• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2085-2087
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• 1998

This paper presents the design method of a dimming electronic ballast for fluorescent lamps using a frequency control IC, and investigates the effects of circuit variables on its dimming characteristics. It is shown that effective dimming is possible with IC IR2151 for frequency control, and this leads to a feasible design of more smaller and cheaper dimming ballast. Five ballasts different in the values of the series inductance and capactance are designed, and their dimming characteristics are compared. As the result, the dimming range becomes more broader as the series inductance gets smaller and the capacitance larger. Thus appropriate selection of the values of L and C should be made according to the types of application site.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.4
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• pp.201-205
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• 2004

The CCFL dimming control methods are generally used lamp current regulation or average current adjustment method feeding the CCFL inverter. Inverter operation frequency is higher than resonant frequency for safe operation. In this study, we design the half-bridge type series and parallel resonant converter circuit that switches at variable frequency modulation methods to control the output power. This method has advantages such as low EMI and reduced harmonics, and it is convenient for dimming control using a microprocessor. The validity of this study is confirmed from the simulation and experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.7
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• pp.1-7
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• 2013

LED lamps are appropriate to the light source for use in broadcasting lighting. When the lighting frequency of LED lamp is different from the shutter frequency of camera, however, the flicker appears on the moving image which is taken by the camera under the dimmed light of LED lamp with conventional dimming methods. In this study, a new dimming method for the LED lamps used as the broadcasting lighting is proposed to minimize the flicker. A lighting period in the proposed dimming method is divided into the several sub-periods which have weight of the bits. Also, the proposed dimming method has characteristics that are optimizing the turn-on timings of two LED lamps to reduce the turn-off periods of the lamps and not to overlap the turn-on periods of the lamps. In the experiments, the incidence of the flicker is taken by the camera under several lighting conditions of the conventional dimming methods and the proposed dimming method. In addition, the brightness values of the frames are obtained in the moving image, and incidence of the flicker is evaluated and compared with conventional methods. From the results, the incidence of the flicker in the proposed method is more improved than the conventional methods.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.193-198
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• 2009

In this paper, we developed remote dimming control system of electronic ballast for 400W metal halide lamp. This ballast could limit ignition current and soft start-up technique by the inverter with LCsCp resonance tank. The dimming circuit can dim from 400W to 200W by varying of the inverter switching frequency. The PLM consists of coupling circuit, BPF(Band-Pass Filter), FSK(Frequency Shift Keying) Modem and ${\mu}$-controller(Micro Controller). By coupling electronic ballast with PLM, the system that able to dimming the lamp through PLM is demonstrated by experimental results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1998.11a
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• pp.156-161
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• 1998

The purpose of this paper is to determine circuit parameters in the inverter part of the electronic dimming ballast for fluorescent lamps, that is adequate to use with the prevailing dimming controller IC. Firstly, the operating frequency characteristics are investigated by varying circuit parameters of electronic ballasts and are matched with the output characteristics of dimming ballast controller. Secondly, circuit parameter values are determined by using PSpice simulation and operating frequency characteristics. Finally its validity is verified from the electrical and light output characteristics on the prototype of the electronic dimming ballast.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.834-838
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• 2004

This paper presents the structure of a dimming control system for multiple fluorescent lamps. The dimming control system is composed of a phase angle controller, a transducer, and dimmable ballasts. In these ballasts, dimming control is achieved by varying the switching frequency that is controlled by the external DC level.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.6
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• pp.632-637
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• 2000

In this paper, to control with light dimming levels of the fluorescent lamps, we have used the power line instead of the signal line to transmit the control signals. To reduce the BER(Bit Error Rate) on the power line communication with the serious noise interferences. We have adapted the FSK(Frequency Shift Keying) modulation and demodulation technique. Since the electronic ballast produced the EMI(ElctroMagnetic Interference) noise in some frequency bands, we have reduced the EMI levels in the band below -50dB. By varying the switching frequency of the ballast for the FL032/T8 from 18kHz to 25kHz, it is possible that the dimming levels are controled with the range of 5∼100%

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.133-136
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• 2005

Recently, a drain of energy resources is issued seriously. The daylight responsive dimming systems can reduce electric energy uses. But, we cannot predict amounts of energy-saving and accuracy of system performance. Therefore, the purpose of this study is a development of software for the system performance of daylight responsive dimming systems. The principle of this software based on luminous flux transfer method and finite elements method. The control algorithm of this software and daylight responsive dimming systems use the same algorithm. In addition the advantages of this software are use to same algorithm of daylight responsive dimming systems, electric power-luminous flux data and rates of frequency of sky conditions. Therefore, this software can predict more correct calculation about illuminance and amounts of energy-saving of daylight responsive dimming systems.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.4
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• pp.177-182
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• 2003

We have proposed the dimming controller using the AC chopper technique. The AC chopper changes the amplitude of the input source voltage with the same frequency. The conventional dimming controller is operated by controlling voltage phase with the triac. It has bad characteristics of the input current THD and the input power factor But the dimming controller using the ac chopper technique has a low current THD and a good power factor. The developed dimming controller is consist of the IGBT and the low pass filter. The system is operated by the variation circuit of the input source voltage and the microprocessor.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.4
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• pp.177-177
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• 2003

We have proposed the dimming controller using the AC chopper technique. The AC chopper changes the amplitude of the input source voltage with the same frequency. The conventional dimming controller is operated by controlling voltage phase with the triac. It has bad characteristics of the input current THD and the input power factor But the dimming controller using the ac chopper technique has a low current THD and a good power factor. The developed dimming controller is consist of the IGBT and the low pass filter. The system is operated by the variation circuit of the input source voltage and the microprocessor.