Synchronous reluctance and interior permanent magnet motors

This paper focuses on the key notions about analysis and design of synchronous reluctance and an interior permanent magnet motors. The aim is to highlight not only the advantages of such machines but also some drawbacks of theirs, such as the low power factor and the torque ripple. The strategies to reduce such a drawbacks are also reported. Machines adopting Ferrite magnets instead of rare-earth permanent magnet are considered. It is shown that the reduction of the performance is quite limited thanks to the anisotropic structure, compensating the use of low energy PMs by means of the reluctance torque component. At last, fractional-slot winding concepts are summarized, highlighting some tricks to overcome the high torque ripple in such a machines.