Performance Analysis And Optimization Strategy Of Bearingless Induction Motor

Bearingless motors which combine magnetic levitation windings with the drive windings will be used widely in the area of motor-store-energy, aeronautics and astronautics. This paper do some research on the bearingless induction motors ,the mathematical model, the influence of the rotor induced current for the levitation force, the timing performance of the motor windings and the analysis of the bearingless system stability included.Based on the establishment of bearingless induction motor mathematical model, Two different control strategies of levitation subsystem are compared. This is the groundwork of the study.The rotor may induce much current because of the motor windings with two poles and the levitation windings with four poles. This may bring the difference between the excitation current and the stator current in magnitude and phase, which makes the forces in x and y directions coupled. To decouple the forces, the corresponding strategy is adopted based on the inverse system. Simulation and experiment validate that the strategy is correct and feasible.The influence of the timing performance on the levitation performance is analyzed. To utilize the advantages of the rotor flux orientation control and the direct torque control, the rotor flux orientation control system with voltage decoupled is researched. The dynamic and the static performances are validated by simulation and experiment.Base on the classical control theory, the frequency domain mathematical model of the levitation subsystem is modeled, some research on the stability of the levitation system is done, the rule of the control system design is discussed at the end. The research may be a reference for levitation system design.