Novel Design of Interior Permanent-Magnet Synchronous Motor Adopting Ferrite Shells on the Rotor Surface
This paper deals with a novel design method for low torque ripple and voltage ripple of interior permanent-magnet synchronous motors (IPMSMs) by using ferrite shells on the rotor surface. The IPMSM with ferrite shells is optimally designed with two design variables related to the structure of the ferrite shells by using the response surface method and the finite-element method in order to minimize torque ripple and voltage ripple. In the vicinity of air gap of the IPMSM, the magnetic flux remarkably fluctuates due to flux-weakening control by the vector inverter. Ferrite shells on the rotor surface can decrease the fluctuation of the magnetic flux effectively. For this reason, the proposed method is a good solution for the robust control of IPMSMs.