Affiliations: [a] Science and Technology on Inertial Laboratory,
Fundamental Science on Novel Inertial Instrument and Navigation System
Technology Laboratory, Beihang University, Beijing, China
Correspondence:
[*]
Corresponding author: Yun Le, Science and Technology on Inertial
Laboratory, Fundamental Science on Novel Inertial Instrument and Navigation
System Technology Laboratory, Beihang University, Beijing 100191, China. Tel.:
+86 010 82339057; E-mail: zazuly@163.com
Abstract: A hybrid radial magnetic bearing (HRMB) with permanent magnet
creating bias flux is used to reduce the power consumption. Laminated cores are
widely used in HRMB to reduce eddy currents. Nevertheless, when the frequencies
of rotation and control currents are extremely high, eddy-current effects in
laminated iron cores still have a significant influence on the behavior and
performance of magnetic bearings. In order to predict performance and guide
design of the HRMB system in high frequency, an analytical method based on
equivalent circuit model whose parameters are frequency-dependent is used in
this paper. The analytical results show that, the eddy currents induced due to
rotor movement and dynamically changing control currents will result in
considerable magnitude decrease and phase lag of bearing stiffness.
Furthermore, the eddy current effect on HRMB can be reduced by increasing the
air gap, decreasing the laminations thickness and decreasing the laminations
conductivity. Finally, a prototype is designed and fabricated; the experimental
results demonstrate the validity of the analysis.
Keywords: Hybrid magnetic bearing, dynamic stiffness, laminations, equivalent conductivity
