• 전력전자학회논문지
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• 제9권2호
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• pp.187-193
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• 2004

PDA, 스마트폰, USP 및 전기자동차와 같은 전기적 장치의 전력공급을 위하여 배터리가 직렬로 연결된 다중 셀을 만들어 일반적으로 사용한다. 이 경우 개별 셀 전압의 편차가 발생되면 배터리의 수명과 용량은 낮아지게 된다. 셀에서 전압의 안정화상태를 유지하기 위한 셀 전압을 안정화시키는 효율적인 방범은 없어서는 안 될 중요한 사항이다. 본 논문에서는 휴대형 가전기기에 적용하기 위해 마이크로컨트롤러를 사용한 다중 셀용 밸런싱 회로의 설계에 대하여 제안한다. 밸런싱 시스템은 충전되는 주기 동안 밸런싱 동작을 이행하며 마이크로컨트롤러로서 제어된다. 제안된 방법은 충전기와 레코드를 사용하여 실험을 통해 증명하였다. 실험결과에서 개별 배터리의 용량, 수령, 성능이 향상됨을 보여준다.

• 한국전자파학회논문지
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• 제30권4호
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• pp.286-289
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• 2019

본 논문에서는 다중 입 출력 무선전력전송 시스템의 최대 전송 효율 구현을 위한 송신기 입력 및 수신기 부하 제어방법을 제안하였다. 최대 전송 효율 구현에 필요한 각 송신기의 입력전압과 수신기의 부하를 송수신기 간의 성능지수를 이용하여 유도하였다. 유도한 최적 입력전압과 최적 부하는 적절한 예시를 통해 Genetic algorithm을 이용해 최적화한 결과나 회로 시뮬레이션 결과와 유사함을 확인하였다. 본 논문에서 제시된 이론적 방법을 적절히 활용한다면, 근거리 다중 입 출력 무선전력전송 시스템의 효과적인 설계가 가능할 것이다.

• 한국공간구조학회논문집
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• 제16권3호
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• pp.79-88
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• 2016

An outrigger damper system has been proposed to reduce dynamic responses of tall buildings. In previous studies, an outrigger damper system was optimally designed to decrease a wind-induced or earthquake-induced dynamic response. When an outrigger damper system is optimally designed for wind excitation, its control performance for seismic excitation deteriorates. Therefore, a smart outrigger damper system is proposed in this study to make a control system that can simultaneously reduce both wind and seismic responses. A smart outrigger system is made up of MR (Magnetorheological) dampers. A fuzzy logic control algorithm (FLC) was used to generate command voltages sent for smart outrigger damper system and the FLC was optimized by genetic algorithm. This study shows that the smart outrigger system can provide good control performance for reduction of both wind and earthquake responses compared to the general outrigger system.

• 대한전기학회논문지
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• 제34권1호
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• pp.19-28
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• 1985

As is well known, the power equations of the N-node system have 2N-1 voltage solutions at most. The vlotage solutions are characterized by the introduction of the mode concept in this paper. There are two mode voltages at one node. One is defined as the (+) mode voltage and the other is defined as the (-) mode one. In this paper, we show that the (-) mode voltage responds to the increase of the power condenser almost adversly to the response of the (+) one. We study how to prevent the voltage collapse in the system with the induction motor load. The critical values of the gain and the time constant in case of the continuous power condenser control, and of the unit power condenser and the closing time delay in case of the discontinuous control for the prevention of the voltage collapse, are calculated. The effect of the composition ratio of the impedance load to the induction moter load on the above critical values are also investigated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.107-111
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• 1996

In this paper, the voltage monitoring system is designed to monitor the outage and voltage fluctuation by using a dial-up telephone. The master station receives tire outage signal-such as interruption and voltage sag etc. - from the remote in on-line of real-time. The SCC(Serial Communication Controller) is adapted to monitor voltages multiple clients(about 256 clients) simultaneously. The voltage fluctuation in a normal range shall be transmitted to the master station, at early morning the clients use the telephone less frequently. The operating system shall be "window 95" and the database is programmed in Visual-basic for a easy analysis of voltage fluctuation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.737-742
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• 2002

The chief factors for the penetration and diffusion of chloride ions in concrete are water-cement ratio(w/c), aging, thickness of cover concrete, chloride ions concentration of given environment, wet and dry conditions and etc. In this study, effect of w/c and aging on the characteristics of chloride ions diffusion in concrete were researched when environmental factors for the penetration and diffusion of chloride ions were constant. For this purpose, the voltages passing through the diffusion cell were measured by using accelerated test method using potential difference, and then diffusion coefficients of chloride ions by using Andrade's method were estimated for 44%, 49.5% and 55% of w/c, respectively. As a result, correlation among diffusion coefficients of chloride ions, w/c and aging were concluded through multiple regression model.

• 조명전기설비학회논문지
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• 제16권2호
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• pp.38-44
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• 2002

전력변환기와 같은 비선형 부하의 사용증가는 전력시스템에 고조파를 발생시킨다. 고조파를 포함하는 전류와 전압은 전기설비에 고장과 오동작을 일으키게된다. 위상조정 변압기는 고조파 발생원이 병렬로 설치되어 있는 곳에 설치하면 고조파 문제를 효과적으로 해결할 수 있다. 본 논문에서는 EDSA고조파 분석 프로그램을 사용하여 고조파를 제거하기 위한 위상조정 변압기의 효과를 분석하고 검증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권12호
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• pp.602-607
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• 2003

We show three-dimensional distribution of voltages resulted from the leakage current originated from outdoor electrical facilities in a submerged area. In case these facilities are grounded by the neutral line multiple grounding method, the existence of ungrounded electrical facilities can cause a disastrous effect on near-by passengers. In order to investigate this situation, we installed a real-scale test field for the experiment type I (for the leakage current path between a enclosure grounded electrical facility and another enclosure grounded one), and that for the experiment type II (for the leakage current path between a enclosure grounded electrical facility and another ungrounded one). For both cases, we carried out three-dimensional monitoring of the voltage distribution while varying additional conditions such as the exposure of the underground cables and the finishing of cable connection part. The result shows that a disastrous effect on human safety can arise from the leakage current without a pertinent measure for the construction and maintenance of outdoor electrical facilities.

• Journal of Power Electronics
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• 제10권3호
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• pp.245-250
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• 2010

Input-series-output-parallel (ISOP) converters consisting of multiple modular DC/DC converters can enable low voltage rating switches to be used under high voltage input applications. This paper presents a digital control strategy, which can achieve equal sharing of input voltage for a modular ISOP system consisting of two-transistor forward DC/DC converters by forcing the input voltages of neighboring modules to be equal. The proposed scheme is analyzed using small signals analysis based on the state space average method. The performance of the proposed control strategy is verified with an experimental prototype of an ISOP converter made up of three two-switch forward converters.

• E2M - 전기 전자와 첨단 소재
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• 제7권2호
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• pp.152-156
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• 1994

The rapid thermal annealing effects of Sol-Gel derived ferroelectric PZT thin films were investigated. It was found that rapid thermal annealing(RTA) of spin coated thin films on silicon typically >$800^{\circ}C$ for about 1 min. was changed to the perovskite phase. Rapid thermally annealed films recorded maximum remanent polarization of about 5 .mu.C/cm$^{2}$, coercive field of around 30kV/cm. The switching time for polarization reversal was about 220ns. The films of RTA process showed smooth surface, and high breakdown voltages of over 1 MV/cm and resistivity of $1{\times}{10^12}$ .ohm.cm at 1 MV/cm. It was verified that the polarization reversal of the PZT film was varied partially with applying the multiple short pulse.