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풍력발전용 영구자석 다극 동기발전기의 코깅토크의 해석 및 저감
張錫明(Seok-Myeong Jang),崔璋英(Jang-Young Choi),李成浩(Sung-Ho Lee) 대한전기학회 2008 전기학회논문지 Vol.57 No.3
This paper deals with reduction and analysis of cogging torque for permanent magnet synchronous generators with multi-pole rotor for wind power applications. Open-circuit field solutions are derived using a magnetic vector potential and a two-dimensional (2-d) polar coordinate systems. On the basis of derived open-circuit field solutions and 2-d permeance functions, we also derive open-circuit field solutions considering stator slotting effects. By using open-circuit field solutions considering stator slotting effects and energy variation methods, this paper analytically predicts the cogging torque considering skew effects. All analytical results are shown in good agreement with those obtained from finite element (FE) analyses. In order to reduce the cogging torque, by predicting the variation of the cogging torque according to pole arc/pitch ratio using analytical and FE methods, pole arc/pitch ratio which makes the cogging torque minimum are determined. However, we confirm that measured value for cogging torque of the PMG with determined pole arc/pitch ratio is twice higher than predicted value. Therefore, the reason for an error between measured and predicted cogging torque is discussed in terms of a shape of PMs and is proved experimentally.
일단중심 타단편심 압축력을 받는 스테인리스 원형강관 기둥의 좌굴내력에 관한 실험적 연구
장호주(Jang Ho-Ju),박재선(Park Jae-Seon),양영성(Yang Young-Sun) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.11
This study presents a series of experimental investigations on buckling strength of one way concentric and the other way eccentric compressive cold-formed stainless steel CHS(circular hollow section) columns. The principal parameters in this study are slenderness ratios(Lk/r=30, 50, 70) and magnitude of eccentricity e(0, 25, 50, 75, 100㎜) for single-curvature asymmetrical end moment. Objectives of this study are to obtain the maximum loads by performing an experimental work and to compare the experimental behaviors with analytical results. The ultimate buckling strength of CHS members are evaluated by a numerical method for axial force-bending moment(P-M) interaction curves. The behavior of each specimen is displayed in the form of strength-displacement and moment-angle(M- θ) relationship. The numerically obtained ultimate buckling interaction curves of columns show a reasonably good agreement with the available experimental results for slenderness ratio 30, 50, 70. But experimental results for slenderness ratios 30(e/k=0) were below M-P interaction curve.
장재삼(Jae-Sam Jang),김철복(Cheol-Bok Kim),이호상(Ho-Sang Lee),정영호(Young-Ho Jung),조동기(Dong-Ki Jo),이문수(Mun-Soo Lee) 대한전자공학회 2008 電子工學會論文誌-TC (Telecommunications) Vol.45 No.5
본 연구에서는 위상배열 안테나의 기본방사소자로 사용될 선형 테이퍼형 슬롯 안테나를 설계ㆍ제작하여 그 특성을 실험적으로 고찰 한다. 테이퍼형 슬롯 안테나(TSA)는 박막, 경량, 간단한 제조와 고주파 단일 집적회로에 적합하다. 또한, 멀티 옥타브 대역폭, 적절한 높은 이득, 대칭적인 E-면과 H-면 방사패턴을 가진다. 마이크로스트립 선형 테이퍼형 안테나의 급전회로는 마이크로스트립-슬롯 선로간의 트랜지션을 사용한다. 트랜지션은 두 면으로 이루어진다. 한쪽 면은 마이크로스트립 선로이고, 다른 한쪽은 슬롯 선로를 가지는 구조이다. 마이크로스트립 과 슬롯 선로의 길이는 마이크로스트립과 슬롯 선로의 교차면의 중앙에서 λm/4과 λs/4이다. 넓은 대역폭을 얻기 위하여, 슬롯 선로의 종단부의 폭은 1.75λ?로 하고, 큰 지향성을 얻기 위하여 슬롯 선로의 테이퍼된 길이는 4λ?로 한다. 실험결과 마이크로스트립 선형 테이퍼형 슬롯 안테나는 5㎓의 중심 주파수에서 약 5㎓의 대역폭을 가지고, 대칭적인 E-면과 H-면 방사패턴을 가진다. In this paper, a microstrip linear tapered slot antenna is designed. A tapered slot antenna(TSA) has many advantages such as low profile, low weight, easy fabrication, and compatibility with monolithic microwave integrated circuits(MMIC). In addition, it has demonstrated multi octave bandwidth, moderately high gain, and symmetrical E- and H-plane beam patterns. A feed network is implemented with transition between a microstrip and a slot line for the microstrip linear tapered slot antenna. The transition is consist of two sides. One side has a microstrip line, the other side has a slot line. The dimensions of the microstrip and slot line are λm/4 and λs/4 at the center of the cross section of the microstrip and slot line. In order to get broad bandwidth antenna characteristics, the tapered length is chosen as 4λ? and termination width is chosen as 1.75λ?. Experimental results show that the microstrip tapered slot antenna has symmetrical E- and H-plane beam patterns with around 5㎓ of bandwidth at center frequency of 5.0㎓.
전자기 전달관계를 이용한 원통형 직선 왕복구동 액추에이터의 전자기 특성 해석 및 실험
장석명(Seok-Myeong Jang),김현규(Hyun-Kyu Kim),최장영(Jang-Young Choi),이성호(Sung-Ho Lee) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.4
This paper deals with the thrust calculations and the measurements of a cylindrical Linear Oscillatory Actuator (LOA) sing Transfer Relations Theorem (TRT), namely, Melcher's methodology. Using transfer relations derived in terms of a magnetic vector potential and a two-dimensional (2-d) cylindrical coordinate system, this paper derives analytical solutions for the magnetic vector potential, magnetic fields due to Permanent Magnets (PMs) and stator winding currents and the thrust. The analytical results are validated by non-linear Finite Element (FE) analyses. In particular, test results such as thrust and back-emf measurements are given to confirm the analysis.
설계 변수에 따른 리니어 스위치드 릴럭턴스 전동기의 힘특성 해석
장석명(Seok-Myeong Jang),박지훈(Ji-Hoon Park),최장영(Jang-Young Choi),유대준(Dae-Joon You),고경진(Kyoung-Jin Ko),성호경(Ho-Kyung Sung) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.4
This paper deals with extraction of design parameters of Linear Switched Reluctance Motor (LSRM) based on force calculation using space harmonic analysis, 2D Finite Element Method (FEM) andexperimental measurement. First, analytical solutions for flux density due to mover winding currents are derived in terms of magnetic vector potential and a 2D rectangular coordinate system, for the case when the mover is located at aligned and unaligned position. The analytical results are compared with those obtained from a 2D FEM. Second, using Fourier series expansion. this paper predicts the force profile of LSRM analytically.
장호수(Jang, Ho-Su),문석기(Moon, Seok-Ki) 백산학회 2012 白山學報 Vol.- No.92
선사시대는 오늘날과는 매우 다른 자연환경이었고, 특히 구석기시대는 생태환경이 주기적으로 급격히 변했던 시기이다. 따라서 구석기시대를 이해하는데 생태환경에 대한 이해가 필수 요소이다. 이 글에서는 구석기유적을 정비 • 복원하는 방법의 하나로 역사생태공원을 조성하는 방안에 대하여 제시하였다. 역사 생태공원은 역사공원과 생태공원을 접목하는 새로운 형태의 것으로 유적의 역사적 가치와 생태적 가치를 함께 고려하여 조성함으로서 유적 보존과 함께 교육적 목적을 달성하기 위한 수단이 된다. 연구 대상 유적은 단양 수양개유적을 선택하였고 생태환경 복원을 위한 자료들은 제천, 단양 일대 구석기시대 유적에서 나온 생태자료들을 함께 활용하였다. 유적의 정비 복원은 보존을 전제로 하므로 생태복원 과정에 현존 식생을 보존하면서 현장에 고생태환경 자료를 근거로 하여 일부 식생을 복원하는 방식을 제시하였고, 동물상은 현재 살지 않는 동물들이 많으므로 모형으로 제작 전시 연출하거나 부족한 부분은 실내 전시에서 유물 전시와 영상 복원 등의 방법을 시용하도록 하였다. 구석기유적의 정비•복원은 현장 재현과 실내 전시를 병행하여 재현 효과를 높이고 교육적 활용이 가능하도록 해야 할 것이다. This study is focused upon making Paleolithic site into historic theme park through ecological restoration. Paleolithic era is much different ecological condition compared with these days. And there left not much historic remains than ecological sources in most Paleolithic sites, restoring Paleolithic site into ecological park is thought to be more reasonable for the purpose of conserving sites and remains. The first step of restoring Paleolithic site is reconstructing environmental background in which they earned a living with their own life style at that time. There are three ways of ecological restoration for prehistoric sites, which are the reclamation, the rehabilitation, and the restoration. The reclamation requires physical modification, and the rehabilitation does biological modification, but only the restoration requires improved management. Among them, the most desirable way applicable upon the Paleolithic site restitution is the reclamation. Suyanggae man, occupied namhangang river bed mainly upper paleolithic period, lived in wet prairies condition with roaming deer, roedeer, wild rabbit. They equipped with arrowhead made of tanged point and microblade tools. The first step of restoring Paleolithic site is reconstructing environmental background in which they earned a living with their own life style at that time. and most of all the purpose of making paleolithic site into historic theme park is understanding their way of life.
장석명(Seok Myeong Jang),박지훈(Ji Hoon Park),최장영(Jang Young Choi),유대준(Dae Joon You),성호경(Ho Kyung Sung) 대한전기학회 2007 대한전기학회 학술대회 논문집 Vol.2007 No.4
This paper deals with design of high speed linear switched reluctance motor(LSRM). First, we derived design factor from pole arc ratio of stator and mover, and calculated time constant using inductance and resistance. Second, we decided design parameter from design factor using time constant. Finally, analyze characteristics for LSRM using finite element analysis