Passive magnetic bearings offer significant advantages relative to common active magnetic bearings, such as simple, robust, and efficient structure. Permanent magnet (PM) passive magnetic bearings are composed of opposing magnet rings on rotor and stator. Although their stiffness has been improved using alternating or Halbach magnetisations in many previous studies, they still suffer from lack of damping force. In this study, the optimal design is focused on a combination of PM bearing and eddy current damper by adding a conductive layer along the magnets of the stator or rotor. This will moderate the magnetic material consumptions; thereby, the cost and overall size of the bearing are reduced. A complete analytical method is performed to calculate the stiffness and axial, radial, and rotating damping coefficients. The accuracy of the analytical model is estimated quantitatively using 3D finite element method simulations. Moreover, all of the parameters are normalised and optimised for maximum stiffness and damping.

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Optimal design of a compact passive magnetic bearing based on dynamic modelling

References

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