• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.49-52
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• 2007

In this paper, we proposed a design photovoltaic generation systems with SEPIC-Flyback converter. The SEPIC-Flyback converter is operated to SEPIC converter the state turn-on of the switch and the state turn-off the switch is operated Flyback converter. Therefore application rate of the core increases and voltage stress of switch and transformer decreases with active clamp operation. Also we performed MPPT(Maximum Power Point Tracking) control for efficient working of Photovoltaic Dower generation system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.762-767
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• 2010

This paper describes characteristic of a light triggered thyristor investigated by experiment to adopt it into a main switch of a pulsed power unit. Triggering principle of the light triggered thyristor are referred with its structure and equivalent circuit. Operational principle and simulation result of a capacitive pulsed power circuit are explained. A variety of triggering conditions of triggering circuit and characteristics on turn-on, turn-off, voltage dividing in series operation, overvoltage protection function of the light triggered thyristor are investigated by experiments. Experimental result of 40 kJ pulsed power unit using the light triggered thyristor is presented.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.8
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• pp.729-733
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• 2005

Al electrode for OLED was deposited by FTS (Facing Targets Sputtering) system which can deposit thin films with low substrate damage. The Al thin films were deposited on the cell (LiF/EML/HTL/Bottom electrode) as a function of working gas such as Ar or Ar+kr mixed gas. Also Al thin films were prepared with working gas pressure (1, 6 mTorr). The film thickness and I-V curve of Al/cell were measured and evaluated. In the results, when Al thin films were deposited using pure Ar gas, the turn-on voltage of Al/cell was about 11 V. And using the Ar:Kr($75\%:25\%$) mixed gas, the turn-on voltage of Al/cell decreased to about 7 V.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.263-266
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• 1990

In order to high-respone and high-reliability of devices, it depended upon how we can increase the high-frequency of the Inverter, UPS and it's application. but using high-frequency of self turn-off devices, it is important to reduce switching device loss and spike voltage of turn off. This paper proposed new methode about computer simulation of device loss also experimental results with switching device characteristic are presented.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.95-98
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• 2006

This paper proposes high speed SRM drive system for blower with a new 4-level inverter and precise excitation position generator. For the high speed blower, a proper inverter and control method are proposed and the output characteristics are analyzed. In order to get a fast build-up and demagnetization of excitation a current, 4-level inverter system is proposed. The proposed 4-level inverter has additional charge capacitor, power switch and diode in the conventional asymmetric converter. The charged high voltage is supplied to the phase winding for fast current build-up, and demagnetization current is charged to additional capacitor of 4-level inverter. In addition, a precise excitation position generator can reduce turn-on and turn-off angle error according to sampling period of digital control system. The proposed high speed SRM drive system is verified by computer simulation and experimental result.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.87-90
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• 2006

The direct instantaneous torque control (DITC) method is presented in this paper, which enables torque to be generated during all region and instantaneous torque control to be possible. The hysteresis control mode with the compared value between given torque and instantaneous output torque as input is applied in respect region. The output torque function, that is instantaneous output torque with the variation of current and position of rotor, is achieved by experiment. In this control mode the torque subsection function and current control are not needed. The turn on angle with variation of load torque and speed is only selected and turn off angle can be neglected. The validity of method is tested by simulation and experiment.

• 전자공학회논문지 IE
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• v.44 no.3
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• pp.1-5
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• 2007

A new field emission tip array was realized by Ti silicidation of Ti coated Si tip, which has long term durability, chemical stability, and high emission current density. The fabricated Ti silicided FE tip array under high vacuum condition of about $10^{-8}Torr$ shows that the turn-on voltage is about 40V and the emission current is about $69{\mu}A$ when the bias of 150V is applied between anode and cathode of $100{\mu}m$ distance.

• Proceedings of the IEEK Conference
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• 2000.06c
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• pp.47-50
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• 2000

In this paper, we propose a new destage algorithms, called the Dynamic Adaptive Threshold which determines turn-on and turn-off thresholds dynamically depending on the current write cache occupancy level and the differential rate of the host write requests. For performance evaluation, the proposed algorithm is compared with the wellknown High-Low Water Mark (HLWM) algorithm. Performance tests are fulfilled with our cached RAID 5 simulator. The simulation results show that the proposed algorithm outperforms the HLWM algorithm in terms of response time of host reads and write cache hit ratio under various workloads.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.609-612
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• 1996

This paper describes a design and implementation of the practical SMPS(Switched Mode Power Supply) with multi-output independent regulation scheme. The designed SMPS is applied to the PSU(Power Supply Unit) of high power GTO drivers for a inverter system. In order to accomplish precise voltage regulations for both turn-on and turn-off bias voltages of the GTO driver, the conventional forward type PWM converter scheme is adopted with the Post Regulator using a Saturable Reactor. Analytic design criteria and control schemes are described for practical applications. Finally, the precise regulation of multi-output voltages is proved by experimental results.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.63-66
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• 1996

An micro model for the power insulated Gate Bipolar Transistor(IGBT) is developed. The model consistently described the IGBT steady-state current-voltage characteristics and switching transient current and voltage waveform for all loading conditions. The model is based on the equivalent circuit of a MOSFET with supplies the base current to a low-gain, high-level injection, bipolar transistor with its base virtual contact at the collector and of the base. Model results are compared with measured turn-on and turn-off waveform for different drive, load, and feedback circuits.