Dynamical Electromechanical Model for Magnetic Bearings Subject to Eddy Currents

Eddy-current forces may play a significant role in magnetic bearings. They generate losses and unpredicted forces, which may lead to a malfunction of the bearing. But eddy currents in magnetic bearings may also be used positively, to generate desired forces, like in electrodynamic bearings. This paper presents a model able to predict, analyze, or simulate the dynamical behavior of any rotating magnetic bearing in which classical eddy-current forces arise. This model integrates the mechanical aspects linked to the rotor dynamics and the electrical aspects linked to the electromagnetic nature of the forces. This paper explains how the parameters of the model can be identified on the basis of quasi-static finite element method (FEM) or experiments. The validation of the model is done by comparison with FEM results on an electrodynamic radial bearing.