An integrated magnetic-geared permanent-magnet in-wheel motor drive for electric vehicles

This paper proposes an integrated in-wheel motor for electric vehicles. It can offer the advantages of lightweight, compact size, high efficiency and low-speed high-torque operation. The key is to artfully integrate a coaxial magnetic gear into a permanent-magnet (PM) brushless motor in such a way that they can share a common PM rotor, hence the low-speed requirement for direct driving and the high-speed requirement for compact motor design can be achieved simultaneously. Both the static and dynamic characteristics of the proposed motor have been studied by time-stepping finite element method. A 500 W prototype has also been built up to verify the validity of the proposed motor.