Research on electromagnetic performance of an axial magnetic-field-modulated brushless double-rotor machine for hybrid electric vehicles

This paper proposes an axial magnetic-field-modulated brushless double-rotor machine (MFM-BDRM), which is suitable for application in hybrid electric vehicles (HEVs). As the axial MFM-BDRM has dual mechanical ports, two connection ways of the machine in HEV system are evaluated, and the better connection way is selected based on power comparison. Speed decoupling characteristic and operation modes of the axial MFM-BDRM as generator, magnetic gear and motor are discussed. Electromagnetic performance of three operation modes, viz. the waveforms of no-load back electromotive force (EMF), torque transmission capability, torque ripple and power factor, is investigated. The above analyses are simulated with three-dimensional (3-D) finite-element method (FEM).