A novel disc machine with axial biased flux and complementary salient rotors

Abstract

Disc machines are promising candidates for direct drive in-wheel machines due to the inherent merits such as short axial dimension, high torque density and high efficiency. Currently, most of disc machines have the permanent magnets (PMs) employed on rotor, which can contribute to improved torque but also results in many undesired limitations. Definitely, these structures have large space to install PMs, suitable for pursuing higher torque density. However, with PMs on the rotor also cases some disadvantages. Firstly, the rotors with PMs on have more risk of been damaged since the rotary wheels usually experience the bumps and vibrations. Secondly, PMs would cause the axial force even with bilateral rotors, which may accelerate the aging process of the bearings.