Design, analysis and control of a new repulsive-type magnetic bearing system

A repulsive-type magnetic bearing system in which the radial bearing sectio n makes good utilisation of the repulsive forces between the stator and the rotor permanent magnets results in a simplified axial control scheme. The authors report the design, analysis, fabrication and implementation of a ne w repulsive-type magnetic bearing system for a horizontal-shaft machine. Th e shape and configuration of the permanent magnet is the most critical comp onent for satisfactory operation of this type of magnetic bearing. Modellin g of the permanent magnets is done with the help of finite-element analysis and the nature of the repulsive forces and the stiffnesses are estimated a long the three directions. Using the forces and expressing the rotor dynami cs, the modelling of a real physical repulsive-type magnetic bearing system is discussed. The controller is configured around a digital signal process or. A prototype model has been designed and fabricated and experimental res ults are presented.