• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.723-727
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• 2004

A new high-performance and low cost single switch energy recovery display driver for an AC plasma display panel (PDP) is proposed. Since it is composed of only one auxiliary power switch, two small inductors, and eight diodes compared with the conventional circuit consisting of four auxiliary power switches, two small inductors, eight power diodes, and two external capacitors, it features a much simpler structure and lower cost. Nevertheless, since the rootmean-square (RMS) value of the inductor current is very small, it also has very desirable advantages such as n low conduction loss and high efficiency. Furthermore, there are no serious voltage-drops caused by the large gas-discharge current with the aid of the discharge current compensation, which can also greatly reduce the current flowing through power switches and maintain the panel to light at n lower sustaining voltage. In addition, all main power switches are turned on under the zero-voltage switching (ZVS) and thus, the proposed circuit has a improved EMI, increased reliability, and high efficiency. Therefore, the proposed circuit will be well suited to the wall hanging PDP TV. To confirm the validity of the proposed circuit, circuit operations, features,and design considerations are presented and verified experimentally on a 6-inch PDP, 50kHz-switching frequency, and sustaining voltage 141V based prototype.

• Progress in Superconductivity and Cryogenics
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• v.14 no.3
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• pp.53-59
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• 2012

Adiabatic demagnetization refrigerator (ADR) for hydrogen re-liquefaction operating between 24 K and 20 K has been designed. $Dy_{0.9}Gd_{0.1}Ni_2$, whose Curie temperature is 24 K, is selected as a magnetic refrigerant. The magnetic refrigerant powder is sintered with oxygen-free high purity copper (OFHC) powder to enhance its effective thermal conductivity as well as to achieve relatively high frequency. A perforated plate heat exchanger (PPHE) operated with forced convection is utilized as a heat switch. The forced convection heat switch is expected to have fast response relative to a conventional gas-gap heat switch. A conduction-cooled high Tc superconducting (HTS) magnet is employed to apply external magnetic field variation on a magnetic refrigerant. $2^{nd}$ generation GdBCO coated conductor HTS tape with Kapton$^{(R)}$ insulation (SUNAM Inc.) will be utilized for the HTS magnet. The magnetization and demagnetization processes are to be achieved by the AC operation of the HTS magnet. The designed magnetic field and target ramp rate of the HTS magnet are over 4 T with 180 A and 0.4 T/s, respectively. AC loss distribution on HTS magnet is theoretically estimated.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1069-1071
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• 1999

Closing switch는 여러 가지가 있으나, 방전시 발생하는 Z-pinch로 인한 전극의 손상으로 수명이 짧고, 소음, 열 발생 등으로 소형화가 문제점으로 되어왔다. Inverse pinch현상을 이용하여 기존의 closing switch보다 전류밀도가 1/62, 주울열의 발생, 인덕턴스가 작다. INPIStron의 수명에 영향을 미치는 절연물질은 세라믹을, 도전체로서는 경제성을 감안하여 쉽게 구할 수 있는 구리를 이용하여 제작하였고, 트리거는 gas-puffing방식을 사용하였다. 또한 이렇게 제작된 INPIStron을 이용하여 2MJ-500kA급 pulsed power 전원 장치를 개발하였다.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.657-659
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• 1993

We have developed a repetitive TEA $CO_2$ laser excited by a magnetic switch pulse source, and have measured the laser output energy for the mixing ratio of the laser gas mixture in single pulse. As a result of experiments, we have obtained the laser output energy of 252 mJ($\eta_{intrinsic}$=7.8%) in $CO_2:N_2$:He=1:1:8(1 atm.). At a repetition-rate frequency of 10 Hz, an average laser power of 1.5 W was obtained.

• Progress in Superconductivity and Cryogenics
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• v.10 no.4
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• pp.13-17
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• 2008

This paper presents experimental and characteristic analysis of hgh-$T_c$ eater-triggered witch using coated conductor (CC) in liquid and gas helium. The high temperature superconducting insert coil which can be installed in a low temperature superconducting (LTS) magnet has been proposed and researched to generate higher magnetic field for MR. Since CC could be an attractive option for HTS insert, it is important to research he characteristics of heater-triggered switch employing CC. We performed the heater test and constructed simulation model using finite element method (FEM.) We performed a protection test and observed normal zone propagation (NZP) signals to evaluate the witch with protection of magnet.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.385-390
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• 2006

A fast response $CO_2$ analyzer has been developed to study transient characteristics on an SI engine. The analyzer has the delay time of 4.5 ms and time constant of 2.8 ms, which is fast enough to measure $CO_2$ concentration on a transient condition. Wide range of A/F(Air/Fuel) ratio can be estimated using the analyzer with an additional switch type oxygen sensor. The results of measurement of $CO_2$ concentration and A/F ratio on a transient condition including rapid acceleration/deceleration and EGR(Ehxaust Gas Recirculation) on/off are presented and compared with a commercial exhaust gas analyzer and UEGO(Universial Exhaust Gas Oxyzen) sensor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.476-477
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• 2007

This paper described the partial discharge (PD) measurement techniques for diagnosing gas-insulated switches in overhead power distribution system. A capacitive voltage probe to detect PD pulse was designed and fixed on the surface of a bushing. We also designed a coupling network to attenuate AC voltage by 270 dB, and a low-noise amplifier having the gain of 40 dB and 500 kHz~20 MHz 3 dB. From the calibration, it was calculated that the sensitivity of the measurement system was 0.94mV/pC. In the application experiment, we could measure a PD pulse of 45 pC.

• Journal of the Korean Institute of Gas
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• v.26 no.1
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• pp.1-6
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• 2022

This paper is a purpose to study and analyze the engine starting failure examples for LPG car. The first example, the researcher verified the phenomenon that didn't supply the fuel because of filter clogging by fine alien substance in the gas valve line when he inspected the emergency cutting valve. The second example, there was no the influence of gas leakage when the solenoid operated at first. But the damage part of solenoid assemblying face wad downed a durability according to running a valve. Eventually, the researcher checked on the phenomenon of engine stopping by no gas feeding in solenoid because of leaking of gas. The third example, the researcher sought that the wiring sheaths of connector fin between EGR 10A fuse and LPG switch verified the burn-out phenomenon due to the bad contacting as tension damage produced the overheating. Therefore, the manager of a car has to do pre-inspection no producing electric failure and he must maintain his car with optimum condition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.4
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• pp.386-391
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• 2022

The gas insulation switchgear, which is a device for protecting a power system, cannot be supported by the insulation gas itself in a charge unit stored in a metal container. Therefore, molding technology is required to manufacture a gas insulation switch spacer. The APG method injection molding simulation was performed by applying the variables obtained through the physical properties of an epoxy composite used for manufacturing an insulating spacer to a moldflow software. After varying the temperature conditions of heater in the simulation, the thermal characteristics and the degree of hardening of the spacer were analyzed, based on which the optimum process conditions are presented.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.51-55
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• 2007

Generally, PLC (Power Line Communication) based home automation devices such as wall switch, walt socket, gas controller, etc, must maintain wake-up status at all time to control other electronic devices and monitor their on/off status whether they are in service or not. In order to reduce the unnecessary energy consumption during the standby mode, the new power-saving PLC 2 ports wall switch has been developed, separating PLC communication part and controller part and introducing sleep mode. In addition, to expand life cycle of PLC product and to reduce the rate of product failure in active mode, the instant controlling method in controlling process is adopted instead of the maintenance controlling method. In comparison to the earlier model, the new 2 ports PLC wall switch has reduced power by 0.95[W] less in standby mode and 3.2[W] less in active mode than the previous one.