Energy Storage Science and Technology ›› 2021, Vol. 10 ›› Issue (5): 1656-1666.doi: 10.19799/j.cnki.2095-4239.2021.0258

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Research on synchronous damping around the critical bending speed of magnetic bearings

Yating LIU(), Kai ZHANG(), Yang XU   

  1. The Department of Engineering Physics, Tsinghua University, Beijing 100084, China
  • Received:2021-06-08 Revised:2021-07-11 Online:2021-09-05 Published:2021-09-08
  • Contact: Kai ZHANG E-mail:lyt17801050098@163.com;zhangkai@mail.tsinghua.edu.cn

Abstract:

Recently, magnetic bearing systems have undergone development to induce higher speed and better reliability in such systems. This has led to the rotor speed exceeding the first-order bending critical speed. However, due to insufficient damping at a critical frequency, magnetic bearing systems face instability risks. In order to adapt the system's performance and stability around the first-order critical speed, this paper proposes a synchronous damping method to provide the damping required for the rotor to cross the critical speed and to support it in reaching a higher yet stable speed. With a rotor modal constructed using the classic finite element method and combining the modal separation method and mass discretization, the suppression of unbalanced vibration around the first-order critical speed using the synchronous damping method was verified in detail. This result can serve as a foundation for the practical application of the synchronous damping method. Finally, with the addition of the synchronous damping module in the existing magnetic bearing equipment in a laboratory setting, the rotor steadily transited the first-order bending speed of 45,000 r/min, which verified the effectiveness of the synchronous damping method in supporting the flexible rotor to pass through the critical speed.

Key words: magnetic bearing, unbalance control, flexible rotor, critical speed, synchronous damping

CLC Number: