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- 저자 : 崔圭夏 (검색결과 533 건)
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선형전압제어와 고조파제거를 위한 교류전압조정기의 새로운 스위칭 패턴
崔圭夏 건국대학교 1987 學術誌 Vol.31 No.2
A new switching pattern for AC voltage regulator is proposed which can perform both linear control of the fundamental voltage and complete elimination of the harmonic contents up to the specified order corresponding to the modulation number. Through digital computer simulation the overall characteristics such as the changes of switching points to a control variable, the harmonic components of voltage and current and the current ratio are investigated and the modified triangular carrier is derived for practical implementation.
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崔圭夏,李明鍾 건국대학교 1985 學術誌 Vol.29 No.2
Thyristor converters have been widely used in the various industrial fields instead of the mechanical converters since the advent of power semiconductor devices. But the switching operation of these converters makes the current waveform changed abruptly in their input side. Also the nonlinearity of them to ac voltage source gives rise to harmonics and it can be regarded as the harmonic current generator by which many serious problems may be caused in ac power system. In this paper, the PWM current injection method is suggested and analyzed which can suppress the harmonic contents in ac lines. As a result, the PWM current injection can make the contents of the current harmonics, particularly the lower-order harmonics, reduced to the small amounts. In case of adjusting the magnitude of injection current, its optimum value Id* can be determined to minimize the distortion factor of current. AC chopper circuit with R-L load is considered as a nonlinear load model to investigate the harmonic-eliminating characteristics for the injection method. And all the computation results are obtained through the digital computer simulation.
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崔圭夏 建國大學校 産業技術硏究所 1988 논문집 Vol.13 No.-
Current-fed active filters are used to eliminate the harmonics present at the input side of the nonlinear loads such as the rectifiers, inverters. The active filter has so much better characteristics than the conventional passive filter in the aspects of the harmonic elimination, stability, filter cost and structure. In this paper the theoretical studies on the current-fed filter are investigated and the design and the microprocessor control of the filter are performed experimentally on the basis of the computed results.
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崔圭夏 충주대학교 1983 한국교통대학교 논문집 Vol.16 No.1
Modern science and industrial society have been brought up with highly developed technical civilization. And the explosive knowledge is flooded in this society. Therefore it is necessary that the technical junior college curriculum should be re-examined and improved to cope with this trend as a backbone technician needed to modern industrial soeiety. A technical junior college has a problem of its short duration for schooling. In this paper the writer studied on the educational improvement for a technical junior college to train a professional skilled man who can directly work at the industrial spot after his graduation. The contents of this paper are as follows : 1. To research problems and the way of improvement in the matters of curriculum, faculty members, students, the examination of the second-rate engineer, college-industrial cooperation, administration system, and social acceptance of technical junior college. 2. To develop an education by course and a technician education. 3. To present a teaching method and a syllabus.
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崔圭夏 忠州大學校 1980 한국교통대학교 논문집 Vol.13 No.2
A cross figure of projecting part made of Aℓ plate bing operated Bending load, I made a study on concntration Factor of stress and yielding condition operating to fillet weld to be a useful material about the design of the part operate a heavy load.
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