Modeling of Switching Ripple Currents (SRCs) for magnetic bearings including eddy current effects

In magnetic thrust bearings (MTBs), eddy currents induced in the solid stator and thrust disk not only result in performance degrading of the bearing, but also influence the SRC of the coil when driven by a switching power amplifier. In this paper, a fractional differential equation (FDE) model of the SRC considering the effects of eddy current is proposed and a numerical solution can be obtained from it by a predictor-corrector algorithm. Results from finite element method (FEM) and experiments show its validity. The presented model can be applied to the studies of self-sensing of non-laminated magnetic bearings.