Control of rotor radial displacement for bearingless induction motors

It is the focus of the research on the bearingless motors to suspend the rotor stably by controlling rotor radial displacement. Without studying the relationship between the radial suspension force and rotor radial displacement, traditional control method for rotor radial displacement has some drawbacks such as the complexity of computation and the time-consuming tuning. In order to overcome these drawbacks, a new approach to control the rotor radial displacement was proposed based on the relationship between the rotor radial displacement and radial suspension force. The airgap flux orientation is adopted to decouple the electromagnetic torque and radial suspension force. This approach directly controls the rotor radial displacement of bearingless induction motors. In addition, a control system was designed by applying this approach. The simulation results show that the proposed control strategy is effective in improving the static and dynamic performance of stable suspension of bearingless motors. In addition, the proposed approach realizes direct control for rotor radial displacement of the bearingless induction motor.