Axial Active-Passive Suspension Electromagnetic System in Radial Air Gap for Maglev Pump

This paper presents a new type of axial active-passive suspension electromagnetic system for the maglev pump. In industrial applications, the variable residual axial hydraulic force on the impeller may lead to collision and vibration, which need to be compensated. In this paper, a new-type electromagnetic system is constructed with the advantage of providing both active and passive axial force. The designed active magnetic support can generate axial force on diameter magnetized rotor in both positive and negative directions, but it only occupies a small space in the radial air gap. The generated active axial force is proved that it will not change with the rotation angle of the rotor by theoretical derivation. Besides, its control algorithm is also proposed. We designed, simulated and built a prototype, and tested it through the control experiment. And the active force is almost unaffected in the test during rotation and speed step. The prototype system achieves maximum controllable axial force of \pm2.0N (0.67N/A), which effectively enhances the axial stiffness. The damping factor of active suspension is 70 times higher than that of passive suspension, which can successfully suppress axial vibration.