A Novel Speed-Sensorless Suspension Decoupling Control Strategy for Bearingless Motor Based on Linear Extended State Observer

In this paper, a novel speed-sensorless suspension decoupling control strategy for bearingless motor was proposed based on linear Extended State Observer (ESO). In the proposed control strategy, a second-order and a third-order linear-ESO algorithm were added respectively into torque d-q axis current-loop and suspension system x-y direction displacement-loop. A product of electrical angular speed and torque system d-q axis current and a product of torque q axis flux and suspension system d-q axis current were defined as disturbances in order to use the linear-ESO algorithm to estimate the defined disturbances. By obtaining speed information and compensation for disturbance force, the motor can work on speed-sensorless condition and traditional decoupling algorithm can be simplified. The simulation results show that the proposed control strategy can realize accurate speed estimation and guarantee stable suspension under the rated speed.