• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권3호
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• pp.135-142
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• 2004

In this paper, the magnetic circuit characteristics and the current/torque analysis of a Spoke Type permanent magnet motor have been researched, compared with the SPM Type motor. In the magnetic circuit analysis, the characteristic of air-gap flux density has been analyzed according to the variation of the number of pole and the ratio of magnet height to arc length using finite element method and circuit equations. Moreover, the electromagnetic and the reluctance torque have been analyzed by the current profile, which is obtained from the variation of turn-on angle, and these informative data has been utilized for the overall characteristics of the Spoke Type BLDC motor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1019-1020
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• 2011

This paper deals with torque analysis of axial flux permanent magnet (AFPM) type eddy current brake (ECB) based on analytical field computation. On the basis of a magnetic vector potential and a two-dimensional (2-D) polar coordinate system, analytical solutions for normal and tangential flux density due to permanent magnet (PM) considering eddy current effect are obtained. And then, using derived analytical field solutions, braking torque and normal force characteristics according to rotor speed are also predicted. A three-dimensional (3-D) finite element (FE) analysis is employed to confirm the validity of analyses.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.59-61
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• 2006

The single phase switched reluctance motor(SRM) is simpler in control circuit because the number of switching devices is fewer than the poly phase SRM. The energy density per unit volume is very big because all stator poles are excited simultaneously by a single switching power source. But it must be provided a starting device on account of not being generated the starting torque at specific rotor positions. And also it has some demerits that have a torque ripple, noise and vibration because of being excited by switching pulse power source. Therefore, to make up for these demerits, it is realized many studies for the structure design used by computer and the operating methods by power electronics technique. In this paper, we'll present the comparison of the single phase SRM with the various rotor pole face types, as like stepped rotor pole face type and general rotor pole face type. For the torque characteristics analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.122-124
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• 2003

This paper deals with the magnetic field analysis and compution of cogging torque using an analytical method in high speed brushless motor/generator. The magnetic field is analyzed by solving space harmonics field analysis due to magnetizing distribution and the cogging torque is analyzed by combining field analysis with relative permeance.

• 전기학회논문지
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• 제65권1호
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• pp.58-64
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• 2016

In this paper, the design of rotor shape was performed for improvement of start-up characteristics and efficiency in single-phase LSPM. In order to improve the start-up characteristics, shape of rotor aluminium cage bar was changed. Through arrangement of permanent magnets and installation of flux barriers, it was performed torque ripple reduction and efficiency improvement. Cogging torque and back-EMF is calculated by the no-load analysis, start-up time is calculated by the start-up state analysis, efficiency and torque ripple is calculated by steady state analysis. The characteristics of the motor were calculated through FEM.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.139.1-139
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• 2001

Nowadays due to the remarkable advance of power electronics and micro controller, a Brushless AC servomotor which has the characteristics of the high inertia to torque ratio, the high power density, the maintenance free, and so on is being used widely in industrial robots, machine tools, and factory automation. In a conventional DC motor, the polarity commutation is performed of itself by mechanical brush and commutator, but the PM synchronous motor requires an electrical commutation according to the rotor position. Then for the maximum torque production PM synchronous motor has to be equipped with a controller which maintains the optimal phase angle between the stator field and the magnetic field ...

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.669-670
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• 2015

In this paper, rotor design modification of a novel proposed machine termed the Axial Flux Doubly Fed Reluctance Machine (AF-BDFRM) is studied. The main potential advantage of AF-BDFRM is that it has larger torque and power density compared to radial flux-BDFRM. However, with the general rotor pole shape, this machine output back EMF has high THD % and high cogging torque. This paper studies the rotor design modification in the proposed AF-BDFRM to reduce the THD % in inducedd back EMF and cogging torque. Also the transient 3D finite element analysis (FEA) optimization of initial design is presented.

• 한국분무공학회지
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• 제7권1호
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• pp.1-6
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• 2002

This study has focused on using fuel injections as variables for measuring performance and reducing exhaust gas in turbo-charger diesel engine. In experiments, we changed nozzle hole diameter, diameter of an injection pipe, and injection timing as variable. The results show that torque. fuel consumption and smoke are reduced as nozzle hole diameter decreases, while NOx increases. When the diameter of injector is reduced, torque, fuel consumption and smoke are deteriorated, but NOx is decreased. In addition, when the time for injection is advanced. torque, fuel consumption and smoke are improved, but the density of NOx is increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.18-20
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• 2004

An interior permanent magnet synchronous motor (IPMSM) is receiving increased attention for many industrial applications because of its high torque to inertia ratio, superior power density, and high efficiency. IPMSM is necessary to use the accurate information of the inductace for the precise torque control owing to the reluctance torque. This paper presents two method to measure the each-axis inductance. The first method uses the peak current that is measured by applying the pulsewise voltage on the each position of IPMSM. The second uses the hysteresis loop of the flux and current measured by applying the positive and negative pulsewise voltage alternately on the each-axis.

• Journal of Magnetics
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• 제18권4호
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• pp.432-442
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• 2013

For magnetically suspended flywheel (MSFW) with gimballing capability, demerits of Lorentz force-type magnetic bearings and common reluctance force-type magnetic bearings are analyzed, a novel reluctance forcetype magnetic bearing (RFMB) including radial and axial magnetic bearing units with 4 separate biased permanent magnets and two conical stators is presented. By equivalent magnetic circuits' method, its magnetic properties are analyzed. To reduce the eddy loss, it was designed as radial poles with shoes and its rotor made of Iron-based amorphousness. Although the uniformity of magnetic flux density in the conical air gap determines mainly the additional tilting torque, the maximum additional tilting torques is 0.05Nm and the rotor tilting has no influence on its forces when the rotor tilts or the maximum changes does not exceed 14% when the rotor drifts and tilts simultaneously. The MSFW with this RFMB can meet the maneuvering requirement of spacecraft theoretically.