• Journal of Magnetics
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• v.20 no.4
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• pp.432-438
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• 2015

This paper presents an electromagnetic analysis of a tubular linear machine with axially magnetized permanent magnets using improved analytical techniques. Based on the magnetic vector potential and a two-dimensional polar-coordinate system, the magnetic field and armature reaction field can be derived. Using these, equivalent circuit parameters, such as the electromotive force and inductance, can be obtained analytically. Finally, the generating characteristics are derived with the equivalent circuit method. In this study, the finite element method was employed to provide a comparative evaluation, and experiments were conducted to validate the results of the analytical analysis.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.461-465
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• 2006

This paper presents a useful and simple method to design the passive skimming system for homogeneous permanent magnets based on numerical optimization. To simulate the effects of manufacturing and assembling tolerances, the actual geometrical parameter of the magnet with a derivation is suggested. Then, the optimal design model oi a passive shim system is set up to correct the derivative of field homogeneity. The numbers, sizes and locations of the passive shims are optimized by the steepest descent algorithm combined with design sensitivity analysis. Two implementations show that the proposed method can achieve the required homogeneity of the field with the minimum quantity of ferromagnetics.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.209-213
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• 1998

In the paper, we present the design procedure and analysis the fundamental characteristics for Linear DC Motor(LDM) using permeance method and finite element method (FEM). Designed LDM is made of two permanent magnets, three iron core and armature windings. For the design of the LDM, first of all it is necessary to calculate the air gap flux density and thrust force, after that to determine core size, the numbers of winding turns, winding width, etc. To demonstrate the method of caculation yields the right results, we used Maxwell program package for computing magnetic fields. Finally we find that the proposed design procedure in this paper is effective to design of LDM.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.22-24
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• 2005

This paper is intended to introduce a set of static and dynamic experiments for a better characterization of the linear permanent magnet oscillatory machine. The experiment have been peformed on two prototypes; one with buried permanent magnets with flux concentration while the other with surface permanent magnets. Though the testing arrangement allows for it, temperature, noise and vibration have not been in this paper.

• The Journal of Advanced Prosthodontics
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• v.4 no.4
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• pp.235-238
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• 2012

Facial prosthesis is generally considered over surgical reconstruction to restore function and appearance in patients with facial defects that resulted from cancer resection. Retention of the prosthesis is challenging due to its size and weight. Retention can be achieved by using medical grade adhesives, resilient attachments, clips and osseointegrated implants. It can also be connected to obturator by magnets. This clinical report highlights the rehabilitation of a lateral midfacial defect with a two piece prosthesis that included an extra oral facial prosthesis and an intraoral obturator with the use of magnets.

• Journal of Magnetics
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• v.22 no.1
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• pp.29-33
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• 2017

We report a micromagnetic numerical study on different quasi-crystal formations of magnetic vortices in a rich variety of dynamic transient states in soft magnetic nano-disks. Only the application of spin-polarized dc currents to a single magnetic vortex leads to the formation of topological-soliton quasi-crystals composed of different configurations of skyrmions with positive and negative half-integer numbers (magnetic vortices and antivortices). Such topological object formations in soft magnets, not only in the absence of Dzyaloshinskii-Moriya interaction but also without magnetocrystalline anisotropy, are discussed in terms of two different topological charges, the winding number and the skyrmion number. This work offers an insight into the dynamic topological-spin-texture quasi-crystal formations in soft magnets.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.965-967
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• 1993

In this paper, Take two perment magnets and three iron bars and wind copper wire around one or the bars. This paper demonstrate that the method or calculation yields the right results with MAXWELL-2D program package for computing magnetic field, also indicate the value to which the current in the coil has to be limited to prevent saturation of the iron or the cores. The Finally procedures for design of LDM are discussed.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.86-88
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• 1994

In this paper, we present the design procedure and analysis the fundamental characteristics for Linear DC motor using permeance method and finite element method. Designed LDM is made of two permanent magnets, three iron core and amateur windings. For the design the LDM, first of all it is nessary to calculate the air gap flux density and thrust force, after that to determine core size, the numbers of winding turns, winding width, motor cross section area and losses in the coil. Also, we analysis the fundamental characteristics for implemented LDM according to proposed design procedure, and we find that the implemented LDM generated constant thrust force for costant current as long as iron of core is not saturated. Finally, we find that the proposed design procedure in this paper is effective to design and implementation of LDM.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.199-207
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• 1998

This paper presents the design and the control of three degree-of-freedom(DOF) fine positioning device based on an electro-magnetic force. The device is designed by use of a magnetic circuit theory and it is capable of fine motion due to the electro-magnetic force. The device consists of permanent magnets, yokes and coils. The magnetic fluxes generated from the permanent magnets constitute magnetic paths through steel, whereas the coils are arranged into the gap between two surfaces of the yokes. Therefore, by supplying current to the coils, the coils are capable of some motions due to Lorentz forces. For the optimal design of the actuating system, the system parameters are defined and investigated under the given constraints. From the system modeling in small displacement, three decoupled equations of motion are obtained. To get better performance of the system, a PID controller is implemented. Experimental results are presented in terms of time response and accuracy.

• Journal of Magnetics
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• v.18 no.3
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• pp.297-301
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• 2013

Flux-reversal machine (FRM) is cost effective and suitable for mass production due to its simple structure. However, there is a notable permanent magnet flux leakage which deteriorates the performance. To compensate this drawback with a design method, an Inset-Permanent-Magnet-Type FRM (ITFRM) has been proposed. The ITFRM has permanent magnets perpendicular to the stator teeth surface, and thus, is much more difficult to demagnetize. In this paper, we deal with the iron losses and irreversible permanent magnet demagnetization characteristics of the ITFRM according to various design variables and driving conditions. To analyze the characteristics, a two-dimensional finite-element method (2D-FEM) considering nonlinear analysis of permanent magnets is used. As a result, we propose the design variables that have the largest effects on the iron losses and irreversible magnet demagnetization.