Parameter evaluation of a hybrid magnetic bearing by using 3D finite element analyses

The steady-state parameters such as electromagnetic forces and current stiffness of a permanent magnet biased active magnetic bearing with three poles are calculated by using finite element analyses. Since the arrangement of the permanent magnets cause a homopolar distribution of the magnetic field, a 2D model cannot be applied and consequently a 3D model has to be used. In order to achieve a fast computation environment, special attention is given to the modelling of different eccentric rotor positions. In particular, the paper discusses the influence of the rotor position on the electromagnetic bearing parameters to finally obtain a position-sensorless control algorithm of the hybrid magnetic bearing.