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This paper provides a detailed finding of the mechanics of vibration in permanent magnet (PM) synchronous motors due to electromagnetic (EM) origins. Several fractional-slot PM topologies are investigated to quantify the vibration phenomenon that is influenced by motor slot/pole and winding configurations. This paper also sorts out the vibration mode order that is responsible for deformation and the resulting excitation frequency. A finite-element-based cosimulation in the EM and structural domain is used to find the radial forces and, hence, the displacement, to quantify the vibration/noise performance of these selected motors. The displacement and frequency are converted to the sound pressure level to show the relative differences in the noise levels among these motor topologies. The selected motors were experimentally tested to verify the theoretical findings. [ABSTRACT FROM AUTHOR]

Cogging torque minimization is necessary for low torque ripple applications such as precision tooling, robotics, etc. Various techniques are available but few techniques are proved to be effective in mass production under manufacturing tolerances/variations. The research provides a design approach to minimize cogging torque by making the motor robust to manufacturing variations and dimensional tolerances. Several control and noise factors are identified to apply the robust design technique. The quality of robustness is judged by the signal-to-noise ratio. A tradeoff is exercised to maximize output torque in selecting the control parameters. The research shows the effectiveness of such design techniques in designing motors for mass production without adding cost or complexity. Experimentation by modeling has been chosen using finite element analysis. Motors using the optimized parameters are built and tested thus verifying the design approach. [ABSTRACT FROM AUTHOR]

This paper analyzes the noise and vibration in permanent-magnet synchronous motors (PMSMs). Electromagnetic forces have been identified as the main cause of noise and vibration in these machines, rather than the torque ripple and cogging torque. A procedure for calculating the magnetic forces on the stator teeth based on the 2-D finite-element (FE) method is presented first. An analytical model is then developed to predict the radial displacement along the stator teeth. The displacement calculations from the analytical model are validated with structural finite-element analysis (FEA) and experimental data. Finally, the radial displacement is converted into sound power level. Four different PMSM topologies, suitable for the electric power steering application, are compared for their performances with regard to noise and vibration. [ABSTRACT FROM PUBLISHER]

This paper examines the torque ripple and cogging torque variation in surface-mounted permanent-magnet synchronous motors (PMSMs) with skewed rotor. The effect of slot/pole combinations and magnet shapes on the magnitude and harmonic content of torque waveforms in a PMSM drive has been studied. Finite element analysis and experimental results show that the skewing with steps does not necessarily reduce the torque ripple but may cause it to increase for certain magnet designs and configurations. The electromagnetic torque waveforms, including cogging torque, have been analyzed for four different PMSM configurations having the same envelop dimensions and output requirements. [ABSTRACT FROM AUTHOR]