Resonant amplitude reduction of a rotor supported by a superconducting magnetic bearing with an axial electromagnet

Hiromu Sasaki, Yu Yubisui, Toshihiko Sugiura

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Superconducting magnetic bearings (SMBs) have various merits because of noncontact stable levitation. However, SMBs tend to make the rotor amplitude larger near a critical speed because of their low damping. Furthermore, complicated vibrations can be caused due to the nonlinearity of the electromagnetic force. Therefore, it is necessary to reduce the amplitude by considering the effect of the nonlinearity on dynamics during passing through the critical speed in applications. In this paper, we investigate resonant amplitude reduction of a rotor supported by an SMB using axial translation of the rotor. For this purpose, we first introduced an analytical model consisting of an SMB, a permanent magnet, and an electromagnet (EM) that can translate a rotor in the axial direction. We then examined the effect of exerting electromagnetic force at an appropriate rotational speed on amplitude reduction of a rotor. Numerical results show that considerable reduction of the resonant amplitude can be achieved by switching the EM at a proper rotational speed both in steady-state response and in transient response. We also carried out experiments. Steady-state responses were measured with changing the distance between the superconducting bulk and the rotor, magnetic induction of the EM, and so on. Experimental results show qualitative agreement with numerical ones, which verifies the effectiveness of the proposed method of amplitude reduction. We further discussed effect of nonlinearity of electromagnetic forces on amplitude reduction.

Original languageEnglish
Article number6994264
JournalIEEE Transactions on Applied Superconductivity
Volume25
Issue number3
DOIs
Publication statusPublished - 2015 Jun 1

Fingerprint

magnetic bearings
Electromagnets
electromagnets
Magnetic bearings
rotors
Rotors
critical velocity
nonlinearity
electromagnetism
Electromagnetic induction
magnetic induction
levitation
Transient analysis
transient response
Permanent magnets
Vibrations (mechanical)
Analytical models
permanent magnets
Damping
damping

Keywords

  • Electromagnets
  • High-temperature superconductors
  • Nonlinear dynamical systems
  • Rotors

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Resonant amplitude reduction of a rotor supported by a superconducting magnetic bearing with an axial electromagnet. / Sasaki, Hiromu; Yubisui, Yu; Sugiura, Toshihiko.

In: IEEE Transactions on Applied Superconductivity, Vol. 25, No. 3, 6994264, 01.06.2015.

Research output: Contribution to journalArticle

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