role of lighting as well as communication function by allocating codes so that the 'OFF' pattern does not occur continuously while maintaining the maximum dimming level of each character string. As a result of the performance evaluation, the frequency of occurrence of '1' increased significantly without significantly affecting the overall communication performance, and on the contrary, the frequency of consecutive '0' decreased, indicating that the lighting performance of the system was greatly improved.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.44-53
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• 2013

This study has attempted to investigate how subjects perceive changes of brightness and their visual comfort according to daylight responsive LED(Light Emitting Diode) dimming systems in the office with venetian blind. Two studies was conducted. First study is that how subjects perceive changes of brightness and their visual comfort depending on angle control method of the venetian blind while the workplane illuminance level is being maintained through daylight responsive LED dimming system. Second study is that how subjects perceive changes of brightness and their visual comfort depending on the amount of daylight penetrated into the building while the illuminance level is being maintained through daylight responsive LED dimming system. The results of this study could be proposed as basic data in the control of the venetian blind and LED lighting in consideration of their perception on changes of brightness and visual comfort.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.9
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• pp.15-22
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• 2013

A new LED lamp driving technology with a charge pump instead of a conventional DC-DC converter is proposed. The proposed driving technology is used to control the LED lamp with digital dimming. The power loss in the zener diodes is reduced because the charging process of the capacitors is selectively controlled according to the digital control signal. From the experimental results, when dimming four LED lamps simultaneously, the average driving circuit efficiency of 89% is obtained, regardless of the dimming level. White light with color temperature over a range of 2800~7200K was produced by dimming control of red, green, blue and amber LED lamps with the proposed driving circuit. The characteristics of the driving circuits can be changed depending on the characteristics of the R, G, B, and A LED lamps. The efficiency of the driving circuits up to a maximum 89% can also be obtained depending on the combination of LED lamps. The driving technology with digital dimming control for LED lamps proposed in this paper would be effective for obtaining high efficiency in LED driving circuits and remote control of LED lamps using digital communications.

• Journal of the Korean Solar Energy Society
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• v.28 no.5
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• pp.36-48
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• 2008

This study examines the influence of control algorithms on dimming performance to determine appropriate control setting when direct/indirect lighting is controlled by a daylight dimming system. Computer simulation were performed for a small office with double skin envelope under various daylight conditions. A retractable fabric shading and Venetian blind were applied for internal and external envelopes under three CIE standard sky conditions. Unshielded and partially-shielded photosensors were used, and three control algorithms were applied for the sensors. In general, dimming level was too excessive due to the direct impact of light from lighting fixture to the photosensor. Providing insufficient lighting output, the unshielded photosensor completely failed to secure required illuminance under any daylight condition. When a partially-shielded photosensor was applied under clear sky, three setting points functioned effectively. Less sensitivity for the partially-shielded photosensor was effective to control the dimming system optimally with reasonable energy saving. However, the daylight dimming control system for direct/indirect lighting does not appear to be energy effective when photosensors without enough shielded area is installed on ceiling where light from fixtures reaches directly.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.109-113
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• 2011

This paper analyzes the noise sources of an LED lighting module with TRIAC dimming control and proposes an improved EMI filter design for the reduction of conducted noise emission. TRIAC dimming invokes problems of input oscillation and capacitor overvoltage at the lighting module. The proposed double LC filter reduces high noise level from the circuit. The experimental and simulation results show that this approach can make significant contributions to the reduction of conducted noise emission from an LED lighting module with TRIAC dimming control.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.103-107
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• 2006

In this paper, the dimmable electronic ballast for the 250W metal halide lamp was realized by three stage structure. We developed stable the dimming ballast by using a Micro-controller, and measured the output wattage in the dimming range(illumination) from 100% to about 20%. Under the 35% dimming level, it is possible to cause the redution of lamp's life. The dimming performance can reduce the light system's wattage but can reduce the luminance efficiency (lux/watt).

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.25-30
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• 2021

In this paper, we studied the coding technique for flicker mitigation and BER performance improvement in visible light communication system. In order to increase the transmission speed of visible light communication, a multi-transmission multi-LED transmission system using a plurality of LEDs is being actively studied. However, when data is transmitted through N LEDs in a multi-LED visible light communication system using N LEDs, there is a continuous zero section in which 0 is transmitted simultaneously according to the data sequence, and since the transmission section of 1 is different, flickering Or, a phenomenon in which the dimming level changes occurs. The visible light communication system is a communication system that simultaneously performs communication and lighting functions. Therefore, transmission efficiency of communication and brightness of lighting must be considered at the same time. To solve this problem, we proposed a flicker reduction mapping that can alleviate flicker and dimming level problems, improve error detection and BER performance through coding mapping of each LED data sequence.