Rotor Vibration Control of a Bearingless Induction Motor Based on Unbalanced Force Feed-Forward Compensation and Current Compensation

To handle the unbalanced vibration caused by uneven rotor mass distribution in a bearingless induction motor (BIM), a control strategy that integrates unbalanced feed-forward compensation and current compensation is presented. Firstly, based on the analysis of the BIM rotor vibration mechanism and the unbalanced vibration influence on the performance of the BIM, the dynamic model of the rotor is derived. Secondly, an unbalanced force feed-forward compensation controller is designed to extract the synchronous vibration signals through the synchronous signal detection unit, and then the compensation force components are generated by unbalanced feed-forward compensation controller. In addition, considering the influence of current in the rotor induced by suspension winding, a current compensation link is applied to the system to enhance the suspension performance. Finally, a rotor unbalanced vibration compensation control system of the BIM is established. The simulation and experimental results show that the proposed compensation control strategy not only can effectively reduce the rotor radial displacement and suppress the unbalanced vibration, but also can improve the suspension performance.