LAUSR

In order to make more effective use of space in the electric machine, a novel field modulated permanent magnet gear (FMPMG) machine is proposed. The key design aspect of the proposed FMPMG machine is adopting an inner rotor configuration and a specially designed stator core, with fixed modulator pieces, to improve the fabrication feasibility and rotation reliability. Harmonic analysis with detailed theoretical derivation is performed and reveals that the modulator pieces fixed to the stator can modulate the flux density distribution as well and realise a magnetic-gearing effect. The major parameters are designed and modelled by the 2D finite element method (FEM). First, based on the simulation analyses of the radial flux density distribution in the ‘pseudo’ outer and inner air gap, the specially designed stator is verified to create a nested magnetic-gearing effect together with the rotor PMs. The back electromagnetic force and electromagnetic torque waveform are further analysed, and the results indicate that the proposed FMPMG machine is more suitable for use as a sinusoidal excitation drive. Finally, a prototype is fabricated for experimentation to further verify the theoretical and FEM simulative validity of the proposed FMPMG machine.