• International Journal of Reliability and Applications
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• 제7권2호
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• pp.89-99
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• 2006

A new classes of life distribution, namely harmonic used better than aged in expectation in upper tail (HUBAEUT) is introduced. Testing exponentiality against this class is investigated using kernel method. The limiting null and nonnull distribution of the test statistics is normal and the null variance is calculated exactly. Selected critical values are tabulated for sample sizes of 5(1)40. Power of the test are estimated by simulation. the efficacies of the test statistics used for testing against HUBAEUT are calculated for som common alternatives and are compared to some other procedures. It is shown that proposed test is simple, has high relative efficiency and power for some commonly used alternatives. The set of real data are used as an examples to elucidate the use of the proposed test statistics for practical reliability.

• 전기전자학회논문지
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• 제13권4호
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• pp.82-88
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• 2009

본 논문에서는 새로운 고효율의 절연형 스텝 업-다운 DC/DC 초퍼에 대해 해석하였다. 일반적으로 고효율의 초퍼를 만들기 위해서는 전력변환기내에 사용된 반도체 스위칭 소자의 손실이 최소화 되어야 한다. 본 논문에서는 부분공진 회로를 초퍼에 추가하여 고효율을 실현시킨다. 제안한 초퍼에 사용된 제어용 스위칭 소자들은 부분공진기법에 의해 소프트 스위칭으로 동작하고, 이에 따른 제어용 스위칭 소자들은 전압과 전류의 스트레스 없이 동작한다. 그 결과 제안한 초퍼는 스위칭 손실의 저감에 의해 고효율로 구동한다. 그리고 제안한 초퍼는 펄스 변압기를 이용하여 입력단과 출력단을 절연시켜, 전기적 절연이 요구되는 전력변환기들에 적용되어 고효율의 전력변환시스템을 개발할 수 있는 장점이 부여된다. 제안한 절연형 스텝 업-다운 초퍼의 소프트 스위칭 동작과 시스템 효율은 다양한 시뮬레이션과 실험결과를 통해 그 타당성이 입증된다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.203-205
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.387-390
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit Incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• 한국항행학회논문지
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• 제22권4호
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• pp.319-324
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• 2018

본 논문은 RF 전력 반도체를 사용한 고출력 전력증폭기를 구현한 것으로 기존의 플라즈마 발생 장치에 사용되는 마그네트론 방식의 고출력 증폭기 문제점인 낮은 효율과 짧은 수명, 유지 보수의 어려움 그리고 높은 운용비용 등을 개선하기 위한 것이다. 구현된 고출력 전력증폭기는 2.45 GHz ISM (industrial scientific medical) 대역에서 공간 결합방식을 이용한 저 손실, 고출력 레디알 결합기와 반도체로 3 kW급 출력을 얻기 위해서 300 W 급 전력 증폭기 16개의 증폭기로 구성되어 있다. 또한, 이 증폭기는 개별적인 증폭기에 수냉 방식의 구조를 적용하여 고출력에 따른 발열문제를 극복하였다. 소형 시스템으로 구성된 이 전력증폭기는 원하는 출력에서 50%의 높은 효율을 얻었다.

• International journal of advanced smart convergence
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• 제9권2호
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• pp.105-113
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• 2020

In this paper, we proposed a soft switched synchronous boost converter, which can perform discharging the battery, is proposed. The proposed converter has low switching loss even at high frequency operation due to its soft switching characteristics. The converter operates in synchronous mode to minimize conduction loss because of changing the rectified diode to MOSFET with a low on resistance. In this reason, the efficiency of the converter can be greatly improved in high frequency. In this paper, the battery discharger with a switching frequency of 100 kHz, has been designed. The designed converter also simulated to prove the converter's characteristics of synchronous operation as well as soft switching operation. The simulation shows that the proposed converter always meets the soft switching conditions of turning on and off switching in the zero voltage and zero current states. Therefore, simulation results have confirmed that the proposed battery discharge had soft switching characteristics. The simulation results have confirmed that the proposed battery discharger had soft switching and synchronous operation characteristics.

• 산업기술연구
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• 제19권
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• pp.217-226
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• 1999

A single phase to three phase power converter with cost effective and simple structure is proposed. The converter consists of rectifier and inverter. The rectifier is composed of a half wave rectifier, a dc link capacitor, and a current limiting inductor, and the inverter is of only two switches with PWM control. For negative sequence operation the inverter output voltage leads the line input by $60^{\circ}$, and for positive sequence operation the inverter output voltage leads by $60^{\circ}$. We can see that positive sequence operation shows higher output voltage, slight harmonic distortion(2%), and better performances such as high efficiency and high power factor. A mathematical model for system analysis is provided, and specifications for selection and control scheme both for start-up and for steady state are analyzed. comparison and operational limits of positive and negative sequence operation are performed, and simulations and experiments are executed to verify the proposed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.969-972
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• 2003

This paper deal with a necessary factors for design grid connected photovoltaic system with stand-alone operation, and show simulation results of individual functions and multi- operation according to utility condition. Generally, photovoltaic system have only one operation of either stand-alone or line interactive, and have a isolation transformer for electrical isolation from utility therefore it is bulky, weighty, and a high price system as compared with usefulness. In this paper, A topology and algorithm adequate for lightweight, high efficiency, low price, multi function is selected and inquired into the validity using simulation of variable conditions.

• 전기학회논문지
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• 제65권1호
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• pp.73-80
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• 2016

The preliminary test for the dual mode plasma torch system was carried out to explore the operation properties in advance. The dual mode plasma torch system that is able to operate in transferred, non-transferred, or dual mode is very adequate for melting the mixed wastes including nonconductive materials such as concrete, asbestos, etc. since it exploits both the high efficiency of heat transfer to the melt in transferred mode and stable operation in non-transferred mode. Also, system operation including restarting is reliable and very easy. A stationary melter with a refractory structure was designed and manufactured considering the melting behavior of slags to minimize the refractory erosion. The power supply for the dual mode plasma torch system built with high power insulated gate bipolar transistor (IGBT) modules has functions for both current control and voltage control and is sufficient to suppress the harmonics during the operation of the plasma torch. The power supply provides two different voltages for transferred operation and non-transferred. It is confirmed that the operation voltage in transferred is always higher than non-transferred. The dual mode plasma torch system was successfully developed and is under operation for a melting experiment to optimize operation data.

• 부동산연구
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• 제28권3호
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• pp.37-52
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• 2018

이 연구는 산업단지의 효율적 운영 방안 마련의 기초연구로 우리나라 산업단지의 상대적 효율성 수준을 측정하고, 다양한 유형별 차이를 분석하는데 목적이 있다. 이를 위해서 2017년 기준 287개의 산업단지의 생산액과 수출액을 산출변수로, 산업용지면적과 종사자수를 투입변수로 자료포락분석(Data Envelopment Analysis; DEA)을 적용하였다. 분석결과, 우리나라 산업단지의 상대적 효율성은 주로 단지유형과 운영기간에 따라 영향을 받는 것으로 분석되었다. 단지유형 측면에서는 도시첨단산업단지가 가장 높게 나타났으며, 다음으로 국가산업단지, 일반산업단지의 순으로 분석되었다. 따라서 산업단지의 효율성을 확보하기 위해서는 산업단지 업종의 첨단화와 물리적 규모의 확대가 필요할 것으로 판단된다. 또한 산업단지 운영기간이 증가함에 따라 산업단지의 상대적 효율성이 높아지고 있고, 노후산업단지의 상대적 효율성이 그렇지 않은 산업단지에 비해 높게 분석되었다. 이러한 결과는 효율성이 확보된 노후산업단지의 경우 재생의 효과가 극대화될 수 있기 때문에 노후산업단지의 재생사업 우선순위 선정에 있어 하나의 고려요소로 적용할 수 있을 것이라 판단된다.