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論文 |
論文
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福室, 允央 ; 大関, 健一郎 ; 斎藤, 正人 ; 葛, 徳梁 ; 村上, 岩範 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />A simple and stable energy-storage flywheel system with high temperature superconducting levitation is presented. In order to have stable levitation, a superconductor and a permanent magnet are
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used, and 3 permanent magnets support the top of the shaft. In the part of drive system, 8-poles permanent magnet and 8 coils are used to cancel electromagnetic forces in the radial direction. An electromagnetic damper consisting of permanent magnet for levitation and 4 coils is presented which lies at both ends of the shaft. When the shaft vibrates in the direction perpendicular to the shaft axis, current flows in the damper coil. It generates the electromagnetic force. The force is in proportion to vibration frequencies of the shaft, so that the force behaves like damping forces. Using this system, a control like the sensorless control is performed. Experimental tests have been carried out for the system as just mentioned. It is clarified that our system has stable levitation, and vibrations are suppressed significantly.
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論文 |
論文
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長屋, 幸助 ; 林, 乃生幸 ; 大関, 健一郎
概要:
application/pdf<br />Journal Article<br />This article presents a new levitation technique, which uses a small superconductor and a set of permanent magnets. In the system, a small superconductor is connected to the bottom of the vertical
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shaft. The gravity force and axial vibration force are supported by the superconductor. A circular permanent magnet is attched to the top of the shaft, and the other circular permanent magnet lies at the frame. The N-pole of one of the magnets faces to the S-pole of the other magnet, so a drag force acts between the magnets. The drag force is unstable in the axial direction, but the pinning force in the axial direction of the superconductor makes it stable. There is a restoring force in the horizontal direction between two permanent magnets, and in addition, there is a pinning force of the superconductor, so that both ends of the shaft are stable in the horizontal direction. This implies that the levitated shaft is stable without control. In general, controls have to be made in either axial or horizontal direction when the ordinary magnets are used. The levitation technique presented in this paper has advantages, Because, in order to have stable levitation, only one small superconductor is required, and a cooling system is simple. A method for passing through the critical speeds is also presented. In the method, rotating conductor disc is used to have the electromagnetic damping. Both the analysis and experiment are presented.
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