• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.130-131
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• 2007

본 논문에서는 자기포화특성이 두드러진 매입형 영구자석 동기전동기의 특성해석, 설계 및 제어에 응용할 수 있는 통합변수인 d-q축 쇄교자속(Flux Linkage)의 추출에 대하여 나타낸다. 특히, 영구자석과 전기자전류에 의한 Cross-Magnetization을 고려한 특성을 유한요소법(F.E.M)을 통하여 나타내며, 제작된 시작기 실험을 통하여 제안된 추출기법의 타당성을 나타낸다.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.40-42
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• 1998

Magnetization distribution in the ring magnet for BLDC motor is generally nonuniform because the structure of mutipole magnetizer is not symmetry and the air gap is not uniform. In this paper, the effect of the nonuniform magnetization on characteristics of the motor such as torque ripple, unbalanced force and current is examined. Time stepped finite element method is used for electromagnetic field analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.125-132
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• 2013

This paper has done a three-dimensional FEM analysis of the PM claw pole stepping motor. As magnetization happens in the z-axis, which does not have a constant value, three-dimensional FEM analysis is necessary for characteristic analysis of PM claw pole stepping motors. Because it is a type of permanent magnet motor, the PM claw pole stepping motor naturally has a detent torque. This torque is known to show negative effects on motor performance. To improve motor performance, reducing the detent torque is very important during the motor design. This paper applied DOE for optimization of stator pole design of the motor. Also, we compared motor performance by applying a different type of rotor shape, dividing the permanent magnet. To verify the simulation results, an experiment was done.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.5
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• pp.70-75
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• 2014

Permanent magnets have recently been considered as device that can be used to control the behavior of mechanical systems. Neodymium magnets, a type of permanent magnet, have been used in numerous mechanical devices. These are permanent magnets made from an alloy of neodymium, iron, and boron to form the Nd2Fe14B tetragonal crystalline structure. The magnetic selection, magnet core design and mechanical errors of the magnetic component can affect the performance of the magnetic force. In this study, the coercive force, residual induction, and the dimensions of the design parameters of the magnet core are optimized. The design parameters of magnet core are defined as the gap between the magnet and the core, the upper contact radius, and the lower thickness of the core. The force exercised on a permanent magnet in a non-uniform field is dependent on the magnetization orientation of the magnet. Non-uniformity of the polarization direction of the magnetic has been assumed to be caused by the angular error in the polarization direction. The variation in the magnetic performance is considered according to the center distance, the tilt of the magnetic components, and the polarization direction. The finite element method is used to analyze the magnetic force of an optimized cylindrical magnet.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.2
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• pp.168-172
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• 2005

A novel cogging torque reduction algorithm is presented for 2-pole permanent magnet DC motor. While the shape of the permanent magnet is changed in the conventional method, the pole shape of the magnetizing yoke is optimized in the presented algorithm. In order to parameterize the shape of the yoke, and the distribution of the residual magnetization of the permanent magnet, the Bezier spline is used. The shape of the magnetizing yoke is optimized using the design sensitivity analysis incorporated with the finite element method and Bezier spline.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.5
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• pp.167-172
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• 1984

This paper describes the finite element analysis of magnetostatic field problems with permanent magnets. Two kinds of algorithms, one using the magnetic vector potential and the other using the magnetic scalar potential, are introduced. The magnetization of the pemanent magnet is used as the source instead of the magnetic equivalent current in both of the formulations using the magnetic vector potential and the magnetic scalar potential. A simple functional, which has only the region integral instead of the region integral and boundary integral, is derived in the formulation using the magnetic scalar potential. These make the formulation of the system equations simpler and more convenient than the conventional methods. The numerical results by the two proposed algorithms for a C-type permanent magnet model are compared with the analytic solutions respectively. The numerical results are in good agreement with the analytic solutions.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.235-243
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• 1998

For motor operation at low speeds and loads, torque pulsation by the cogging torque is often a source of vibration and control difficulty. In this paper, the magnetic field of a motor is calculated by finite element method. The periodic cogging torque is determined using Maxwell stress method and time stepping method, and then decomposed using fourier series expansion, The purpose of this paper is to characterize design parameters on the cogging torque and to design a permanent magnet motor with a cogging torque less vulnerable to vibration, without sacrificing the motor performance. The design parameters include stator slot width, permanent magnet slot width, airgap length and magnetization direction. A new design with a less populated frequency spectrum of the cogging torque is proposed after characterizing individual effect of design parameters. Magnet pole edge shaping, by gradually increasing the cogging torque with reduced higher harmonics.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.609-611
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• 2008

Eddy current is usually generated in material with high conductivity by time-varying source such as AC current and also is induced in the moving source with relative velocity. The contactless magnetic brakes make use of the braking force from the eddy current generated by moving source and currently used for the secondary brakes of heavy trucks, buses and rail vehicles. This study aims to design the magnetization pattern of a permanent magnet type eddy current brake system to maximize the braking force. The analysis of the brake system is based on the two-dimensional finite element analysis. We use the sequential linear programming as the optimizer and the adjoint variable method for the sensitivity analysis.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.3-5
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• 2005

This paper presents a analysis solutions for the general class of iron-cored Permanent Magnet Linear Synchronous Motor(PMLSM) with vertical topologies. In our design and analysis, rotor consisting of permanent magnets and slot less iron-cored coil stator are treated in a uniform way via vector potential. For one such motor structure, we give analytical formulas for its magnetic field by permanent magnet and current coil and variation of the Back-EMF and magnetization inductance according to coil turns.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.658-663
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• 2009

Eddy current is usually generated in the material with high conductivity by time-varying source such as AC current and also is induced by the moving source with relative velocity. The contactless magnetic brake makes use of the braking force from the eddy current generated by the moving source and currently used for the secondary brakes of heavy trucks, buses and rail vehicles. This study aims to design the magnetization pattern of the eddy current brake system of a permanent magnet type where the design aim is to maximize the braking force. The analysis of brake systems is based on the two-dimensional finite element analysis. We use the sequential linear programming as the optimizer and the adjoint variable method is applied for the sensitivity analysis.