• 제목/요약/키워드: Circulating Power

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No-Yong Park's Passing as Political Gestures

  • Park, Heui-Yung
    • 영어영문학
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    • 제64권2호
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    • pp.219-238
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    • 2018
  • This essay examines the first-generation Korean American writer, No-Yong Park's falsehoods about his ethnic identity to suggest how and why he passed for Chinese, and to explore the political, anti-Japanese implications of these actions. The essay first identifies erroneous information circulating about his biographical background, presents some other materials that help us better understand the context in which he forged his Chinese identity, and then examines how he represented himself as Chinese in his published works. I would argue that Park's self-identification as Chinese was a resulting outcome of his naturalization caused by the Japanese colonial power in Korea and also one of his surviving strategies in the racist environment within American society. Looking at some of his works-including Making a New China (1929), An Oriental View of American Civilization (1934), Chinaman's Chance: Autobiography (1940)-and examining how he represented Korea and its people reveal how he tried to raise voice for them. By doing so, this essay illuminates Park's resistance to Japan's colonial discourse and power in Korea while revealing his lifetime passing as Chinese-far from his refusal to belong to the Korean community, or to acknowledge being Korean.

병렬 구성 인버터 운전 시 순환전류 제어 방법 (A Novel Circulating Current Control Method for Parallel Interleaved Three-Phase Voltage Source Inverters)

  • 김기룡;신동설;이종필;김태진;유동욱;김희제
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2016년도 전력전자학술대회 논문집
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    • pp.481-482
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    • 2016
  • 병렬 운전 시 인터리빙 기술은 인버터 최종 출력 전류에 포함되는 스위칭 주파수 성분의 고조파를 제거하는 장점을 가지고 있지만 이로 인해 고주파 성분의 영상분 순환 전류를 만든다. 따라서 이 성분을 억제하기 위해 커플드 인덕터가 같이 사용된다. 하지만 커플드 인덕터를 사용할 경우에는 파라메타의 오차로 인해 안정성에 문제가 발생 할 수 있다. 따라서 본 논문에서는 인터리빙 및 커플드 인덕터를 사용한 병렬 운전 인버터 시스템에서 전류 품질 개선을 위해 고조파 보상을 할 경우 발생 할 수 있는 안정성 문제에 대한 원인을 규명하고 새로운 순환전류 제어 방법에 대해 제안하고 실험을 통해 검증하였다.

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3상 2-병렬 PWM 컨버터의 고장허용 제어 및 순환전류 저감에 관한 연구 (Study of Fault Tolerant and Circulating Current Control Method for Three-Phase 2-Parallel PWM Converter Systems)

  • 박진우;정준형;김장목
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2016년도 전력전자학술대회 논문집
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    • pp.58-59
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    • 2016
  • 본 논문에서는 3상 2-병렬 PWM 컨버터의 단일 스위치 개방 고장 시 고장 허용 제어 방법과 그에 따라 발생하는 순환전류를 저감하는 연구를 진행 하였다. PWM 컨버터의 스위치 개방 고장은 DC단 전압 맥동과 계통 측 전류의 왜곡을 유발하며 이는 고장허용제어를 통해 개선 가능하다. 하지만 고장허용제어를 병렬형 PWM 컨버터에 적용하는 경우에는 컨버터의 비동기적인 스위칭으로 발생된 순환 전류 때문에 기존의 방법을 적용 할 수 없다. 따라서 본 논문에서는 2-병렬 PWM 컨버터의 스위치 개방 고장 허용제어에 따른 순환전류 저감에 대한 연구를 진행하였다. 연구한 내용은 시뮬레이션을 통해 확인하였다.

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DC 배전용 3상 AC/DC 컨버터의 병렬 운전시 발생하는 순환전류 제어 알고리즘 (Control Algorithm for Circulating Currents in Parallel Operation of Three-Phase AC/DC Converter for DC Distribution System)

  • 정철호;신수철;정태복;이택기;원충연
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2011년도 추계학술대회
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    • pp.167-168
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    • 2011
  • 본 논문에서는 여러 대의 전력변환장치를 모듈화 하여 병렬 운전할시 필연적으로 발생하게 되는 순환전류를 억제하기 위한 제어 기법을 제안하였다. 이에 따라 병렬 운전 시스템이 갖는 응답 특성 및 정상상태 동작 등의 타당성을 시뮬레이션 모델을 통하여 검토하였다.

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초고압 대용량 모델변압기의 유동대전 현상에 관한 연구(전압무인가) (A Study on the Streaming Electrification in the Super-high Voltage Model Transformer)

  • 이덕출;박재윤
    • 대한전기학회논문지
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    • 제40권6호
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    • pp.619-625
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    • 1991
  • Phenomena of streaming electrification of insulting oil(T.O) is studied where the oil is contacted with solid insulating materials when it is pumped through a circulating system in a large power transformer. The leakage current, the electrical potential at the neutral terminal point of the transformer and the surface electrical potential of the oil are investigated. And the leakage current from the neutral terminal point is measured as a function of a bias polarity applied to a transformer case to investigate the polarty of ion which is absorbed in the case at the interface between the case and oil. As a result, it is found that insulating materials, and it is suggested that the leakage current is the sum of the relaxation current by positive charge from insulating oil to the neutral terminal point and by electrification current from negative charge electrified by the contact with solid insulating materials.

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Diagnosis in Beding Fatigue of Spur Gear Teeth

  • Sentoku, Hirofumi;Tokuda, Takashi
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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    • pp.307-311
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    • 1993
  • Research concerning gears included in rotating machines has been reported using the acoustic emission (AE) method, however, almost no research has been conducted using the AE method in regard to running gears in a bending fatigue processor spur gear teeth. Therefore, in this report, a power circulating-type gear testing machine was used and AE signals and crack length were measured in the bending fatigue process of case-hardened spur gear. Furthermore, the envelope of the AE signal was detected and various analysis were carried out in this data. In the course of the experiments, the following results were observed : the AE signal envelope consists mainly of contact frequency component and twice as many as this;two peaks of AE appear in each tooth contact by the tip corner contact ; as a result of the severe tip corner contact ; as a result of the severe tip corner contact with the sudden increase of crack length, AE signal becomes large.

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13kW급 고주파 ZVS FB DC-DC 콘버터 개발 (A Study on the Development of A 13kW High Frequency ZVS FB DC-DC Converter)

  • 김은수;조기연;이재훈
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1994년도 하계학술대회 논문집 A
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    • pp.542-546
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    • 1994
  • The objective of the study is to design and develope a 13kW zero voltage switching DC-DC Converter far high power application. Due to using the snubber capacitor in the right leg instead of increasing transformer leakage inductance, DC characteristics and the total efficiency in the proposed ZVS DC-DC converter is increased mere than in the conventional ZVS DC-DC converter by reduction of the circulating current when the load current is large. Also, this paper includes simulation and experimental results of the proposed ZVS FB DC-DC converter.

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ZVT 인터리브드 Flyback 컨버터의 손실 저감을 위한 보조 회로 설계 (Design of Auxiliary Circuit to Reduce Loss of ZVT Interleaved Flyback Converter)

  • 정원상;이순령;이종영;박윤지;원충연;이제현
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2017년도 추계학술대회
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    • pp.43-44
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    • 2017
  • This paper presents design of auxiliary circuit to reduce loss of ZVT interleaved flyback converter. The ZVT interleaved converter using the conventional auxiliary circuit has a large conduction loss due to the constant circulating current in the auxiliary circuit. The auxiliary circuit proposed in this paper, which consists of the coupled inductor and DC-link capacitor, has linearly increasing or decreasing auxiliary current. Then, the conduction loss occurring in the auxiliary circuit is reduced. The validity of the proposed auxiliary circuit is verified with the prototype of 500W.

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표면처리에 따른 평기어 치의 표면거칠기 변화에 관한 연구 (A Study on the Surface Roughness Variation of Spur Gear Teeth as a function of the Surface Treatment)

  • 유장열;이성철;권오관;정태형
    • Tribology and Lubricants
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    • 제7권2호
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    • pp.67-74
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    • 1991
  • The contact characteristics of gear tooth surface were studied by using the gear test rig of power circulation type. The effect of surface treatment conditions and revolutions on the tooth surface roughness parameters, and the relations between the lubrication conditions and tooth surface conditions, in spur gear sets wear considered. The result show that heat treatment of gear have an important effect upon fatigue strength and tooth surface conditions, and surface asperities undergo a circulating process of creation and destruction because of the influnce of plastic deformation. And surface roughness conditions at the tooth tips accompany a great deal of variation in running-in stage. According to the lubrication analysis and the study the tooth surface have a greater effect on surface demage than lubrication conditions, in mixed-lubrication condition.

개선된 영전류 과도상태 PWM 스위치 셀 (Improved Zero-Current- Transition (ZCT) PWM Switch Cell)

  • 최항석;조보형
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 하계학술대회 논문집 B
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    • pp.950-952
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    • 2001
  • This paper proposes a new zero-current transition (ZCT) pulse-width modulation (PWM) switch cell that overcomes the limitations of the conventional ZCT converters. The proposed ZCT cell provides zero-current-switching (ZCS) condition for the main switch and the auxiliary switch. The conduction loss and current stress of the main switch are minimized, since the circulating current for the soft switching does not flow through the main switch. The proposed ZCT PWM switch cell is suitable for the high power applications employing IGBTs. Design guidelines with a design example are described and verified by experimental results from the 1 kW prototype boost converter operating at 70kHz.

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