A Novel Flux Focusing Magnetically Geared Machine with Reduced Eddy Current Loss

Abstract

This paper proposes a novel flux focusing magnetically geared (MG) machine for wind power generation, considering the permanent magnets (PMs) eddy current loss and the balance between the pull-out torque of MG machine and the back-electromotive force (EMF)of the PM brushless machine. The PM eddy current loss in the two rotors of the conventional surface-mounted MG machine is calculated and analyzed by using finite-element method. By adopting serial-spoke structure in the inner rotor, a novel rotor structure for a MG machine is proposed to reduce the PM eddy current loss. Moreover, in order to balance the pull-out torque and the back-EMF, several serial-spoke structures and the main design parameters are investigated. Then, a quantitative comparison between the proposed topology and the conventional surface-mounted MG machine is performed. The analysis results indicate that the PM eddy current loss of the proposed MG machine can be significantly reduced and its pull-out torque and back-EMF can be balanced well.

Investigating the Performance of a Fully Laminated Flux-Focusing Magnetic Gearbox

“…However, an experimental prototype was not presented. Liu et al used an interesting slotted laminated structure to maintain individual lamination stacks in place in a magnetically geared generator [18]. Most cage rotor designs provide axial bearing support on both sides of the stack length.…”

A Novel Dual-Permanent-Magnet-Excited Machine with Flux Strengthening Effect for Low-Speed Large-Torque Applications

“…Integrated magnetic-geared machines (IMGMs) and PM vernier machines are the most common ones in FMPM machines. However, since there exist multi-layer air-gaps [5][6][7][8][9][10][11], IMGMs suffer from complex mechanical structures, thus resulting in a decrease in practicality. On the contrary, PM vernier machines with simple structures are favored and widely investigated by researchers [12][13][14][15][16][17][18][19][20].…”