Influence of Manufacturing Tolerances on Cogging Torque in Interior Permanent Magnet Machines with Eccentric and Sinusoidal Rotor Contours.

Rotor shaping methods are frequently used to reduce the cogging torque in interior permanent magnet (IPM) machines. This paper investigates the influence of manufacturing tolerances on cogging torque in IPM machines with eccentric and sinusoidal rotor contours. First, two 12-slot/8-pole IPM machine models are established and the fundamental performance under ideal conditions is presented. Then, based on the most sensitive distributions of nonideal PMs and assembly tooth-bulges, additional cogging torque components are calculated, respectively, together with a comparative study to identify the different sensitivities between the two rotor contour designs. For verification, the field spatial harmonics with and without considering the tolerances are further analyzed, followed by tests on the prototypes with and without amplified tolerances. [ABSTRACT FROM AUTHOR]