• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1219-1221
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• 1997

Poly(1,4-phenylene(1-methoxyenthylene)), organic water soluble PPV precursor was synthesized for polymer electroluminescence(EL) device. To control the molecular array, deposition method of emitter was Langmuir-Blodgett(LB). PPV precursor layer was treated thermally to conversion of PPV. Optical, electrical and EL properties of PPV LB thin film was estimated. Homogeneous light emission of greenish-yellow in PPV LB thin film can be easily confirmed under normal lighting even at low driving voltage. Polymer EL device using PPV LB thin film as emitter materials had a possibility to apply to next generation display device.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.19-27
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• 2014

Exterior vertical illuminance is an important factor for lighting control. But, there are not many researches about the exterior illuminance on a vertical surface. In this study, we predicted the exterior illuminance on a vertical surface using vertical luminous efficacy. First, we calculated the vertical luminous efficacy according to the sky clearness category. And we performed the statistical analysis of the measured and the calculated illuminance with luminous efficacy. The MBE and RMSE of the predicted exterior illuminance were-1.2% and 15.5%, respectively. Second, the annual illuminance on a vertical surface calculated with the luminous efficacy and the short-term measured solar irradiance was suggested in this study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.744-748
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• 2002

This paper describes a power supply of a CW magnetron for driving a electrodeless plasma lamp. The proposed power supply consists of a power factor controller, a series resonant ZVS half bridge inverter, a high voltage leakage transformer, and two IGBT drives. From the simulation results, it was confirmed that the proposed circuits can control the input power of the magnetron up to 33.3[%] linearly by adjust driving frequency of the inverter.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.210-212
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• 2018

A new switching mode has been proposed to obtain high power factor and low THD in single stage AC-DC converter. The conventional voltage mode control in critical conduction mode distorts input current shape with poor THD in flyback topology. Once TRIAC dimmer is connected, visible flicker in the LED lamp is easily detected due to a lack of TRAIC holding current near the input voltage zero cross. The newly proposed method can shape the input current by providing a desired reference voltage so that low THD is obtained by ideal sinusoidal input current in case of no dimmer connection and flat input current performs good TRIAC dimmer compatibility in phase-cut dimming condition. To confirm the validity of the proposed method, theoretical analysis and experimental result from 8W dimmable LED lighting system are presented.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.99-102
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• 2001

In this paper, the electronic ballast was developed to control 250W metal halide lamp. To avoid acoustic resonance phenomenon, we calculated the acoustic resonance band and determined the driving frequence to from 70kHz to 100kHz. Due to the switching loss of MOSFET, many problems are caused in the inverter circuit during lighting the lamp, so we have reduced the loss by connecting the capacitor to reduce inrush current In this paper, main research area is to find the methods to operate the Iamp on regulated constant output. After detecting the current I and voltage V of the lamp, we changed the driving frequency by changing the DC voltage level.

• Journal of Industrial Technology
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• v.31 no.A
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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.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.185-191
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• 2006

Auxiliary power supply developed by domestic technology has very important function that not only effect on main power converter & inverter system, traction motor and train control system which are related to performance of train, but also influence on power supply for HVAC(Heat, Ventilation, Air-conditioning) and lighting device which are related to comfort of passengers. This paper shows characteristic test results of auxiliary power supply such as working condition and performance, which is associated with velocity of train, operating mode and surrounding equipment, through test running. Also it shows the results deduced from comparison analysis between designed data and manufactory test data as measuring in put voltage of auxiliary power supply. And, it propose a modification of design parameter for stabilizing operation and improving reliability.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.84-87
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• 2007

Auxiliary power supply developed by domestic technology has very important function that not only effect on main power converter & inverter system, traction motor and train control system which are related to performance of train, but also influence on power supply for HVAC(Heat, Ventilation, Air-conditioning) and lighting device which are related to comfort of passengers. This paper shows characteristic test results of auxiliary power supply such as working condition and performance, which is associated with velocity of train, operating mode and surrounding equipment, through test running. And, it propose a modification of design parameter for stabilizing operation and improving reliability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.795-798
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• 2011

태양전지를 이용한 LED 가로등 시스템은 태양광을 이용한 신재생에너지를 효율적으로 이용하기 위한 디지털제어 융합기술이다. 고휘도 LED(Light Emitting Diode)를 이용한 조명 시스템은 수명이 길고, 효율이 높고, 디지털 제어가 가능하여 백열등 및 형광등을 대체할 차세대 친환경 조명으로 주목받고 있다. 제안된 시스템은 태양광을 이용한 지능형 LED 가로등 전류 제어 시스템으로서, 배터리 수명을 연장하기 위하여 충전 방식 개선하고, 배터리 충전 상태와 조명시간에 따라 LED 방전 전류를 효율적으로 제어한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.5
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• pp.355-364
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• 2009

Electro-Luminescence (EL) sheets have been widely used in lighting displays, mainly used as advertisement panels. To drive the ELs in optimal conditions, it is required to understand the load profile of the EL. Hence, in this paper, a modeling for an EL sheet was performed to analyze the load characteristics of the EL. Based on the extracted model of the EL, a topology for inverter system was chosen and the optimal design parameters were obtained. The validity of the designed EL driver system was verified through computer simulations and experiments.