| 摘要 |
A brushless electrical machine for converting between electrical and mechanical energy includes a rotor supported on bearings for rotation about an axis of rotation, and a stator that is stationary and magnetically acts upon the rotor. The rotor includes two ferromagnetic rotor portions separated by a magnetic insulator, forming an axial armature air gap between the ferromagnetic rotor portions. At least one of the two ferromagnetic rotor portions has multiple axial extending protrusions facing the axial armature air gap around a circumference. An air core armature having multiple phase windings is located in the axial armature air gap. A ferromagnetic yoke and homopolar flux generator are mounted to the stator. The homopolar flux generator generates homopolar flux in the protrusions of the rotor and the ferromagnetic yoke forms two rotor-to-stator air gaps with the rotor. Each ferromagnetic rotor portion and the rotor-to-stator air gaps provide sufficient distance between the axial armature air gap and the surfaces of the ferromagnetic yoke at the rotor-to-stator air gap such that the circumferential magnetic flux distribution in the ferromagnetic yoke at the surface of the rotor-to-stator air gap is substantially uniform.In operation, homopolar flux generated in the homopolar flux generator mounted to the stator is passed from the stator to the rotor, and across the axial armature air gap between the two spaced ferromagnetic rotor portions of the rotor, while minimizing any short-circuiting of the flux between the rotor portions with the magnetic insulator. The flux across the axial armature air gap is focused into multiple, axially projecting rays of flux through the multiple axial extending protrusions facing the axial armature air gap, producing flux variations through the armature in the armature airgap. Electrical power is provided to, or extracted from, the air core armature windings, depending on whether the machine is used for motoring or generating power.
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