Vibration Reduction of IPMSM with Concentrated Winding by Making Holes

The recent trend of an interior permanent magnet synchronous motor (IPMSM) is shifting from distributed winding to concentrated winding for the purpose of downsizing, high efficiency and natural resources saving. The IPMSM with concentrated winding, however, is noisy because of the stator frame deformation by the radial forces. This paper reports flux barriers preventing flux short circuit arranged in the rotor for the purpose of preventing demagnetized, reducing the torque ripple and the cogging torque also reduce the radial force that causes the acoustic noise and the vibration. The improvements of reducing the radial force and the torque ripple at high torque operation by making some holes inside the rotor are examined. The vibration, efficiency by the experiments and the analytical results are evaluated. It is cleared that the vibration of the IPMSM with holes inside the rotor is reduced without decreasing the efficiency.