Electromagnetic Performance Analysis on the Bearingless Permanent Magnet Synchronous Motor With Halbach Magnetized Rotor

In order to approximately obtain sinusoidal air-gap magnetic field and get larger radial levitation force of the bearingless permanent magnet synchronous motor (BPMSM), a novel BPMSM with Halbach magnetized rotor is proposed. Firstly, the suspension and rotation mechanisms of the BPMSM are introduced. The control mechanism of producing the radial levitation force in single direction and arbitrary direction is analyzed in detail. The mathematical models of the radial suspension force are given. Secondly, the comparative research on the BPMSMs with the Halbach magnetized rotor and parallel magnetized rotor is carried out. The air-gap magnetic field, back electromotive force (EMF), radial suspension force, and torque are calculated and compared. Finally, the prototype motor equipped with the Halbach magnetized rotor is constructed. Some experimental results are tested and the stable suspension operation of the proposed motor is realized.