Multi-Wound Axial Flux Generators with Halbach Array Rotors

This paper presents three coreless axial flux permanent magnet (AFPM) generator topologies that feature magnetically and electrically decoupled outputs using a single prime mover. The proposed topologies include: (1) two separate generators mounted on the same shaft, (2) a nested configuration with a smaller generator inside a larger one, and (3) a multi-wound generator with two sets of windings and different pole numbers for each rotor side. The multi-wound generator is selected for further investigation due to its superior power-to-volume ratio and the advantage of utilizing a single structure for stator cooling. The airgap magnetic flux density equation is derived using the superposition technique to analytically explore the effects of rotor pole number differences. Additionally, three-dimensional finite element analysis (FEA) is employed to investigate the magnetic cross-coupling between different stators.