• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.200-201
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• 2005

This paper is analyzed a new modulation method of OSW(Optimized Sine-Wave) modulation strategy for cascaded H-bridge multi-level inverter. The inverter structure was modified with the maximum output voltage level, and the switching angle was calculated easily to adjust the requested Vrms of the output. The suggested modulation method could make output waveform very close to the ideal sine wave, and the THD value was improved also remarkably.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1119-1124
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• 2014

본 논문은 석유시추선의 전력 계통 시스템의 비상시 전력 계통 해석에 대하여 기술하였다. 특히 석유시추선의 추진부하와 발전기의 탈락으로 인해 발생하는 전력계통 시스템에 미치는 영향을 검토하였다. 또한 고정 여자방식과 조속기의 제어 변수를 조정하여 임의의 사고 전후 정상상태로의 복귀까지 과도 안정도 해석으로 전력계통에 나타나는 현상을 관찰하였다. 전력계통 설계와 해석 및 과도 현상해석 프로그램인 ETAP(Electrical Transient Analysis Program)을 사용하였으며, 수치해석의 결과를 도출하여 그 특성을 분석하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제40권5호
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• pp.429-436
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• 2016

Currently, many studies on green ships are under way. Fuel cell (FC) ships are of interest as future low-emission, fuel-efficient vessels. In this paper, a hybrid power management system for an FC ship was designed. The system consists of an FC, a battery, a unidirectional DC/DC converter, a bidirectional DC/DC converter, a filter, an inverter, and a propulsion component. To design the system, we analyze electric sources and converters, and create PLECS models of hybrid power management system. Then, we check the cold start sequence and perform a simulation to understand the characteristics of the hybrid power management system in an FC ship.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.150-155
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• 2013

A high voltage and nanosecond Blumlein pulse generator has been developed to produce an output pulse whose voltage level is greater than 250 kV and pulse duration 5 ns. The generator consists of various components such as a charging circuit, a pulse transformer, and a spark gap switch. As a heart of the generator, a Blumlein pulse forming line has been constructed in the cylindrical form using three cylindrical aluminum electrodes that are placed concentrically. Unlike the ideal Blumlein line, the output pulse of an actual Blumlein line may be affected by stray inductances and capacitances of switching and charging components, thereby degrading the performance of the generator. In this paper, PSPICE simulations have been performed to examine effects of stray inductances and capacitances on waveforms of output pulses. Simulation results show that the pulse waveform is significantly distorted mainly by the stray inductance of the spark gap switch.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.886-887
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• 2015

선진 각국에서는 고효율, 친환경 에너지 공급 및 이용 기술, 그리고 효율적인 에너지 절약 기술 개발에 관한 연구 개발이 활발히 진행되고 있다. 이러한 연구 중 항공기 분야에서는 전동기로 프로펠러를 회전시키는 전기추진 항공기에 대한 관심과 수요가 증가하고 있다. 소형 항공기 추진용 전동기는 엔진과 함께 소형 항공기의 주 구동원으로서 중요성이 강조되고 있다. 또한 근래에 전동기의 비중이 커짐에 따라 고출력, 고효율화 되고 있는 추세이다. 본 논문에서는 항공 운항 패턴 중 이륙, 상승, 순항구간에 따라 각각 요구하는 성능을 만족하는 고출력, 고효율 전동기 개발에 대해 다루었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.888-889
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• 2015

세계적으로 석유 연료를 대체할 에너지원인 전기에너지에 대한 관심이 높아지고 있고, 전기자동차 뿐만 아니라 항공기에 사용할 고출력 전동기에 관한 연구 및 개발이 진행되고 있다. 고출력 밀도를 갖는 전동기의 경우 방열설계가 잘되어 있지 않으면, 발열로 인한 전동기의 성능과 내구성 및 수명이 단축되게 된다. 본 논문에서는 소형 항공기의 이륙, 상승, 순항구간에 요구되는 출력특성을 만족하도록 설계된 전동기에 대해, 항공 운항 Mission Profile의 출력 및 시간변동에 따른 온도 특성을 분석해 보았다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.876-879
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• 2003

본 논문은 전동차용 추진제어장치의 재점착제어에 관한 것이다. 본 연구에서는 공전검지 방법에 대하여 기술하고, 등가 관성량을 이용한 추정재점착제어에 관하여 제시한다. 서울시 6호선 국산화 전동차(609편성)와 광주도시철도 1호선 전동차에 적용하여 재점착 제어성의 우수함과 안정성을 검증 하고자 한다.

• Journal of Power Electronics
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• 제11권4호
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• pp.612-619
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• 2011

This paper presents a water treatment system for leachate from sewage-filled ground that uses a pulsed-power modulator developed based on semiconductor switches in order to realize a long life, a high repetition rate, and a fast rising time. The specifications of the developed pulsed-power modulator are the pulsed output voltage, the output current, the pulse repetition rate (PRR), the pulse width, and an average output power of $60\;kV_{max}$, $300\;A_{max}$, 3000, $50\;{\mu}s$, and 15 kW, respectively. The pulsed-power water treatment system was introduced and analyzed using an equivalent electrical circuit model to optimize the output voltage waveform. The experimental results verify that the proposed water treatment system can be effectively used for industrial applications.

• 기술혁신학회지
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• 제6권4호
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• pp.462-479
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• 2003

The policy trends of use and the development of nuclear power in the United States, France, United Kingdom. Germany, Russia, China, Japan and Korea are briefly investigated. Nuclear power technology has been developed as the national policy in the nuclear-advanced countries. 50 years has passed since the declaration of "Atoms for Peace" by USA President Eisenhour in December 1953. Recently, it appears to revitalize the nuclear power program in world major countries in order to recover the shortage of electric power and to curb the excess emission of carbon dioxide as well as to secure competitiveness in electricity markets. Advanced countries are making new initiatives for the development of the fourth generation nuclear power system. Furthermore, wide-ranged use and development of nuclear power technologies are expected in district heating in commercial sectors, power in the space exploration, and propulsion power of large tankers and spaceships. High temperature gas cooled nuclear power reactor will be applied for mass production of hydrogen energy in the future.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.555-558
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• 2013

A type of electric propulsion employed by specialized purpose vessels or offshore is the azimuth thruster. Azimuth thruster application had been increasing recently and resulted to excellent vessel maneuverability. However, this system is very complex and some of its major component being exposed under the seawater level presents difficulty in sealing design. For Polar class icebreaker operating in extreme sea condition, this requires a high level of reliability and safety. In this study, the characteristics of lubricating orifice pipe structural vibration installed at the lower reduction gear were investigated and analyzed through beam analysis theory and comparison of experiments. Propeller excitation and the resonant modes of vibration causing excessive vibration and suitable countermeasures to prevent damage due to vibration fatigue on the pipe are presented.