Unbalanced vibration control strategy of bearingless induction motor based on inverse system decoupling

Abstract

Bearingless induction motor is a multi variable, nonlinear and strong coupling object, in order to achieve its sus- pension control with high performance, the dynamic model of magnetic suspension system is established; and the radial dis- placement of bearingless rotor is separated into two parts, include random displacement component and unbalanced vibration displacement component. Then by inverse system method, dynamic decoupling control between the two random displacement components is achieved. On this basis, through the compensation controller of unbalanced vibration, the compensation force of unbalanced vibration is regulated and estimated real time, and the control current of unbalanced vibration compensation force is calculated. The compensation force is used to counteract the unbalanced exciting force of bearingless rotor. Under the dq coordinate system oriented by the rotor flux-linkage of torque system, the control current compensation of unbalanced vibra- tion is achieved. At the end, simulation verification and analysis are made. From the simulation results, it is clear that when the proposed control strategy is adopted, the unbalanced vibration of bearingless rotor can be inhibited effectively in the start stage; the unbalanced vibration displacement can be eliminated in steady state. The proposed control strategy is effective and feasible.