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- 저자 : 이우철 ( Lee U Cheol ) (검색결과 215 건)
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A Study on DC Changing Algorithm of the Line-Interactive UPS with Dual Converter Structure
이우철,유동상,Lee, Woo-Cheol,Yoo, Dong-Sang The Korean Institute of IIIuminating and Electrica 2005 조명·전기설비학회논문지 Vol.19 No.3
본 논문에서는 2개의 컨버터 구조를 갖는 삼상 계통 연계형 UPS에 대하여 연구한다. 삼상UPS시스템은 2개의 능동 전력 보상기 구조로 이루어져 있다. 하나는 직렬형으로 .전원전압과 동상의 전압원으로 동작하여 전원전압의 변동, 왜곡시에도 정현파 전원전류와 고역률을 갖도록 동작한다. 병렬형은 전원전압과 위상을 맞춘 종전의 정현파 전압원으로 동작하여 부하에 안정되고 낮은 THD를 갖는 정현파 전압을 공급한다. 본 논문에서는 직렬형, 병렬형 능동보상기에서 전원전압의 크기에 따라 충전 방법에 대하여 제시한다. 종전의 계통 연계형 UPS는 DC 충전과 출력전압을 동시에 제어하였는데, 2개의 컨버터 구조를 갖는 UPS 시스템에서는 직렬형 보상기도 DC 충전을 할 수 있어 직렬형과 병렬형을 사용한 충전 알고리듬을 연구할 필요가 있다. 따라서 DC link단의 전압을 안정시켜 본래의 직렬형, 병렬형 구조의 보상기의 안정성 향상에 기여할 수가 있다. 제안된 방법의 타당성은 시뮬레이션과 실험 결과를 통하여 입증된다. This paper presents a three phase Line-Interactive uninterruptible power supply(UPS) system with dual converter structure. The three phase UPS system consists of two active power compensator topologies. One is a series active compensator, which works as a voltage source in phase with the source voltage to have the sinusoidal source current and high power factor under the deviation and distortion of the source voltage. The other is a parallel active compensator, which works as a conventional sinusoidal voltage source in phase with the source voltage, providing to the load a regulated and sinusoidal voltage with low total harmonic distortion(THD). This paper presents in the series and parallel active compensator charging method depending on the amplitude of the source voltage. The conventional Line-Interactive UPS system is responsible for the DC charging and output voltage regulation at the same time, but UPS system with dual converter structure, a series active compensator can also charge the DC link. Therefore the charging algorithm using the series and parallel compensator needs to be researched. Therefore, by making the DC link voltage stable it can contribute the stability of series and parallel compensator. The simulation and experimental result are depicted in this paper to show the effect of the proposed algorithm.
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이우철,사공석진,Lee, Woo-Cheol,SaKong, Sug-Chin 대한전자공학회 2005 電子工學會論文誌 IE (Industry electronics) Vol.42 No.3
The 24 channel meridian electric-potential measuring System consists of a main cpu module, bio-signal analog module, interface module, power module, personal computer. The graphic user interface program conveniently allows user to setup, calibrate, measure, store, and control the meridian electric-potential measuring system. This system and program will continually be evolved using a database of clinically correlated meridian electric-potential. A variety of system configurations gives it the ability to make a user-favorable environment for measuring. 개발된 24 채널 경락 전위측정 시스템의 구성은 마이컴 제어부, 생체신호 아날로그 증폭부, 인터페이스부, 전원장치, personal computer 등 이다. 사용자 인터페이스 프로그램은 이용자를 편리하게 구성하였으며, 측정의 편리성으로 calibration기능 및 자료의 저장 과 검색 기능을 하게 하였다. 경락 전위를 측정하기 위한 프로그램을 구성하여 제어 할 수 있게 하였다. 측정된 생체 전기 신호 자료의 분석을 통하여 각각의 위치에 대한 전위의 상호 분포를 비교하여 결과를 체계적으로 나타낼 수 있게 프로그램 처리 하였다. 다양한 종류의 측정 조건을 변화 할 수 있게 구성하여 경락 전위를 측정을 위한 이용자에게 유리한 측정 환경이 되게 하였다.
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李雨哲(Woo-Cheol Lee),印昌植(Chang-Shik Yin),閔庚基(Kyoung-Kee Min) 대한전기학회 2009 전기학회논문지 Vol.58 No.2
Meridian which used as the basic theory of acupuncture treatment, is an important functional connection system of acupuncture point in oriental medicine. Yangdorak and EAV have lack of precision because of using 2-electrode method, occurring high non-uniformed current density and electrode contact status on electrode placement spot. Therefore we implemented a meridian impedance measurement system for measuring meridian impedance using 4-electrode method. In order to confirm the precision of developed system, we made an constant current characteristic experiment using standard resistor. As a results of clinical study with 18 subjects, the meridian impedance showed that reproductivity and repeatability of HTI acupuncture point are 0.515[㏀]±0.000(mean±standard deviation} and 0.515[㏀]±0.002, respectively. And reproductivity and repeatability of PC7 are 0.521[㏀]±0.000 and 0.52l[Ω]±0.001, respectively. The proposed system was stable and reliable. Therefore this study proved AC impedance method to valid in measuring meridian impedance, and also verified precision and repeatability of the proposed meridian impedance measurement system. The proposed system will serve as more effective method of measuring meridian phenomena as a bioelectric signal in clinical practice.
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이우철(Lee Woo Cheol) 언어과학회 2004 언어과학연구 Vol.28 No.-
In this thesis, the preceding study results regarding the S-P predicate sentence^(1)), the reason why the results can hardly be adapted to a practical education of Chinese, and individual features of the S-P predicate sentence were reviewed. The following results were discovered. (a) The S-P predicate sentence is a basic sentence type whose frequency of usage is commonly high in ancient Chinese and modern Chinese. (b) In the syntactic analysis of the S-P predicate sentence, the explanation can be made only using a subject instead of using both a subject and a topic whose concepts are different from each other. By doing so, the burden of education for the students can be decreased. (c) Using a subject of the S-P predicate sentence, subjective intention of a speaker such as `emphasis` and `prominence` can be realized in a sentence in many cases. (d) Pause sentence-final particles such as ‘??, ??, ??, ??, ??’ can be appeared frequently between a subject and a predicate of an S-P predicate sentence. This may mean that the meaning of a subject and a predicate can be alienated a lot at times. (e) In the pedagogy of Chinese conversation, the S-P predicate sentence should be treated as a basic sentence type, because the S-P predicate sentence uses well the feature of Chinese devoid of the grammatical form, and it is a sentence type that can elevate the force of expression. (f) The feature of structural parallelism that exists after the head part of a sentence shows a powerful rhetorical contrast functions.
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이우철(Woo Cheol Lee) 언어과학회 2004 언어과학연구 Vol.30 No.-
Chinese is a language which has Chinese characters. Chinese characters are prominently characterized by a semantic representation, and a lot of data for them have been accumulated because they have been used for thousands of years. Historically, the Korean language is closely associated with Chinese characters. Because of the necessity of the acquisition of the Chinese and of the comprehension of Chinese characters, we have to reflect these features when we research and educate the Chinese language. A character unit reflects such features. Principal contents of the `character unit` are summarized as follows: First, a Chinese character, the basic unit of Chinese, has `visuality` and `psychological reality` which anyone using Chinese can recognize easily with eyes. Second, Chinese is a language based on semantics and has the sentence structure composed of a topic and a comment. These contents can be the theoretical basis of the Chinese education mentioned in Chapter 4. Although the theory of the character unit has some problems to be solved theoretically, the proper application of it to the education course can give a good studying method to learners like us who are familiar with Chinese characters. Moreover, the theory of the character unit enables us to explain clearly the part of Chinese that has been hard to explain up to now.
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