2022 Volume 46 Issue 1 Pages 16-21
Magnetic-geared motors (MGMs) have attracted attention since their torque density is superior to conventional electric motors. Among the types of MGMs, an interior permanent magnet (IPM) type has a feature of high efficiency because the IPM-type can reduce the eddy current loss in magnets. On the other hand, in the IPM-type MGM, the PM motor part and the MG part magnetically interact with each other, which is called the magnetic interaction. In a previous paper, the influence of the magnetic interaction on the output torque was investigated. However, the influence on the power factor and the efficiency has not been clarified yet. This paper studies the influence of the magnetic interaction on the power factor and the efficiency of the IPM-type MGM. The influence of the magnetic interaction on the power factor is discussed by deriving a voltage equation of IPM-type MGM. Moreover, the power factor and the efficiency are calculated and measured to clarify a suitable current phase from the viewpoint of a high-power-factor and high-efficiency drive.