• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.204-210
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• 1997

The paper deals with the design and evaluation of a new static-exciter for generator excitation systems to improve the steady-state and transient stabilities. It increases or maintains the generator field current by boosting the field voltage in the case of an input AC line voltage drop during and immediately after a fault. The validity of the proposed excitation system is verified with computer simulation. The simulation results of the stability analysis on the generator with the proposed exciter is better than that of a conventional static exciter and a conventional AC exciter. Also, this proposed exciter can be simply implemented and controlled by modern power electronics technology.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.426-430
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• 1996

A new generator excitation system using a boost-buck chopper as a kind of static exciters is proposed to overcome the lack of field forcing capability of the bus fed exciter under the Input line fault condition. It increases or maintains the generator field current by boosting the field voltage in the case of the input AC line voltage drop during and immediately after a fault. The validity of the proposed excitation system is verified with the computer simulation. The generator stability according to the each difference exciter is tested using a commercial software package-CYME. The simulation results of the stability analysis on the generator with the proposed exciter is better than that of the bus fed exciter. This boost-buck chopper exciter can be simply implemented and controlled by the modem power electronics technology.

• 전력전자학회논문지
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• 제1권1호
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• pp.47-55
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• 1996

A new generator excitation system using a boost-buck chopper as a kind of static exciters is proposed to overcome the lack of field forcing capability of the bus fed exciter under the input line fault condition. It increases or maintains the generator field current by boosting the field voltage in the case of the input AC line voltage drop during and immediately after a fault. The validity of the proposed excitation system is verified with the computer simulation. The generator stability according to the each difference exciter is tested using a commercial software package-CYME. The simulation results of the stability analysis on the generator with the proposed exciter is better than that of the bus fed exciter. This boost-buck chopper exciter can be simply implemented and controlled by the modern power electronics technology.

• 전기학회논문지
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• 제64권1호
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• pp.8-15
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• 2015

This paper includes a method for estimating the parameter of a synchronous generator and exciter using the modified particle swarm optimization. A solid round rotor synchronous generator and exciter have been modeled with the saturation function. They are regarded as state of being cooperative to a infinite bus. The behavior characteristic of all particles assigned to a parameter needs to be reflected in the PSO algorithm to fine out more close result to the optimal solution. The results of the simulation to estimate the parameters of the synchronous generator and exciter in the modified PSO algorithm are described.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.46-50
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• 2002

In other to evaluate the static and dynamic stiffness of machine tool structure, the accuracy and error from experimental methods are studied in this paper. The F.E.M., impulse tests and exciter tests are performed for the general simple structure whose exact solution can be obtained. So that the parameter and dynamic compliance can be got. From the result, the variation of natural frequency can be verified from the static preload. Further more the relationship of identify and difference for compliance and direction is presented in the exciting direction and measurement direction.

• 에너지공학
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• 제20권2호
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• pp.154-162
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• 2011

예방정비기준은 기기의 높은 신뢰성을 유지하기 위해 정비방법을 문서화한 것으로 기기별 최적화된 예방정비 항목과 주기를 명시하고 기기의 성능저하 메커니즘을 설명하는 지침서이다. 기존의 기기 또는 설비에 대한 정비전략은 상태감시 정비보다는 일정한 주기가 되면 정비를 수행하는 주기정비가 주된 전략이었다. 본 논문은 원전 정지형 여자기에 대하여 기존의 주기정비 형태가 아닌 상태기반 정비 기법을 강화하고 정비 프로그램을 표준화하여 최적화된 정비전략을 구축하기 위한 예방정비 기준을 개발한 내용으로 기기 신뢰성, 발전소 이용률을 향상시킬 수 있는 기반이 될 것으로 판단된다.

• 한국소음진동공학회논문집
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• 제23권3호
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• pp.218-225
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• 2013

Vertically-launched missiles are supported as erected vertically in the vertical launching system of warship, and they should be mounted in the same way when vibration-tested. However, mounting missiles vertically makes a fixture, which is a supporting structure, bulky and heavy so requiring a high-performance exciter. Mounting missiles as laid down horizontally in a vibration test is economical regarding fixture manufacturing and exciter performance, but it makes test results incorrect because the different mounting direction has effects on the test results. A bending moment due to missiles' weight happens to missiles, and resilient mounts, which support missiles in the vertical launch system, deflect differently from the real situation because of the static deflection of these mounts due to missiles' weight. If the resilient mounts supporting missiles have nonlinear force-deflection characteristics, vibration test results become more different from the true results. This paper proposes to support missiles with an additional resilient mount such as a bunge code in order to solve those problems coming from mounting vertically-launched missiles as laid down horizontally in vibration tests. The proposed approach enables to obtain the same test results as in their actual mounting condition even though vertically-launched missiles are mounted in a different direction.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.102-106
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• 2003

An experimental modal analysis and dynamic stiffness evaluation of a moving body structure of a high speed machining center are presented in this paper. The natural frequencies and corresponding modes, and dynamic compliance of a moving body structure of high speed machining center are investigated by using F.E.M., hydraulic exciter test, and impulse hammer test. The lowest three natural frequencies were found to be 56.6 Hz, 112.7 Hz, and 142.7 Hz by FEA respectively, while those were 55 Hz, 112 Hz, 131 Hz by experimental analysis. Furthermore, both computed and measured absolute dynamic compliances of the moving body structure in iso-direction showed good agreement especially at the first two mode frequencies. With our experimental data, the dynamic characteristics of the machining center can be exploited to get a new development of structural dynamic design and modification.

• 에너지공학
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• 제5권1호
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• pp.72-79
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• 1996

본 논문은 전력계통의 안정도에 미치는 제어장치들의 영향과 안정도 개선에 대해 연구하였다. 제어장치로는 여자기와 전력계통안정기(PSS) 그리고 무효전력보상기(SVC)를 일기무한모선계통에 설치하고, 이때의 상태행렬의 구조를 제시하였다. 상태행렬의 구조식과 고유치, 고유벡터로부터 제동이 불량한 고유치에 대한 감도계수를 구하여 각 제어기별로 중요진동모드에 대한 영향을 수치적으로 나타내었다. 또한 계통의 운용조건을 달리하여 계통변화에 따라 제어장치들이 안정도에 미치는 영향을 관찰하였다. 계통의 안정도를 개선시키기 위해서 제어기정수의 일차고유치감도계수를 선형계획법인 심플렉스법에 적용하여 제어기정수의 최적화를 수행하였다 이때 일차고유치감도계수만으로 최적화를 하는데 따른 문제점을 해결하기 위해 각 제어기정수의 변화폭을 좁게 설정하고, 각 반복계산마다 전단계에서 구한 최적 정수값을 제어기정수의 변화범위를 달리하여 다시 최적화하는 방법을 사용하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.169-171
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• 2007

국내 원자력발전소의 주발전기에 사용되는 정지형 여자기를 종류별로 구분하여 분석하였으며 특히 여자기의 주종을 차지하는 정지형 여자기 싸이리스터 컨버터의 전류제어 기를 분석하고 시뮬레이션을 수행하여 계단응답 특성을 고찰하였다.