Analysis of PM machines with sectored-stator

This paper focuses on a new structure of permanent magnet machines suitable for highly integrated in-wheel motors for vehicle application. In particular, the main feature of the integrated solution lays in the removal of a sector of the stator in order to have the required space for the brake caliper. However, the sectored-stator introduces an additional anisotropy in the electromagnetic circuit affecting the overall torque ripple of the machine. As a consequence, a general FEM-based analysis of sectored-stator PM machines has been undertaken to evaluate the important behaviors, such as output torque, cogging torque, torque ripple, back electromotive force, and unbalanced magnetic force. Furthermore, the effect of a considered winding arrangement has been evaluated using the winding function theory, obtaining interesting results related to the magneto-motive force distributions when a missing sector is present.