Direct control of bearingless permanent magnet synchronous motor based on prediction model

—The direct control for the bearingless permanent magnet synchronous motor (BPMSM) has problems of large ripples of flux linkage, torque, and suspension force due to sampling time delay. To solve above problems, a predictive direct control method is proposed based on the traditional direct control by adding prediction model. Firstly, the generation principle of radial suspension forces of the BPMSM is introduced. Secondly, the models of the predictive direct control method are given based on the traditional direct control, and the time-delay compensation model is deduced. Thirdly, the predictive direct control system is constructed, and the simulations are carried out. Finally, the proposed control strategy is applied to a prototype, and the related experimental results are given and analyzed. The results of the simulations and experiments show that compared with the traditional direct control of the BPMSM, the predictive direct control strategy can effectively reduce the ripples of flux linkage, torque, and suspension forces, and improve the static and dynamic performance of the BPMSM. © 2021, Electromagnetics Academy. All rights reserved.