Influence of skewed and segmented magnet rotor on IPM machine performance and ripple torque for electric traction

The paper presents impacts of the stator slot with skew and segment magnet rotor on the performance of interior permanent magnet (IPM) machine for an electric traction. Comparisons of the average torque, torque ripples, cogging torque and no-load back EMF with skew and un-skew are given and how suitable a segmented rotor IPM machine and its torque characteristic and the field weakening capability are investigated. The results of the machine performance comparisons are based on comprehensive use of finite element analysis tools (Ansoft Maxwell 2D).One of the machine designs with one stator slot-pitch skew and no-segment magnet rotor for electric traction has been manufactured as prototype. From the FEA results, it shows that the IPM synchronous machine with two-teeth stator slots skewed and two-segmented magnet rotor has better performance than the conventional IPM synchronous machine.