Minimizing Eddy Current Effects in a Hybrid Thrust Magnetic Bearing

Hybrid magnetic bearings are often used to eliminate power losses due to the bias current. However, in dynamic conditions, the bias flux and the control flux vary, thus inducing eddy currents in the iron core which cause power losses and affect the performance of the bearing. These eddy current effects can be reduced by segmenting the stator to break the eddy currents' loop. The model of Hybrid Thrust Magnetic Bearing (HTMB) studied in this paper was cut into 2, 4, and 8 segments, and then a 3D-FEM analysis was performed for each configuration at different frequencies. The results present a maximum reduction in eddy current losses of about 66% between a 2-segment and the uncut HTMB. In addition, the improvement of dynamic force was observed for all bearing configurations. The maximum value of 6.3 N was recorded at 2 kHz on a 2-segment HTMB.