The work by Dr. Chunhua Liu

Dr. Chunhua Liu proposes a new electric magnetic-geared (EMG) machine, which artfully incorporates the magnetic gear into an outer-rotor inserted permanent-magnet machine. This new machine can be targeted for electric unmanned aerial vehicle (e-UAV) application. The key is to artfully share the sandwiched-rotor for both the PM machine and the magnetic gear. As a result, the proposed machine can operate with high power for propelling the e-UAV.

Link: http://ieeexplore.ieee.org/abstract/document/7932499/