Maximum Transmission Torque Improvement of Interior Permanent Magnet Magnetic-Geared Motor

Abstract

　An interior permanent magnet magnetic-geared motor (IPMMGM) is proposed in order to decrease the amount of permanent magnets. The assemblability of the IPMMGM is high compared with a conventional surface permanent magnet magnetic-geared motor. However, the maximum transmission torque of the IPMMGM decreases. In this paper, the shape of the stator tooth and pole piece of the low-speed rotor is focused to increase the maximum transmission torque of the IPMMGM. Firstly, the harmonic magnetic flux generating transmission torque is investigated by the Maxwell stress tensor. Secondly, the influence of the harmonic magnetic flux on transmission torque is mathematically described. Finally, the torque due to the harmonic magnetic flux of 4 models is compared.