• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1025-1033
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• 2006

This paper describes the levitation mechanism using magnetic wheel for a maglev planar transportation system. Rotation of the magnetic wheel where the permanent magnet array is embedded produces the time varying traveling magnetic flux density and the generated magnetic flux density creates the induced levitation force and drag force with the conductor. Because the net drag force is zero, magnetic wheel can only generate the levitation force. Thus, it always guarantees the stability in levitation direction and it does not disturb other directional motion. In this paper, levitation principle of the magnetic wheel is analyzed using distributed field approach and dynamic characteristics of the levitation in the magnetic wheel system are estimated. The feasibility of the proposed levitation mechanism is verified through the several experimental works.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.4
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• pp.213-216
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• 2006

The magnetic levitation effect a high Tc superconductor beneath the toroidal permanent magnet was examined by means of a improved magnetic seesaw method. Magnetic effects associated with penetration and pinning in superconductor. One of these was focussing of magnetic field by superconductor and the other was magnetic levitation. The existence of equilibrium was shown to be related to hysteresis observed in the force separation for a toroidal permanent magnet and superconductor. Obtained results indicate that magnetic levitation effect in the present case was mainly due to diamagnetic effect.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.557-561
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• 2016

Recently, in the manufacturing process of flat panel displays, mass production methods of inline system has been emerged. In particular the next generation OLED display manufacturing process, horizontal inline evaporation process has been tried. It is important for the success of OLED inline evaporation process to develop a magnetic levitation transport system capable of transferring a carrier equipped with a mother glass with high accuracy without any physical contact along the rail under vacuum condition. In the case of existing wheel-based transfer system, it is not suitable for OLED evaporation process requiring high cleanliness. On the other hand, the magnetic levitation transport system has an advantage that it does not generate any dust and it is possible to achieve high-precision control because there are not non-linear factors such as friction force. In this paper, we introduce the high-precision magnetic levitation transport system, which is currently under development, for OLED evaporation process.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.94-96
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• 2009

This paper deals with the design considerations of electro-magnet (EM)-permanent magnet (PM) hybrid levitation and propulsion device for magnetically levitated (maglev) vehicles. Several design considerations such as machine structure, manufacturing, and control strategy are described. In order to verify the design scheme and feasibility of control strategy, dynamic test set is implemented and tested.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.974-978
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• 2007

In this paper, the requirements of passive levitation for nonmagnetic body in magnetic fluid are investigated. The passive levitation system includes the electromagnetic system composed of two hollow solenoids, the magnetic fluid and the nonmagnetic body made of aluminum. The hollow solenoids generate nonuniform magnetic fields, leading to the gradient of the magnetic field in magnetic fluid. Hence, the resultant magnetic body force in magnetic fluid is used to levitate the nonmagnetic body in the opposite direction of the gravitation. The levitation conditions according to applied current and the mass of the nonmagnetic body are obtained analytically.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.686-691
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• 2005

State of the art and current issues related with the RC and PSC structure system for the magnetic levitation train were investigated. The German and China magnetic levitation train adopted a new kind of a structure to enable high-speed transportation, which allows the use of the space over a ground. The loading from magnetic levitation trains is light-weight compared with a regular train due to load distribution to a supporting structure. Therefore, the magnetic levitation train is considered an economical and efficient transportation system, and is also an environmentally-sustainable structure. In this paper, the structural design and construction technology specific to a magnetic levitation train were discussed, and structural considerations related with an actual operation of the train were pointed out. In addition, the future research area of a magnetic levitation train was proposed

• Progress in Superconductivity and Cryogenics
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• v.24 no.3
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• pp.52-56
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• 2022

Single-grain (c-normal or c-parallel) and multi-grain YBCO superconductors were prepared by a melt growth process with/without seeding. The magnetic levitation force and trapped magnetic field at liquid N₂ temperature (77 K) of the YBCO superconductors were investigated. Samples for the levitation force measurement were zero-field cooled (ZFC) to 77 K, and samples for trapped field measurement were field-cooled (FC) using Nd magnets. As for the magnetic levitation force, the c-normal, single grain sample showed the largest value, whereas the multi-grain sample showed the lowest value. The trapped magnetic field of the c-normal and c-parallel single-grain samples was 4-5 times that of the multi-grain sample. In addition, as the external magnetic field (the number of magnets) increased, the both properties increased proportionally. These results were explained in terms of the orientation dependence of the levitation forces and the magnetic field trapping capability of the YBCO superconductor.

• Journal of KSNVE
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• v.8 no.1
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• pp.195-203
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• 1998

The magnetic levitation system is utilized in the magnetic bearing of high-speed rotor because of little friction, no lubrication, no noise and so on. The magnetic levitation system need the feedback controller for the stabilization of system, and gap sensors are generally used to measure the gap. The use of sensor easily goes into troublesome caused by sensor failure discord between the measurement point and the control point etc. This paper presents the design of robust stabilizing contoller by $H_{\infty}$ control theory using the sensorless method proposed by authors in the magnetic levitation system. And we investigated both the validity of the designed controller and the usefulness of the sensorless magnetic levitation system through results of actual experiment.

• Journal of Power System Engineering
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• v.1 no.1
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• pp.144-153
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• 1997

The magnetic levitation system is utilized in the magnetic bearing of high-speed rotor because of little friction, no lubrication, no noise and so on. The magnetic levitation system need the feedback controller for the stabilization of system, and gap sensors are generally used to measure the gap. The use of gap sensors brings out the increase of the number of troublesome, and the decrease of the control performance because of the dislocation between the measurement point and the control point. This paper presents the design of the gap estimation circuit for the sensorless method proposed by authors in the magnetic levitation system. We made the gap estimation circuit which was composed of both the superposition circuit and the measuring circuit. And we investigated the validity of the usefulness of the proposed sensorless method in the magnetic levitation system through results of actual experiment.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.11
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• pp.1077-1085
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• 2007

Typically, three types of levitation technologies are applied to magnetic levitation systems: electromagnetic suspension, electrodynamic suspension, and hybrid electromagnetic suspension. A Halbach array is a special arrangement of permanent magnets which augments the magnetic field on one side of the device while cancelling the field to near zero on the other side. The application of this Halbach array magnet to the electrodynamic suspension has been recently studied in order to increase the levitation capability. This paper is focused on an analytical method of the magnetic levitation system using Halbach array magnet. The suitability of the proposed method is verified with comparing to the finite element method. In addition, dynamic stability of the magnetic levitation system is discussed. From this study, it is confirmed that the proposed method provides a reasonable solution with less computation time compared to the finite element method and the magnetic levitation system using Halbach array magnet is stable dynamically.