• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.956-959
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• 1996

In this study, we propose a neuro-genetic controller combined with a linear controller in parallel to improve the tracking performance of the Line of Sight(LOS) stabilization system and reject the effect of disturbances. A Genetic Algorithm(GA) is used to optimize weights of the neuro-genetic controller since this algorithm can search a global minimum without derivatives or other auxiliary knowledge. The LOS system is very complex and has limited measurable output data. Under these specific circumstances GA solves many problems that other training methods have. Computer simulation results show that the, proposed controller makes better tracking response and rejection of disturbance than a linear controller.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.188-191
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• 2002

This paper presents a method for on-line estimation of rotor time constant of induction motor. The proposed method applies a model reference adaptive system(MRAS) using rotor flux vector. The MRAS consists of two independent observers to estimate the rotor flux vector; one based on voltage equations of rotor flux vector, the other based on current equations of them. The MRAS utilizes concept of auxiliary variables to normalize observer output and decrease high-frequency components of its input. Experimental results verify the validity and usefulness of proposed method

• Journal of Power Electronics
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• 제9권4호
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• pp.593-603
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• 2009

This paper proposes and describes the design and operational principles of a three-phase three-level nine switch voltage source inverter. The proposed topology consists of three bi-directional switches inserted between the source and the full-bridge power switches of the classical three-phase inverter. As a result, a three-level output voltage waveform and a significant suppression of load harmonics contents are obtained at the inverter output. The harmonics content of the proposed multilevel inverter can be reduced by half compared with two-level inverters. A Fourier analysis of the output waveform is performed and the design is optimized to obtain the minimum total harmonic distortion. The full-bridge power switches of the classical three-phase inverter operate at the line frequency of 50Hz, while the auxiliary circuit switches operate at twice the line frequency. To validate the proposed topology, both simulation and analysis have been performed. In addition, a prototype has been designed, implemented and tested. Selected simulation and experimental results have been provided.

• 전기전자학회논문지
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• 제14권1호
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• pp.1-7
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• 2010

본 논문은 디스플레이포트 v1.1a 표준에 적합한 AUX(Auxiliary) 채널 구현에 대한 논문이다. 디스플레이포트는 영상 및 음성을 전달하기 하기 위해 메인 링크, AUX 채널, 핫 플러그 검출 라인을 사용한다. 등시적 전송 서비스를 제공하기 위해서 소스 디바이스는 메인 링크를 통해 전달될 영상 및 음성 신호를 특정 형태로 변환하여 재구성하고 싱크 디바이스로 전달한다. AUX 채널은 메인 링크를 구성하고 유지하기 위해 링크 서비스를 제공한다. 그리고 디스플레이 장치가 소스 디바이스에서 전송된 데이터를 정상적으로 나타낼 수 있는지 파악하기 위해 디바이스 서비스를 제공한다. 핫 플러그 검출 라인은 두 디바이스간의 연결을 확인하기 위해서 사용한다. 본 논문은 AUX 채널 구현을 목표로 설계하였으며 설계된 시스템은 SoC Master3를 이용하여 검증을 수행하였다. 합성 툴은 Xilinx ISE 9.2i를 사용하여 3315개의 LUTs와 1466개의 Flip Flops을 사용하였고 최대 168.782MHz 동작 속도의 결과를 얻었다.

• Nuclear Engineering and Technology
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• 제44권6호
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• pp.597-610
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• 2012

The passive auxiliary feedwater system (PAFS) is one of the advanced safety features adopted in the APR+, which is intended to completely replace the conventional active auxiliary feedwater system. With an aim of validating the cooling and operational performance of PAFS, an experimental program is in progress at KAERI, which is composed of two kinds of tests; the separate effect test and the integral effect test. The separate effect test, PASCAL ($\underline{P}$AF$\underline{S}$ $\underline{C}$ondensing Heat Removal $\underline{A}$ssessment $\underline{L}$oop), is being performed to experimentally investigate the condensation heat transfer and natural convection phenomena in PAFS. A single, nearly-horizontal U-tube, whose dimensions are the same as the prototypic U-tube of the APR+ PAFS, is simulated in the PASCAL test. The PASCAL experimental result showed that the present design of PAFS satisfied the heat removal requirement for cooling down the reactor core during the anticipated accident transients. The integral effect test is in progress to confirm the operational performance of PAFS, coupled with the reactor coolant systems using the ATLAS facility. As the first integral effect test, an FLB (feedwater line break) accident was simulated for the APR+. From the integral effect test result, it could be concluded that the APR+ has the capability of coping with the hypothetical FLB accident by adopting PAFS and proper set-points of its operation.

• 한국추진공학회지
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• 제11권3호
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• pp.20-28
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• 2007

압축기의 써지 현상을 관찰하는 가장 쉬운 방법의 하나로는 부분품의 성능특성도상에 정적 그리고 동적 운용 특성을 나타내는 것이 될 수 있다. 이 경우 엔진의 작동범위가 써지 범위에 의하여 제한될 것이고 따라서 엔진은 엔진의 정적 또는 과도 성능의 전 과정에 걸쳐 일정한 써지 한계를 갖도록 요구되고 있다. 로터의 극관성 모멘트, 닥트 내 공기/가스의 용적 그리고 열전달 효과 등은 엔진의 작동이 정적 특성으로부터 일탈하게 되는 주요 요소들이다. 시스템 내에서 열교환기가 존재하는 경우처럼 큰 용적의 경우 그것은 동적 작동 특성에 상당한 영향을 주게 될 것인데 본 논문에서는 보조동력기관으로 사용되는 마이크로터빈의 예를 들어 엔진의 과도성능 특성에 압축기의 출구에서 추출되는 냉각공기가 미치는 영향을 조사코자 하였다. 질량 및 일 그리고 회전수 일치 법칙에 근거하여 터빈을 흐르는 가스 유량, 압력비, 회전 속도, 동력 그리고 모멘트가 계산되었다. 본 연구의 결과는 제어시스템 설계를 위한 기초 자료로 활용될 수 있을 것이다. 이러한 과도 성능을 계산하기 위한 프로그램을 개발을 위해서 상업용 MathCAD 소프트웨어를 사용하였다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.153-157
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• 2009

A Highly efficient Mercury-free Flat Fluorescent Lamp (MFFL) with dielectric barrier Xe gas discharge was developed for an alternative of conventional line-type Cold Cathode Fluorescent Lamps (CCFLs) which shows a wide voltage margin and a stable discharge operation for diffuse glow discharge with an application of a auxiliary electrode. Electro-optic characteristics of the MFFL were examined through the changes in ambient temperature, total pressure and Xe partial pressure. the single cell is expanded into a multi-structured configuration to realize a large sized lamp by a simple repetition of the single cells, and a new driving scheme is proposed for an adaptive brightness control using dual auxiliary electrodes and bi-polar drive scheme. In addition, interesting application of this ultra high luminance flat lamp by the optimization of the gas condition and the pattern of the rear phosphor layer is suggested as a good alternative of daylight lamp source

• 한국전자파학회논문지
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• 제10권1호
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• pp.1-10
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• 1999

본 논문에서는 100 Mb/s Unshielded Twisted Pairs (UTP) 케이블 Modular Jack의 평형 통신 시스템(Balanced Communication System)에서 시스템의 성능에 영향을 주지 않으변서, UTP 케이블의 꼬임이 풀림 으로 인해 서로 근접하게 배치된 평형통신 선로(Balanced Communication Lines)간에 존재하는 불균일한 결 합으로 인한 차등 누화 선호(Differen tial- Mode Crosstalk Signal)를 효과적으로 제거하거나 억제시킬 수 있는 접근 방법에 대하여 논하고 있으며, 실제 UTP 케이블의 Modular Jack에 이를 적용시켜 이에 대한 큰단누화 (Near-End Crosstalk (Next)를 측정함으로써 그 타당성을 입증하였다.

• 전기학회논문지
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• 제65권5호
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• pp.878-882
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• 2016

These days, SFCLs are being developed in order to limit fault current. However, the superconducting elements that limit the fault current have such problems as capacity increase and require auxiliary devices including cooling device. If devices that comprise the current power network can withstand fault current for at least one cycle, it is possible to limit the fault current with current limiting elements by bypassing it on the fault line. In this study, the fault current limiter was configured with current transformer, vacuum interrupter, and current limiting element. Through the experience, it was confirmed that the fault current was limited within one cycle. The superconducting element, as a current limiting element, limited the fault current by 80 % within one cycle from fault occurrence, and the passive element limited it more than 95 %. Also, through the comparison between resistance curve and power consumption curve, it was confirmed that the current limiting element using a passive element was more stable than the superconducting element that required capacity increase and other auxiliary devices. It was considered that the FCL proposed in this study could limit fault current stably within one cycle from fault occurrence by using the existing power technologies such as fault current detection and solenoid valve operating circuit.

• Journal of Power Electronics
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• 제14권5호
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• pp.815-826
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• 2014

An improved bridgeless interleaved boost power factor correction (PFC) rectifier to improve power efficiency and component utilization is proposed in this study. With combined conventional bridgeless PFC circuit and interleaved technology, the proposed rectifier consists of two interleaved and magnetic inter-coupling boost bridgeless converter cells. Each cell operates alternatively in the critical conduction mode, which can achieve the soft-switching characteristics of the switches and increase power capacity. Auxiliary blocking diodes are employed to eliminate undesired circulating loops and reduce current-sensing noise, which are among the serious drawbacks of a dual-boost PFC rectifier. Magnetic component utilization is improved by symmetrically coupling two inductors on a unique core, which can achieve independence from each other based on the auxiliary diodes. Through the interleaved approach, each switch can operate in the whole line cycle. A simple control scheme is employed in the circuit by using a conventional interleaved controller. The operation principle and theoretical analysis of the converter are presented. A 600 W experimental prototype is built to verify the theoretical analysis and feasibility of the proposed rectifier. System efficiency reaches 97.3% with low total harmonic distortion at full load.