• 제목/요약/키워드: five weakening

검색결과 21건 처리시간 0.022초

Five-Phase IPM Motor의 약계자 제어 (Field Weakening Control for Five-Phase IPM Motor)

  • 김남훈;김민회;백원식;황돈하;김동희
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2006년도 전력전자학술대회 논문집
    • /
    • pp.95-97
    • /
    • 2006
  • This paper investigates the field weakening operation of a five-phase IPMSM(inner permanent magnet synchronous motor). The five-phase motor can supply sinusoidal voltage and third harmonic voltage because of more freedom of control. This paper present field weakening algorithm and experimental results for five-phase IPMSM which has trapzoidal back-EMF and concentrate winding to prove the validity of the proposed algorithm.

  • PDF

고밀도 토크를 가지는 5상 영구자석형 전동기의 약계자 제어 (Field Weakening Operation of a High Torque Density Five Phase Permanent Magnet Motor Drive)

  • 김남훈
    • 전력전자학회논문지
    • /
    • 제12권4호
    • /
    • pp.318-323
    • /
    • 2007
  • 본 논문에서는 영구자석형 5상 전동기(Five-phase permanent magnet motor)의 약계자 제어에 대한 연구를 수행한다. 제안된 전동기는 집중권 방식의 권선분포를 가지고 있고 사다리꼴 형태의 역기전력을 나타내고 있으며, 사다리꼴 형태의 전류를 인가하기 위하여 사인파의 기본파 성분에 3고조파 성분을 첨가하였다. 따라서 BLDC 전동기(Brushless dc motor)와 등가적으로 같은 평균토크를 발생시키면서 BLDC 전동기의 단점을 극복할 수 있었다. 전동기 전류의 토크성분과 자속성분은 다중 레퍼런스 프래임을 이용하여 분리할 수 있었으며, 결과적으로 쉽게 벡터제어가 이루어질 수 있었다. 사용된 전동기는 고속영역에서부터 저속영역까지 BLDC 전동기와 같이 높은 토크 밀도를 가지며, 약계자 영역이나 고속영역에서 영구자석형 전동기와 같이 제어의 용이함을 가진다는 장점을 가지고 있으며 실험결과를 통하여 제안된 전동기와 알고리즘을 검증하였다.

한약 장기복용이 발달장애아동의 간기능과 건강증진에 미치는 영향 (Influence of Taking Medicine for a Period of Time on the Liver Function and Improvement of the Developmental Disordered Children)

  • 박재형;박재현;윤영주;정슬기;이현정;임자성;반건호;문진수;백은경
    • 동의생리병리학회지
    • /
    • 제20권2호
    • /
    • pp.494-497
    • /
    • 2006
  • A child with five delay, five ankylosis, five weakening needs to take herbal medicine for a long term. So safety, efficacy inspection for the long term usage of herbal medicine and mixed dose is needed because other medication or functional health foods, etc could be taken during this process. Operated liver function test before and after dosing herbal medicine to one hundred and sixty children who aided private oriental medicine located in Seoul, and measured the efficacy by comparing sleeping hours, morbidity, stamina, sanguineness, personality, digestion with the state before taking herbal medicine based on questionnaire done by the parents. Every children were under the limits, and there were no differences between boys and girls, and no notable differences according to family histories. There were positive results in efficacy inspection ordered as improvement in personality, stamina, sanguineness, decrease in morbidity, increase in appetite, digestion. No signs of disorder in liver function has been found during the dose of herbal medicine or simultaneous medicine, and shown promotion of health.

Comparative Analysis of Magnetic Slot Wedges Design for Increasing Performance of Railway Traction Motor

  • Liu, Huai-Cong;Cho, Sooyoung;Hong, Hyun-Seok;Joo, Kyoung-Jin;Ham, Sang-Hwan;Lee, Ju
    • Journal of Electrical Engineering and Technology
    • /
    • 제12권6호
    • /
    • pp.2411-2418
    • /
    • 2017
  • This study focuses on the effects of using open stator slots in an interior permanent magnet traction motor with a magnetic slot wedge design in order to increase the power density at its base speed. In addition, such a configuration reduces the torque ripple under field-weakening conditions. Five different wedge models were selected, each of which was evaluated using a finite element analysis (FEA). Based on the initial model, we designed magnetic slot wedges for maximum back-EMF and minimum cogging torque. In addition, the d-q axis inductance was slightly altered due to the magnetic slot wedges. Finally, we analyzed the performance of a traction machine under field weakening control. Moreover, we have outlined the requirements for an ideal magnetic slot wedge design.

Association between business switch or liquidation, and the demographics of Small and Medium Enterprises in South Korea

  • Jeong, Dong-Bin
    • 산경연구논집
    • /
    • 제9권9호
    • /
    • pp.25-33
    • /
    • 2018
  • Purpose - In this study, we consider and examine relationships between reasons for business switch or liquidation (BSL), and the demographics of small and medium enterprises (SMEs) in South Korea. The related five variables are occupations, administrative districts, age of employer, firm age and foundation motivation. In addition, eleven levels in association with reasons for BSL visualize the corresponding demographics by measuring their similarity on the dimensional planes assuming that the association exists between variables under consideration. Research design, data, and methodology - This study is done by the Ministry of SMEs and Startups in 2016 and examines 20,307 small and medium enterprises. For examining the distinct relationships among variables under consideration, both chi-squared test and correspondence analysis as main statistical tools are used. Results - The results show that among levels of reasons for BSL the three levels -weakening profitability, poor sales and economic depression- are main ones for the five demographics variables mentioned above, and we can obtain the detailed associations between attributes of corresponding variables by inspecting the two dimensional plane. Conclusions - This study suggests reasons for BSL are closely associated with the five different demographics variables - Administrative districts, Firm age, Occupations, Age of employer and Foundation motivation-by looking over results.

제품태도에 대한 회복노력의 차별적 효과 (Differential Effects of Recovery Efforts on Products Attitudes)

  • 김천길;최정미
    • 마케팅과학연구
    • /
    • 제18권1호
    • /
    • pp.33-58
    • /
    • 2008
  • 본 연구는 서비스실패가 아니라 제품실패 이후, 회복노력의 효과를 실패심각성에 따라 확인하는 것이다. 회복노력은 보상노력, 장점노력 및 단점노력으로 구분되었다. 보상노력은 실패상황을 직접적으로 되돌리려는 의도로 구체적인 보상을 제공하는 방안으로, 장점노력은 제품실패를 초래하는 이유가 특정한 장점을 추구하는 과정에서 불가피하게 발생할 수 있는 문제임을 언급하는 것과 같이 추가적인 상대적 장점을 설명하는 방식으로, 그리고 단점노력은 자사제품이 서비스실패를 초래할 수 있는 문제점을 지니고 있는 반면에 경쟁제품은 또 다른 측면의 단점을 지니고 있다는 점을 부각시켜 소비자의 자사제품에 대한 부정적 태도를 회복시키려고 방안이라고 개념화되었다. 그러한 회복노력들이 실질적으로 효과가 있다고 결론을 내리기 위해서, 회복노력이 제공되지 않는 상황과 비교하여 소비자의 태도나 의향이 우호적인지 검토된다. 가설검증을 위해 화장품산업에서 소비자들을 대상으로 가상적인 시나리오를 이용한 실험을 실시하였다. 연구 결과, 전반적으로 회복노력들은 효과적인 전략임이 확인되었고, 보상노력은 장점노력이나 단점 노력보다 효과적이었다. 특히 심각성이 높은 실패조건에서 단점노력은 장점노력보다 긍정적인 제품태도를 유도하였다. 심각성이 낮은 실패조건에서 장점노력과 장점노력의 효과는 기대할 수 없었다.

  • PDF

Factors governing dynamic response of steel-foam ceramic protected RC slabs under blast loads

  • Hou, Xiaomeng;Liu, Kunyu;Cao, Shaojun;Rong, Qin
    • Steel and Composite Structures
    • /
    • 제33권3호
    • /
    • pp.333-346
    • /
    • 2019
  • Foam ceramic materials contribute to the explosion effect weakening on concrete structures, due to the corresponding excellent energy absorption ability. The blast resistance of concrete members could be improved through steel-foam ceramics as protective cladding layers. An approach for the modeling of dynamic response of steel-foam ceramic protected reinforced concrete (Steel-FC-RC) slabs under blast loading was presented with the LS-DYNA software. The orthogonal analysis (five factors with five levels) under three degrees of blast loads was conducted. The influence rankings and trend laws were further analyzed. The dynamic displacement of the slab bottom was significantly reduced by increasing the thickness of steel plate, foam ceramic and RC slab, while the displacement decreased slightly as the steel yield strength and the compressive strength of concrete increased. However, the optimized efficiency of blast resistance decreases with factors increase to higher level. Moreover, an efficient design method was reported based on the orthogonal analysis.

수산업협동조합중앙회장의 명예직화에서 본 지배구조의 문제점 (Problem on the Governing Body of National Federation of Fisheries Cooperatives (NFFC) - from the perspective of the Honorary Office of NFFC President -)

  • 전형수
    • 수산경영론집
    • /
    • 제40권1호
    • /
    • pp.97-112
    • /
    • 2009
  • The amendment of regulation affecting the Governing Body of NFFC (National Federation of Fisheries Cooperatives) has been known to the public in May 2008. Its essential points are as follow: 1) the President of NFFC shall be a non-standing officer. 2) the Full-Time Directors shall have the authority to deal with all subjects except for those especially reserved for the General Meeting or Board of Directors, while minimizing the authority of NFFC President. By providing this amendment, the government seeks to make the Governing body becomes professionalized and the management functions carried out by full-time professional board members. However, the amendment seems to pay no attention to the co-operative's identity and principles. In this context, five issues will be discussed: 1) Strengthening the separation between ownership and control of NFFC. 2) Weakening the authority of General Meeting. 3) The bounds of Audit Committee. 4) Consolidating the management control of the Full-Time Directors. 5) The loss of NFFC's Identity, followed by a summary and conclusion.

  • PDF

3차 고조파의 영향을 고려한 5상 유도전동기의 약계자 운전 (Field Weakening Control for Five-Phase Induction Motor Drives considering the Effect of the 3rd Harmonic)

  • 강성윤;신혜웅;이교범
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2015년도 전력전자학술대회 논문집
    • /
    • pp.343-344
    • /
    • 2015
  • 본 논문은 고속영역에서 3차 고조파의 영향을 고려한 5상 유도전동기의 약계자 운전을 제안한다. 5상 유도전동기는 집중권의 형태로 되어있어 공극 자속이 제 3차 공간 고조파 성분을 포함한다. 따라서 5상 유도전동기의 역기전력은 3차 고조파가 포함된 형태이므로, 5상 유도전동기의 약계자 운전은 3차 고조파 성분을 고려하여 수행해야 한다. 약계자 운전에 앞서 정격 이하의 속도에서는 간접벡터제어를 사용하고, 정격이상의 고속 영역에서는 최대 토크 발생과 전압 및 전류 제한 영역을 고려한 약계자 운전을 수행한다. 본 논문에서는 3차 고조파를 고려한 5상 유도전동기의 약계자 운전을 시뮬레이션으로 검증한다.

  • PDF

명대(明代)의 소아과학(小兒科學)에 관(關)한 연구(硏究) (The Medical Study on the Development of Pediatrics in Myeong(明) Dynasty)

  • 박현국;김기욱;이영석
    • 대한한의학원전학회지
    • /
    • 제21권3호
    • /
    • pp.1-25
    • /
    • 2008
  • Myeong(明) Dynasty Period put together clinically various medical theory in Song(宋) Dynasty and Geum-Won(金元) age, organized medical system. They have been developed in theory, which thought of Byeonjeungronchi(辨證論治) more important, and clinical part which included diagnosis, therapy, prevention. In that age reactional medical thought was in fashion because of affect of Ihak(理學), therefore pediatrics have been affected from them. Especially, looking at the symptom of Byeonjeungronchi doctors, Manjeon(萬全), Nobaeksa(魯伯嗣), Wangdaeryun(王大綸), Wanggeungdang(王肯堂), Nuyeong(樓英) had succeed to Jeoneul(錢乙)' the five viscera Byeonjeung(辨證) system. Manjeon advocated Samyuyeosabujokron(三有餘四不足論) about Jangbu(臟腑) and organized the curative principle about Ojangheosil(五臟虛實). Gupyeong(寇平), commented on diagnosis of five viscera and classification of disease of five viscera. Wangdaeryun in the close of Myeong Dynasty Age explained main pulse, pulse of illness in detail according to weakness or strength of five viscera, pathological or physiological features of five viscera and Saenggeuk(生克) relation of Ohaeng(五行) in the book of "Yeongdongryuchwe(嬰童類萃)". Wanggeungdang and Nuyeong had organized system of argument which classified disease as a result of symptom of five viscera. "Yugwajeungchijunseung(幼科證治準繩)" and "Uihakgangmok(醫學綱目) Soabu(小兒部)" had been written by this principle. Nobaeksa had arranged the principle of cure about five viscera and explained method of common use about each organ's disease. Besides, Seolgi(薛己), Janggyeong-ak(張景岳), insisted about Myeongmun(命門) because he thought of Bisin(脾腎) of children and vigor by nature importance. Seolgi had applied and used very well Bojung-ikgitang(補中益氣湯) based on Idongwon(李東垣)'s Biwiseol(脾胃說) and controled and helped spleen and stomach. At the same time, he took a serious view about supplementing children's Sin-gi(腎氣) according to so many spleen and stomach disease was fallen because they couldn't make warm the spirit of Jungju(中州), result of weakening Hwa(火) of Myeongmun. Also Janggyeong-ak took a serious view strengthen of Bisin, so he assorted and used Insam(人蔘) and Buja(附子) to supplement children's weaken energy in kidney Jeonggi(精氣).

  • PDF