• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.109-109
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• 2013

고주파 가속기의 전자선원의 설계 및 제작검증을 위한 hot-firing station을 설계하였다. 본 장치는 전자총의 빔 사이즈, 빔 전류 등을 측정할 수 있는 기기로 전원장치부, 고진공 챔버, 측정장치부 등 크게 세 부분으로 이루어져 있다. 특히 전원장치는 이중에너지 모드를 구현할 수 있도록 에너지의 크기가 다른 두개의 전자총 펄스를 생산해 낼 수 있도록 설계되었다. 고진공 챔버는 고전압 절연체를 이용하여 제작되었으며, 스크롤(건식) 펌프 와 터보 분자펌프를 이용하여 $10^{-7}$ torr 저/고진공 배기를 수행한 뒤, 이온 펌프를 이용하여 $10^{-8}$ torr까지 초고진공 배기를 수행할 수 있도록 설계하였다. 전자총으로 부터 나오는 전자들의 특성을 분석하기 위하여 패러데이 컵과 YAG 스크린을 설치하였다. 패러데이 컵은 전자빔의 인출 파형및 빔 전류를 측정하고, YAG 스크린은 CCD 카메라와 컴퓨터를 이용하여 전자빔의 균일도를 측정하여 정보를 얻도록 한다. 진공 쳄버의 최대 진공배기는 $10^{-9}$ torr이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.762-763
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• 2010

The X-ray device used for medical treatment is classified into fixed type that is used by installing at the location with the stable power supply and mobile type that can be taken by moving the X-ray device to the location where a patient is. Mobile X-ray device which is typically used in the mobile type of X-ray can be used very usefully beyond the space restriction. However, due to its difficulty to generate high-voltage, it is mainly applied to take hand and foot shootings which only need low output power. In this study, by designing and producing the large volume of mobile X-ray device which doesn't have the limitations on diagnostic areas of the body, the operating characteristics of device according to the loading change was identified.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.940-946
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• 2015

In this paper, we study a method that amplifies the output gain of a high voltage pulse using 300 kHz or higher frequency. We conducted a study on a method for amplifying the output gain using the resonance between the capacitance components of the load and the parasitic components of the circuit, instead of the conservative method for amplifying the pulse-amplitude by raising the voltage of the power stage. In particular, the method simplifies the circuit configuration throughout the appliance of flyback-type topology instead of the bridge-type. There are advantages that prevent damage from overload and the heat in the output circuit through the hard switching by amplifying the gain of the output voltage applying to the load as given by the capacitance component of the output electrode to the output pulse waveform. This study proposed a method to enhance the spatial and electrical efficiency of the contact-type heating device through the dielectric heating method applied to the field of medical and industrial heating.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.108-108
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• 2011

최근 에너지 위기와 환경 규제 강화 및 친환경, 녹색성장 등의 이슈가 대두되면서 에너지 절감과 환경보호 분야에 그린 전력반도체 수요가 날로 증가되고 있다. 이러한 그린 전력반도체는 휴대용컴퓨터, 이동통신기기, 휴대폰, 조명, 자동차, 전동자전거, LED조명 등 다양한 종류의 전력소자들이 사용되고 있으며, 전력소자의 수요증가는 IT, NT, BT 등의 융복합기술의 발달로 새로운 분야에 전력소자의 수요로 창출되고 있다. 특히 환경오염을 줄이기 위한 고전압 대전류 전력소자의 에너지 효율을 높이는 연구 개발이 활발히 진행되고 있다. 종래의 전력소자는 평면형의 LDMOS나 VDMOS 기술을 이용한 소전류 주로 제작되어 수십 암페어의 필요한 대전류용으로 사용이 불가능하다. 반면 수직형 전력소자인 트렌치를 이용한 power 소자는 집적도를 증가 시킬 수 있을 뿐만 아니라 대전류 고전압 소자 제작에 유리하다. 특히 평면형 소자에 비해 약 30%이상 칩 면적을 줄일 수 있을 뿐만 아니라 평면형에 비해 on-저항을 낮출 수 있기 때문에 수요가 날로 증가하고 있다. 트렌치 게이트 power MOS의 중요한 게이트 산화막 형성 기술은 트렌치 내부에 균일한 두께의 산화막 형성과 높은 신뢰성을 갖는 게이트 산화막 형성이 매우 중요하다. 본 연구에서는 전력소자를 제조하기 위해 트렌치 기술을 이용하여 수직형 전력소자를 제작하였다. 트렌치형 전력소자는 게이트 산화막을 균일하게 형성하는 것이 매우 중요한 기술이다. 종래의 수평형 소자 제조시 게이트 산화막 형성 후 산화막 두께가 매우 균일하게 성장되지만, 수직형 트렌치 게이트 산화막은 트렌치 내부벽의 결정구조가 다르기 때문에 $1000^{\circ}C$에서 열산화막 성장시 결정구조와 결정면에 따라 약 35% 이상 열산화막 두께가 차이가 난다. 본 연구는 이러한 문제점을 해결하기 위해 트렌치를 형성한 후 트렌치 내부의 결정구조를 변화 및 산화막의 종류와 산화막 형성 방법을 다르게 하여 균일한 게이트 산화막을 성장시켜 산화막의 두께 균일도를 향상시켰다. 그 결과 고밀도의 트렌치 게이트 셀을 제작하여 제작된 트렌치 내부에 동일한 두께의 게이트 산화막을 여러 종류로 산화막을 성장시킨 후 성장된 트렌치 내벽의 산화막의 두께 균일도와 게이트 산화막의 항복전압을 측정한 결과 약 25% 이상 높은 신뢰성을 갖는 게이트 산화막을 형성 할 수 있었다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.4
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• pp.38-46
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• 1999

Measurerments of ultrasonic signals caused by corona discharges were perforrred by using an ultrasonic meeasurerment technique to analyze the deve1qxrent states of coronas in a high-voltage power apparatus. We also examined the relationship between discharge magnitude and ultrasonic pulse number to diagnose the deterioration of electrical insulation by corona discharges. From these results, it was found that ultrasonic signals due to corona discharges can be firstly detected at the peak value of positive polarities prior to the breakdown voltages, and the magnitude of ultrasonic signals was closely related to the current pulses by the corona discharges when ac voltages were gradually raised, and it appeared that ultrasonic pulse number was proportional to discharge magnitude. Attenuation, tirre-delaying and directivity charocteristics of ultrasonic signals propagated to air by using ultrasonic oscillation and receiving systems are feJXlrt.ed as a basic data of ultrasonic measurements in out-door HV apparatus.aratus.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.339-348
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• 2017

Power supply for railway cars can be divided into propulsion system power supply and auxiliary power units (APU). The propulsion system power supply is for propulsion of railway cars, and regenerative braking; the APU provides power for the air compressor, lighting, car control and other auxiliary parts. According to high voltage and high current specifications, generally, an insulated-gate bipolar transistor (IGBT) is adopted for the switching component. For appropriate switching operation, a gate driver unit (GDU) is essentially required. In this paper, the technical trends of GDU for railway cars are analyzed and a design consideration for IGBT GDU is described.

• Journal of the Korea Convergence Society
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• v.12 no.1
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• pp.243-250
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• 2021

In the medical field, applications of plasma are applied sterilize instruments mainly but with the advent of bio-plasma technology, the scope of application is expanding. Recently, In addition, high-density miniaturization with handheld is required for sophisticated procedures when irradiated directly or treated with non-standard conditions. Rosen-type PZT is a device with a structure that generates high voltage plasma by achieving voltage transformation through electro-mechanical coupling using piezoelectric effect.and is used in portable plasma generating devices as an advantage to increase energy density relatively. In this paper, Rosen-type PZT was modeled using equivalent circuits and was carried out and a plasma generating device for medical application was designed and prototype tested. Prototype plasma generating device generates an output voltage of 5.8 kV with 12V input power and is designed to operate at high voltage by applying the half-bridge topology power converter. The results of the study confirmed the availability of various medical devices, such as plasma jets or direct exposure equipment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.154-154
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• 2009

본 연구는 고전압 전력기기인 몰드형변압기와 계기용 변성기인 CT, PT 절연특성에 유용한 Epoxy/Nano-Micro Mixture Composites(이하,ENMMC)를 개발하기위해 무엇보다 중요한 것은 Nano입자인 $SiO_2$_10nm입자의 표면을 제어하여 즉, 표면의 소수성을 크게 하여 나노입자의 균질한 분산을 얻은것이 무엇보다 중요하다. 개발된 Epoxy/$SiO_2$_10nm Nanocomposites와 Microcomposites을 기계적 전단응력을 이용하여 균질 혼합을 실시하였다. 이런 조건을 이용한 전기적특성을 측정하기위해 구대구 전극이 완전함침된 평등전계하에서 절연파괴전압을 측정하기 시편을 제조하였다. 마이크로입자의 충진함량을 일정하게 유지하여 나노입자 충진함량비율을 4가지로 변화시켜 절연파괴특성을 연구하였다. 충진함량이 나노입자의 경우 1wt%이하의 값이 상대적으로 우수한 절연파괴특성으로 와이블 플롯을 통하여 알수있었다. 상대적으로 멀티나노콤포지트의 형상파라미터가 큰 결과값을 얻을수 있었다. 그리고 스케일파리미터는 누적확률 밀도함수로서 63.2%에서 대단히 큰 초절연성의 절연소재를 개발할수 있었다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.12
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• pp.624-630
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• 2001

The trend of the regulations on environmental issues are getting tight. Responding to this trend new technologies such as moving electrodes, wide pitch and pulsed power supply are also introduced in the electrostatic precipitator(EP) systems. The introduction of wide pitch and moving electrodes enhances the system performance of the EPs by improving air-flow and by improving the ash reentrainment on rapping. The power supplies for the EPs developed up to date include thyristor-based dc or intermittent type, SMPS(switching mode power supply) type and the pulsed-power supply type. The use of the pulsed ones is known to improve dust-collecting efficiency of high resistivity ash and reduces back corona occurrence in the collecting plate. There are two kinds of pulsed-power supplies; one with pulsed transformers and the other with direct dc switching devices. The latter uses rotary spark gap switches or semiconductor switches. Both have the merits and demerits: the spark gap switches are simple and robust but has short life time, hence, high maintenance cost, whereas the semiconductor switches have long life time but are costly. In this study, A high voltage power supply with superimposing voltage pulse on dc source was developed for EPs. This study describes circuit topology, operating principle of the scheme, and analysis of experimental results on Dong-Hae Power Plant. The pulsed power supply consists of a variable dc power supply with ratings of 60kV, 800mA and pulse generator which is made of high voltage thyristor-diode switch strings, an LC resonant tank and a blocking inductor. The pulse generator generates variable pulse-voltage up to 70kV using a high frequency resonant inverter with a variable dc source. Two prototypes were built and tested on 250MW DongHae power plant to verify the possibility of the commercial use and the normal operation in the transient states.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.356-360
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• 2014

The environmental pollution caused by green-house gases such as $SF_2$ has been becoming the main issue of industrial society. As a part of these efforts, 180 countries signed the Kyoto Protocol in 1997 to cut back on their green-house gas emissions [1]. Therefore, a study on the dielectric characteristics of the $GN_2$ is important for designing a eco-friendly high voltage apparatuses. In this paper, to develop an electrically reliable, stable, and eco-friendly high voltage apparatus, the breakdown voltage and partial discharge inception voltage characteristics in $GN_2$ considering utilization factors are studied for the establishment of insulation design criteria of an high voltage apparatus. Dielectric experiments are performed by using several kinds of sphere-plane electrode systems made of stainless steel. Also, the dielectric characteristics of the $GN_2$ are analyzed by using a Finite Elements Method (FEM) according to various field utilization factors. The results are expected to be applicable to designing the high voltage apparatuses using $GN_2$ as an insulation gas.