An augmented circuit model for magnetic bearings including eddy currents, fringing, and leakage

Magnetic bearings are often designed using magnetic circuit theory. When these bearings are built, however, effects not included in the usual circuit theory formulation have a significant influence on bearing performance. Two significant sources of error in the circuit theory approach are the neglect of leakage and fringing effects and the neglect of eddy current effects. This work formulates an augmented circuit model in which eddy current and flux leakage and fringing effects are included. Electrical impedance predictions from the model are found to be in good agreement with experimental data from a typical magnetic bearing.