Analysis of Electromagnetic Force Waves of Solid Cylindrical Permanent Magnet Synchronous Motors

Solid cylindrical permanent magnet synchronous motors (SCPMSMs) are taken as the study objects in this paper. Based on the magnetic circuit analysis theory, the analytical expressions of radial electromagnetic force waves are deduced. The electromagnetic forces of the motor under both no-load and load conditions are analyzed. The radial electromagnetic force wave sources, amplitudes, time frequencies and spatial orders and the force components which have great influence on motor electromagnetic vibration and noise under two conditions are summarized. The finite element simulation analyses on radial electromagnetic force waves of a high speed SCPMSM under both no-load and load conditions are carried out and so the correctness of theoretical analysis is verified. The results show that for the SCPMSM under both no-load and load conditions, all the radial electromagnetic force frequencies are twice that of the power, that the spatial orders of the primary electromagnetic forces are 2 and that the electromagnetic vibration of stator caused by the second spatial order radial electromagnetic force wave is the main component of the motor electromagnetic vibration and the main source of the motor electromagnetic noise.