A FEM-based method dynamic analysis of a thrust magnetic bearing with permanent magnet bias

Abstract

Active magnetic bearings (AMB) are well-known components for the suspension of mechanical objects. The hybrid thrust magnetic bearing (HTMB) with permanent magnet creating bias flux and subsidiary air gap in this paper is used to save energy, and two opposing electromagnetic poles allow control forces in two directions and take account of linearizing effects. The flux distribution is affected by the control voltage and the permanent magnets for the HTMB. Accurate analysis and efficient optimal design are essential to avoid costly trials. The dynamic performances of the HTMB with subsidiary air gap are analyzed. The flux distribution at different time in the HTMB is shown, and the time variation of the magnetic force, the displacement of the thrust plane, the speed of the thrust plane are given respectively in case the voltages are 15V, 20V, and 28V. The inductance of the thrust magnetic bearing is calculated for each position. The described method can simulate the dynamic behavior of the AMB with permanent magnets. It enables design optimization of sophisticated AMBs by extensive parameter studies.