• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권11호
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• pp.564-571
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• 2006

In this paper, the estimation of Z-axis thrust ripple and vibration of BLDC motor with asymmetrical permanent magnet overhang is performed by 3-D Finite Element Method (3-D FEM) and vibration experimentation. The ripple of Z-axis thrust is due to armature reaction field in BLDC motor driven to squire wave. That is generating to Z-axis vibration. The analysis results of Z-axis thrust and the vibration by Z-axis thrust ripple is validated by comparison with experimental result.

• 한국기계가공학회지
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• 제20권3호
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• pp.122-128
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• 2021

Machining operations require removal of chips to keep the coolant clean and fresh throughout the operation time. In this study, microchip removal equipment was developed using AutoCAD and CATIA programs for 3D modeling and 2D draft. In addition, the flow analysis and electromagnetic field analysis of the equipment were performed using the COMSOL Multiphysics program. The flow design of the coolant oil tank was realized on the basis of fluid analysis results. Further, on the basis of magnetic density analysis, a conveyer was designed for effectively removing metal microchips in the tank by using arrays of neodymium permanent magnets.

• 전기학회논문지
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• 제58권7호
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• pp.1321-1328
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• 2009

In this paper, an electromagnetic force driving actuator (EMFA) and three-link mechanism are proposed as a driving mechanism and connection device for low voltage air circuit breaker (ACB). As the result of dynamic characteristic analysis, the actuator and link mechanism are designed from the simulation and manufactured. The magneitc field of the EMFA is analyzed using the finite element method (FEM). The dynamic characteristic analysis with calculation of the circuit equation and kinetical equation is performed by the time difference method (TDM). Also, the result of the analysis is verified through the experiment of the fabrication model. In this paper, the EMFA size is smaller than the actuator for high voltage circuit breaker. Thus, the dynamic characteristic is analyzed with end-winding inductance that is calculated by the same method which is applied on the circle type end-winding of motors. The designed model for 1600 ampere-frame ACB and the three-link mechanism for connecting contact part with actuating part are manufactured. It is confirmed that the three-link mechanism is possible for improving the circuit breaker efficiency and reducing the size of the EMFA. It is proved that the improved 2-D analysis is more accurate than established method.

• 한국CDE학회논문집
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• 제21권4호
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• pp.409-416
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• 2016

This study aims to investigate dynamic interaction characteristics between Maglev train and 3 span continuous guideway. The integrated model including a 3D full vehicle model based on multibody dynamics, flexible guideway by a modal superposition method, and levitation electromagnets with the feedback controller is proposed. The proposed model was applied to the Incheon Airport Maglev Railway to analyze the dynamic response of the vehicle and guideway from the numerical simulation. Using field test data of air gap and guideway deflections, obtained from the Incheon Airport Maglev Railway, the analysis method is verified. From the results, it is confirmed that Maglev railway system are designed and constructed safely according to the design criteria.

• 전자공학회논문지
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• 제50권2호
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• pp.47-53
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• 2013

본 논문에서는 SATA(Serial Advanced Technology Attachment) 커넥터의 차동 임피던스 계산 방법을 적용하여 설계 변경 방법을 제안하고 신호 전달 특성을 개선하였다. 3차원 FEM(Finite Elements Method) 전자기장(Electromagnetic Field) 시뮬레이터를 이용하여 SATA 커넥터의 차동 모드 S-파라미터를 계산하고, 신호 전달 특성을 분석한다. 차동 임피던스는 Odd mode 임피던스를 이용하여 계산되므로 인덕턴스, 커패시턴스, 상호 인덕턴스, 상호 커패시턴스 값이 필요하다. 따라서 시뮬레이터를 이용하여 SATA 커넥터의 각각의 값을 추출하여 차동 임피던스를 계산하였고, 이 값은 $107.3{\Omega}$으로 설계 사양을 만족하지 못하였다. 신호 전달 특성 개선을 위해서 SATA 커넥터의 핀을 $d_x$, $d_y$ 방향으로 설계 변경하고, 각 경우의 신호 전달특성과 차동 임피던스를 분석하였다. $d_y=0.1mm$의 경우에서 신호 전달 특성이 가장 우수하게 나타났고, 차동 임피던스가 $98.7{\Omega}$으로 정합되었다. 이때, 반사손실은 1.5 GHz에서 15 dB 개선되었다.

• 소성∙가공
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• 제23권7호
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• pp.431-438
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• 2014

For electromagnetic forming(EMF) the most important feature is a forming coil which creates the electromagnetic force(Lorentz force), using current density and a magnetic field. Most previous papers have concentrated on the final configuration of the blank or the efficiency of EMF process. Studies focused on the design parameters affected by the forming coil performance have not been conducted. In order to design a suitable forming coil for an object, the current study uses LS-DYNA EM-Module to not only optimize the coil but also to examine the effect of coil performance. By this method a suitable forming coil was made and tested to determine whether or not good formability was achieved in a free bulge test Numerical analysis was also used. The workpiece was Al 1100-O with a thickness of 1.27mm and the coil was made from copper CW004A, which has good electrical conductivity and is suitable for electrical components.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.415-417
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• 2003

we analyzed the electromagnetic behavior of a superconducting fault current limiter (SFCL) under the quench state using FEM. The analysis model used in this work is 5.5 KVA meander-line type SFCLs. Meshes of 3,650 triangular elements were used in the analysis of this SFCL. Analysis results showed that the distribution of current density was concentrated to inner curved line in meander-line type-SFCL and the maximum current density was 14.61 $A/m^2$ and also the maximum Joule heat was 2,030 $W/m^2$ in this region. We think that the new and the modified structure must be considered for an uniform distribution of the electromagnetic field.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.661-662
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• 2006

On the contrary of a conventional motor with very narrow air-gap, it is difficult to calculate the accurate magnetic field distribution and the performance of an air-cored superconducting motor by 2 dimensional analysis, which does not use high permeability material except outer machine shield. This paper aims to do analysis of magnetic field and force distribution from the 3 dimensional modelling of a 1MW class superconducting synchronous motor. Especially, the field coil composed of Bi-2223 high-temperature superconductor and the outer machine shield are modelled by finite element analysis software according to their structures and the self-inductance and Lorentz force are calculated based on the 3 dimensional magnetic field calculation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마연구회
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• pp.19-22
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• 2003

In this paper, we performed analysis of electric field, magnetic field, current density in AMF electrode using the Maxwell 3D simulation. The current distribution and magnetic field in simple models are analyzed to verify its efficiency and accuracy. In the vicinity of the slits of axial magnetic field type electrode a comparatively high axial magnetic flux density existsIn addition the validity of FEM is confirmed by performing the analyses of distribution in current density and magnetic flux density.

• 조명전기설비학회논문지
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• 제22권3호
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• pp.59-65
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• 2008

High-speed electrical motor has been studied for several applications, i.e. for direct-drive systems of centrifugal compressors and turbo blowers. This paper deals with a design consideration of electromagnetic, mechanical and thermal limits of high-speed induction motor for turbo blower. Basic design concept of high-speed motor was proposed. As the motor is to be operated at high speed, the losses are quite different from conventional low-speed machines. Especially, the increases of rotor eddy current and friction losses could lead to an overheated motor. So, we suggested a special cooling system to reduce temperature rise. And, based upon this design concept, the prototype induction motor(37[kW], 45,000[rpm]) for high-speed turbo blower was designed and 2-D electromagnetic field analysis was implemented. Finally, criteria to evaluate the characteristics of high-speed induction motor have been proposed and tested.