Low Cost Active Magnetic Bearings-Concepts and Examples

The objective of this paper is to present innovative new thrust and radial magnetic bearing designs using permanent magnet bias not previously published. They are expected to be significantly lower in cost than conventional all electromagnetic bearings. The new designs use permanent magnet bias in a way not introduced before. The resulting magnetic bearings are able to use only half of the number of power amplifiers than conventional magnetic bearings, as well as consuming significantly less operating power in the bearing coils. However, the bearings are generally not larger than conventional all electromagnetic bearings. Finally, these new permanent magnet bias bearing designs are generally not longer axially than all electromagnetic bearing designs, unlike other types of permanent magnet bias designs such as homopolar magnetic bearings. This is important from the rotor dynamics point of view. This innovation has the potential to reduce the overall magnetic bearing system hardware volume production cost by 20% to 30% as well as reduce coil current operating costs in the range of 35% to 40%.