Improving the Torque Ripple with an Axial and Solid Double-Inner-Rotor Configuration in PM Flux Switching Generators

A solid-double-rotor with a 3D magnetic circuit geometry is proposed for a flux-switching generator with PMs only in the stator. Despite its high power density characteristic, this machine "suffers" from non-negligible torque ripple. Vibrations and noise are thus its nightmares! To attenuate these effects, we propose a novel solid-double-rotor geometry where the electromagnetic force distribution through each rotor layer cancels each other out, ideally. Simulation tests were accomplished using a hybrid 3D FEM-multiphysics/electric-circuit model for the generator and its load. It rotates at 3000 rpm and supplies 68.8 kW to an AC/AC power converter connected to a simplified version of Boeing 767 electrical load. Results are encouraging, achieving about -60% in torque ripple at no load, and over -95% for the rated operating case.