Design and Analysis of a Novel Axial Variable-Flux Reluctance Machine with DC-Excited Field and Modular Double Rotor

This paper presents a novel axial variable-flux reluctance machine with modular double rotors (AVFRM-MDR) and DC-Excited Field. This topology does not employ permanent magnets and offers a low-cost alternative to in-wheel electric traction. The proposed topology also has modular rotors to facilitate the fabrication, an axial variable air gap, and a yokeless core made of high grain-oriented (HGO) laminated steel. The characteristics of the AVFRM-MDR include a wide range of flux-weakening capabilities, reduced magnetic losses, and minimal torque ripple, making it suitable for in-wheel applications. An experimental prototype was built to validate the proposed topology. The design considers a 12-slot 10-pole number machine that is evaluated using analytical and semi-analytical models, and 3D finite element analysis. The analytical, numerical, and experimental analysis in this paper shows that inductance profiles, static torque, and back-EMF have a good agreement, proving the effectiveness of the models developed for this topology.