Characterization of a Variable Flux Machine with Mechanical Flux Modulators above the Rotor Poles

This work introduces a permanent magnet synchronous machine (PMSM) rotor topology that passively adjusts the rotor flux linkage to improve machine performance in the high-speed region. Movable core elements, referred to as flux modulators, are used above each motor pole. These modulators are only controlled by the machine’s rotational speed. Above a certain speed, the flux linkage is mechanically reduced as the modulators move outward due to centrifugal forces. The proposed machine is compared to a conventional internal permanent magnet (IPM) machine in terms of efficiency. The forces acting on the modulators during operation are evaluated, and a mechanical stress simulation is performed on the proposed machine. Finally, an alternative geometry of the VFM is shown, which increases the total flux reduction capability.