Analysis and suppression of vibration characteristics of interior-type fractional-slot direct-drive permanent magnet motors

ObjectiveTo suppress electromagnetic vibration and improve the operational smoothness of an internal fractional-slot direct-drive permanent magnet synchronous motor (PMSM), an electromagnetic vibration suppression scheme based on auxiliary slots in the stator teeth was proposed.MethodsFirstly, a two-dimensional motor model was established, and the electromagnetic force and its harmonic distribution characteristics under different operating conditions were systematically studied using a combined analytical and finite element analysis method. The natural frequencies of the stator structure were obtained through modal analysis, and the validity of the motor model was verified by combining the harmonic frequencies of the electromagnetic force. Subsequently, a magneto-structural coupling model was established to conduct harmonic response analysis, clarifying the influence mechanism of the electromagnetic force and its harmonic components on vibration characteristics. The effectiveness of the simulation model was verified through tests.ResultsThe results show that through the optimization design of auxiliary slots in the stator teeth, the electromagnetic vibration amplitude is reduced by 28.45%, and the torque ripple rate is reduced by 18.11%.