Research ArticleSuspension force control of bearingless permanent magnet slice motor based on flux linkage identification

•A suspension force control strategy for bearingless permanent magnet slice motor.•It improves the control accuracy and dynamic performance of suspension force.•It realizes the decoupling control of electromagnetic torque and suspension force.•The control system based on the control strategy has fine anti-disturbance.•It has versatility and can provide a reference for other bearingless motors.

The control accuracy and dynamic performance of suspension force are confined in the traditional bearingless permanent magnet slice motor (BPMSM) control strategies because the suspension force control is indirectly achieved by adopting a closed loop of displacement only. Besides, the phase information in suspension force control relies on accurate measurement of rotor position, making the control system more complex. In this paper, a new suspension force control strategy with displacement and radial suspension force double closed loops is proposed, the flux linkage of motor windings is identified based on voltage-current model and the flexibility of motor control can be improved greatly. Simulation and experimental results show that the proposed suspension force control strategy is effective to realize the stable operation of the BPMSM.