ABSTRACT
The motor loss consists mainly of copper loss and iron loss. Copper loss indicates the Joule loss of the stator coil, whereas iron loss refers to the core losses. Since there is no secondary winding in the PMSM, the copper loss of a PMSM is lower than that of the corresponding IM. For this reason, PMSMs generally have higher efficiency than IMs. The iron loss takes place in a magnetic material that works in the alternating field. It is generally separated into hysteresis and eddy current losses. The former comes from the hysteresis band of the core, while the latter is caused by magnetic induction. The hysteresis loss is higher than the eddy current loss below the base frequency. The eddy current loss, however, becomes comparable in the high frequency range. In this chapter, basics of magnetism are discussed and the loss models are developed from the perspective of electromagnetics.
