A Novel Magnetic-Geared Machine With Dual Flux Modulators

A novel dual-flux-modulator magnetic-geared (DFM-MG) machine with high torque capability and high PM use efficiency is proposed. The stator of the proposed DFM-MG machine could not only be used to accommodate the armature winding, but also has the ability to enhance the magnetic gearing effect as an additional flux modulator. In the proposed DFM-MG machine, the low-speed rotor (LSR) with spoke-array permanent magnets (PMs) is sandwiched between the stator and flux modulator. This design will bring the benefits of significant reduction of magnetic flux leakage between adjacent PMs on the LSR, and large enhancement of the useful magnetic field harmonics. Moreover, the location of the stator enable it to be part of the magnetic circuit of the magnetic flux excited by either high-speed rotor (HSR) PM or LSR PM, so that the armature winding could be coupled with all of the PM in the proposed machine to achieve the electromechanical energy conversion. The operating principle and electromagnetic performance of the proposed DFMMG machine are investigated by dividing it into one vernier PM machine, one PM brushless machine and one magnetic gear. Finally, the predicted performance of the proposed DFM-MGM is validated by the measurements on a proof-of-concept prototype machine.