Aiming at rotor speed identification of bearingless induction motor, a novel speed-sensorless vector control scheme of bearingless induction motor based on reactive power model reference adaptive system (MRAS) of torque winding was proposed. Using the instantaneous reactive power calculated from back-electromotive force multiplied by the stator current as the adjustable model, and establishing the relationships between the speed and the reactive power of torque windings, the presented method eliminated the integration process and the effect of stator resistance in traditional MRAS method, and then realized the on-line rotor speed identification.Simulation results showed that the rotor speed of bearingless induction motor can be precisely inspected in low and high speed operation with load disturbances and the stable sensorless suspension operation can be achieved with good dynamic and static performance by using the proposed method.
