Principle and implementation of radial disturbance feedforward compensation control for bearingless permanent magnet slice motors

In this paper a bearingless permanent magnet slice motor (BPMSM) is investigated and its levitation principle and mathematical model of levitation force are analyzed and deduced respectively. A extended state observer (ESO) of levitation system is established for observation of outer disturbance imposing on levitation system. Then, the observed disturbance is utilized to form compound control with the radial displacement PID by feedforward compensation. Finally, simulation and experiment results show the effectiveness of the proposed control strategy.