• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.341-342
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• 2015

Attention has been focused on how to charge an electric vehicle in accordance with the increase of interest in the electric vehicle in recent years. The charging of an electric vehicle with a solar power is way to increase the stability of the grid and to supplement the grid power demand. In this paper, the EMTP / ATPDraw presents a method of charging an electric vehicle in connection to the grid and the solar power system, and analyze the trends in supply power from the solar power system according to changes in temperature and irradiation.

• 전기학회논문지
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• 제66권1호
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• pp.55-60
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• 2017

Capacitor Charging Power Supply(CCPS) is one of the most important components of a pulsed power system. The CCPS is widely used in source of lasers, accelerators and plasma generators. This paper presents design of a dead time control circuit and operation characteristics for stable high repetition rate of high voltage CCPS. The CCPS consists of battery, high voltage transformer and controller with a dead time control circuit. A dead time control circuit was simulated by PSpice. The performance test of the CCPS was carried out with a 7[nF] load capacitor at output voltage of 50[kV] and a pulse repetition frequency of 100[Hz]. As a result, we can verify that charging and discharging waveform is stable at 100[Hz]. The experiment results indicate that 3[ms] dead time made it possible for stable high repetition rate of 100[Hz]. This paper paves the way for designing an advanced CCPS which is more applicable outside experiments.

• Journal of Power Electronics
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• 제17권4호
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• pp.1109-1116
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• 2017

Wireless power transfer (WPT) technology has the advantages of intelligence and facilitation. This paper designs a WPT system applied to battery charging and provides a strategy which switches from the constant current (CC) charging mode to constant voltage (CV) charging mode. The LCL-LCL topology is used to realize the CC output, while the LCL-S (series compensation) topology is used to realize the CV output. The main factor affecting the output characteristics is extracted by analyzing the two topologies above. Based on the main factor, this paper puts forward a modified way to design the system. In addition, on-line monitors for the battery and switches are placed at receiving side, which avoids the need for introducing an information interaction module into the system. Therefore, the complexity of the controlling system is reduced. Finally, simulation and experimental analyses are carried out to verify the correctness of the compound topologies.

• 산업기술연구
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• 제40권1호
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• pp.7-12
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• 2020

Lithium-ion cells have become the go-to energy source across all applications; however, dendritic growth remains an issue to tackle. While there have been various research conducted and possible solutions offered, there is yet to be one that efficiently rules out the problem without, however, introducing another. This paper seeks to present a fast charging method and system to which lithium-ion batteries are charged while maintaining their lifetime. In the proposed method, various lithium cells are charged under multiple profiles. The parameters of charge profiles that inflict damage to the cell's electrodes are obtained and used as thresholds. Thus, during charging, voltage, current, and temperature are actively controlled under these thresholds. In this way, dendrite formation suppressed charging is achieved, and battery life is maintained. The fast-charging system designed, comprises of a 1.5kW charger, an inbuilt 600W battery pack, and an intelligent BMS with cell balancing technology. The system was also designed to respond to the aging of the battery to provide adequate threshold values. Among other tests conducted by KCTL, the cycle test result showed a capacity drop of only 0.68% after 500 cycles, thereby proving the life maintaining capability of the proposed method and system.

• 한국재난정보학회 논문집
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• 제19권2호
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• pp.411-420
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• 2023

연구목적: 수소충전소의 위험성 평가의 한계를 보완하고자 운영중 발생 가능한 사고에 대한 안전성 및 사업연속성을 강화하기 위한 방안으로 기업재해경감활동을 적용을 제안한다. 연구방법: 수소충전소 설치 및 운영의 시간 흐름에 따라 위험을 구분하고, 핵심업무를 식별, 위험시나리오를 도출하여 이를 분석, 평가, 처리하는 과정을 통해 위험을 경감, 제거,전가, 수용할 수 있는 기업재해경감활동의 일부적용을 탐구해 보았다. 연구결과:수소충전소 설치전 단계에 시행하고 있는 위험평가는 기존의 연구 결과가 적절히 적용되고 있다. 그러나 운영단계에서 발생 가능한 위험에 대해서는 한계가 있어 몇 가지 예시 시나리오를 가지고 기업재해경감활동을 적용해 보니 안전성과 사업연속성 강화 방안으로 적용이 가능하다는 결과를 도출하였다. 결론:현재 시행중인 수소충전소 위험성평가는 모두 적절하게 활용되고 있다. 그러나 운영단계에서 발생 가능한 위험에 대한 평가와 대응방안으로 다양한 위험시나리오를 적용하는 기업재해 경감활동을 제안한다.

• 한국의료질향상학회지
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• 제4권1호
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• pp.116-124
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• 1997

Background : As parking problem caused by increasing owner-driver and patients concentrating to a general hospital is becoming one of the dissatisfactions in medical care. It is time that a general hospital should solve the parking problem in a desirable way. The purpose of this survey is to let the clients understand the basic motivation of the pay parking and develop the better parking system. Methods : Clients of a tertiary care hospital in Chon-ju were surveyed by means of a questionnaire. All in all, 193 subjects answered the questionnaire. Results : In relation to previous experiences, 39.6% of the subjects experienced inconvenience with confused parking lot and the shortage of parking space. Under the current parking system, the subjects who felt the available parking space was enough were more than those who didn't 62.7% of the subjects answered that they could find the parking lot easily. 33.2% of the subjects mentioned that it was not easy to drive in the parking area ; The reasons were pointed out the shortage of space, disordered parking, and insufficient guide. 12.8% of the subjects satisfied with the current administering system of parking lot. The outpatients were more affirmative than the admitted patients about the charging system. As for the parking fee, 64% of the subjects answered that it is expensive, and 89.5% of the subjects thought imposing of parking fee is irrational. Conclusion : To say as a whole, the basic purpose of the charging system are more or less accepted. However, the management details like parking facilities and payment method are dissatisfactory, so it is necessary to improve the management system. It is also noted that the inpatients showed more negative attitude than the outpatients with the charging system. To secure a more convenient parking, the parking system should be considered in relation to the information service, kind guidance, improve facilities, personnel cooperation, fix outpatient scheduling system, etc.

• 디지털융복합연구
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• 제11권7호
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• pp.141-148
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• 2013

스마트그리드는 정보통신기술을 이용하여 전력공급자와 소비자의 양방향통신을 가능하게 한다. 또한 동적인 전력 공급이 가능하기 때문에 전기 자동차 기술과 접목시킬 경우 전기 자동차 충전 인프라를 활성화시키고 전기 자동차의 배터리를 가정용 축전지로 활용하여 재판매할 수도 있다. 이러한 전기 자동차 충전 인프라는 가정, 아파트, 건물, 기타 충전소 등에 고정적으로 위치하여 있고 사용자만 유동적으로 서비스를 이용한다. 만약 유동적으로 서비스를 이용하는 사용자에 대해 인증이 이루어지지 않을 경우 전력 서비스의 불법적인 사용, 전력 정보 유출, 불법적인 전력 요금 변경 등의 피해가 발생할 수 있다. 본 논문에서는 스마트그리드 환경에서 안전하게 전기 자동차 관련 서비스를 이용하기 위해 스마트카드 및 동적 ID 기반 사용자 인증 스킴을 제안한다.

• International Journal of Internet, Broadcasting and Communication
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• 제14권1호
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• pp.194-200
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• 2022

As of 2020, the cumulative number of electric vehicles worldwide increased 43% from 2019, exceeding 10 million. We surveyed and analyzed important factors when purchasing electric vehicles for consumers who own electric vehicles. Through this, we tried to find an effective way to supply electric vehicles in the future. The purpose of this study is to present customized marketing proposals for companies by empirically analyzing the factors affecting consumers' electric vehicle purchases and deriving market demands for electric vehicles. We identified the market status of electric vehicles through literature research and reviewed previous studies on the factors affecting the purchase intention of electric vehicles. Through empirical studies, differences in electric vehicle purchase factors according to gender, age, and the degree of importance of performance were analyzed. To this end, the SPSS statistics package was used. Factors influencing the purchase of electric vehicles were set to mileage, charging time, new technology, degree of driving autonomous development, design, price, infrastructure for charging, the phase of maintenance and repair, by the government and local governments. In addition, the most important factors were derived, and the average difference analysis was conducted according to gender, age, and performance importance.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 추계학술대회
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• pp.42-44
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• 2018

An integrated charger is used for bi-directional power conversion between an electric vehicle and a power grid. The proposed integrated charger works in a way that motor windings are utilized as filter inductances for charging/discharging of batteries in addition to the original purpose of motor drives. After a mathematical model of the integrated charger based on an dual winding induction machine (DWIM) is discussed, a current control method is designed for grid connection. The effectiveness of the proposed method is examined with simulation results.

• International Journal of Aeronautical and Space Sciences
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• 제16권2호
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• pp.247-253
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• 2015

The components of an aero-engine gas path cannot be monitored in a timely way due to a lack of real-time monitoring technologies. As an attempt to address this problem, we have conducted research on a condition monitoring technology based on the charging characteristics of particles in an aero-engine gas path, and emphatically analyze the formation of particles in an aero-engine gas path, the charging mechanism of carbon particles and the factors that influence the charge quantity and polarity. The verification experiments are performed on the simulated experiment platform and a turbo-shaft engine test bench. The results show the carbon particles' carry charge, and an obvious change in the total electrostatic charge level in the aero-engine gas path due to the increased carbon particles produced by burning or abnormal metal particles; the charge number is related to the size of particles, and the bigger carbon particles carry a negative charge and metal particles carry a positive charge; the change in engine power can lead to an obvious change in the level of electrostatic charge in the gas path, and the change in electrostatic charge results from the extra carbon particles formed in the rich-oil burning process. The research provides a reference for establishing the baseline of electrostatic charge while the engine runs on different power. The study also demonstrates the validity of the electrostatic monitoring technology and establishes a base for developing the application of electrostatic monitoring technology in aero-engines.