• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2262-2267
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• 2010

In order to analyze the reason of wall blackening, which affect the decline of lifetime in a ceramic metal halide lamp, we carried out the deterioration of ceramic tubes by a change in operating conditions with arc tubes of two types of spherical and cylindrical, and we have confirmed the cause of wall blackening through the analysis of element composition and spectrum from SEM/EDS and spectrum analyzer. Wall blackening of tungsten was shown by sputtering from ignition in 20 minute on/off condition and wall blackening from chemical reaction between PCA wall and rare earth halides was shown significantly in a condition without on/off test. Especially, the wall blackening and the decline of luminous flux were reduced by inner convection in spherical type arc tube. Moreover, the color temperature and color coordinate were changed by reduction of emission spectrum of Dy which causes the chemical reaction with PCA wall.

• Transactions on Electrical and Electronic Materials
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• v.17 no.2
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• pp.79-85
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• 2016

In this study, we proposed a new single-stage small power MH lamp electronic ballast and power-factor correction circuit with improved circuit by the current of passive power factor correction. Main circuit integrates traditional DC/DC and DC/AC circuits into one-stage DC/AC inverter. Moreover, we described the working principle and control strategy of the new circuit; it's soft switching principle; and resonant element parameter design formula. An experimental prototype of HID lamp electronic ballast with output power of 70 W was built to verify the feasibility of the analysis and design. The simulation and experimental results proved that the power factor of this circuit could reach 94%, with efficiency of 90%. The input current harmonics conform to IEC 61000-3-2 standards and its cost is low. These superior performances of the new circuit indicate certain practical values.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.2
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• pp.18-25
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• 2002

In this paper, We have researched about the Electronic Ballast for 250W HPS(High Pressure Sodium) lamp. This Electronic Ballast is capable to operate the Ignition and Steady State Using the Class D LCC resonant tank, and minimizing the full-bridge inverter's Switching Stress by implementation Quasi-square ZC-ZVS Soft Switching Method. And also, We have reduced the heat of MOS-FETs and high frequency switching surge noise using the RCD damp snubber. Therefore, We are sure that the developed ballast has the properties of the stable & reliable Control and the function of minimizing the total noise of the system.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1005-1006
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• 2008

기존의 전자식 안정기 특히 펄스로 시동되는 HID램프용의 안정기에서는 부가적인 시동회로가 필요하게 된다. 하지만 램프 제조업자에 의해 규정된 점화 펄스폭은 제조업자 간에서도 다양하며, 대단히 높게 되어 있으며 그 펄스폭에는 최소 필요한 값이 있고 이것은 통상 $1.5{\sim}2.5us$정도이다. 이와 같은 시동 펄스폭의 조건을 만족하기 위해서는 시동회로 또한 복잡해지고 제작비용도 고가가 된다. 본 연구는 전력소모가 20[%]이상 절감되면서도 광량이 더 많이 방사되는 메탈핼라이드 램프를 UV경화 시스템 즉, LCD, PDP OLED 모듈조립, 평면, 곡면 스크린 인쇄용, 코팅용, 실험용 UV경화 및 UV노광 시스템 등에 사용 가능한 전자식 안정기를 고주파 시동의 이점을 유지해 가면서 지연 시간에 기인하는 램프의 꺼짐 및 대순환 전류의 문제를 해소하고 고압 대용량 램프를 구동할 수 있는 20KW급 전자식 안정기를 제안하여 22KW UV LAMP를 사용하여 전자식 안정기를 구동 실험으로 검증하였다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.4
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• pp.35-42
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• 1991

Recently, HID lamps have been considered as important in regard to the trend of energy saving, and increasingly and diversely used in various ways. This paper will show the simulating models concerning high-pressure arc discharge system directly applicable for its design and manufacture, and analyze its various characteristics. For warm-up characteristics, the evaporating process of inner atoms is described in terms of second-order differential equation: for the thermal conduction from are axis to discharge wall and outer bulb, its transfer process is introduced according to five first-order differential equations. Under the steady state satisfying LTE, the time-variant characteristics are suggested by means of time-dependent energy balance equation derived from fluid equations, approximation of radiation energy and material functions in the discharge tube. The simulating models concerning these equations are then applied for high-pressure mercury lamp.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2163-2165
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• 1998

This paper presents an adaptive control scheme of a ballast for HID lamp for an automotive headlight. A flyback converter is used for the voltage step-up and for the control. A full bridge inverter is used as a ballast topology. The proposed control method is an adaptive output power control with a charge control. The developed ballast satisfies the requirement of a fast warm up characteristics and operating stability for an automotive application.

• Journal of Power Electronics
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• v.10 no.5
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• pp.451-460
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• 2010

This paper presents a new kind of digital control metal halide lamp electronic ballast. A zero-voltage-switch quasi-square-wave (ZVS-QSW) dual Buck converter is adopted here. In this paper, a digital control method is proposed to achieve ZVS for the converter. This ZVS can be realized during the whole working condition. Single-cycle-peak-current control is proposed to solve the problem of excessive inductor current during a low-frequency reversal transient. Power loop control is also realized and its consistency for different lamps is good. An AVR special microcontroller for a HID ballast is used to raise the control performance, and the low-frequency square-wave control method is adopted to avoid acoustic resonance. A 70W prototype was built in the laboratory. Experimental results show that the electronic ballast works reliably. Furthermore, the efficiency of the ballast can be higher than 92%.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1890-1892
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• 2002

The technology of sulfur lamps that has physical and electrical characteristics comparable to current HID source has been reported. The fundamental principles of the operation of microwave discharges that are used to convert microwave energy to broad spectrum visual light are known. In this paper, emission dependance of microwave discharges in mixture content of sulfur with noble gases was studied. It is shown that the excitation of this gaseous mixture is carried out in two phases: (l) ionization of noble gas atoms by a microwave field and (2) the consequent maintenance of slightly ionized nonequilibrium plasma by the field. These two processes have essentially various thresholds for the microwave pump. The purpose of this work is to investigate spectral properties of the high frequency discharges in a mixture sulfur vapors with noble gases.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.168-171
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• 2006

After an incandescent lamp developed as a first light source using electric energy in 1879, various lamps have been developed and promoted for usual convenience. Although lots of light sources have been developed for the past centry, among them some were used widely but some were hardly used contray to the initial expectations. Incandescent, fluorescent, HID and LED lamps which are normally used these days were treated as new type of light sources and very difficult to be popularized at the initial stage. In spite of the initial difficulties, these light sources and luminaries are still so popular because all of them were improved to be used easily by reflecting human's mental and physiological state. Like this when new light sources and luminaries are developed, a careful consideration, if these are proper for the surroundings or not, must be preceded. This study finally derived development factors of PLS developed in domestic to be played an important role in future light by analyzing product trends, social and lighting development changes.

• Journal of the Korean Professional Engineers Association
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• v.19 no.2
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• pp.10-20
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• 1986

This paper describes a countermeasure of electric utilities and customer equipment in order to minimize an effect of sensitive electrical and electronic equipment on the voltage disturbances. After being studied, some schemes to solve were discovered. Firstly, in the electric utilities, the reduction of frequency and influence of voltage drop's time are not easy to realize because of the standpoint of effect and economy. Secondly, in the customer equipment, there are some equipment to minimize the voltage disturbances, Such as an UPSs, a noise suppressors and a power conditioners. One of them should be established on the computer control and automated systems, the electromagnetic switch of delay-release type should be adopted on the electromagnetic switch, the controlling circuit should be adopted on the variable speed motors which is being considered a countermeasure for a momentary under-voltage drops, the luminaire adhering a instantaneous restrike device should be adopted on the HID lamp. And also, the scheme of extending a setting time of relay on the undervoltage relay and the forming method of sequence which is automatic reclosing at this time of instantaneous suspension of an electric supply have been studied.