Torque Ripple Reduction for Permanent Magnet Motor Using New Configuration for Concentrated Windings

This paper presents a new configuration for the concentrated windings of permanent magnet motors in order to reduce the torque ripple. There are limited choices for the concentrated windings in conventional permanent magnet motors when selecting the numbers of poles and slots, which results in winding factors for harmonics that cannot be zero and the corresponding torque ripple remains. Unlike conventional concentrated-winding motor, whose teeth are all wound with one coil, the proposed concentrated-winding motor has some teeth with multiple coils wound around. The number of turns for each coil can be optimized to reduce its winding factors for harmonics to nearly zero so that the corresponding torque ripple could be significantly reduced. Prototypes of the conventional and proposed motors were constructed, and the experimental results are compared. Simulation and experimental results confirm the torque reduction effect of the proposed concentrated-winding motor.