Comparative Study of Transverse-Dislocated Magnetic-Field Modulated Brushless Contra-Rotating Machine With Different Rotor Structures

The transverse-dislocated magnetic-field modulated brushless contra-rotating machine (TDMFM-BCRM), composed of stator, transverse-dislocated modulation (TDM) rotor, and permanent-magnet (PM) rotor, is a novel contra-rotating machine (CRM) for contra-rotating propulsion system (CRPS). Compared with conventional CRMs, the TDMFM-BCRM is the only one that has the following advantages at the same time: no rotating winding, no brushes and slip rings, and equal-opposite torque at any time. In this article, the air-gap magnetic-field modulated behaviors of the proposed TDMFM-BCRMs with different PM rotor structures including surface-mounted PM rotor, consequent-pole PM rotor and spoke-type PM rotor, and different TDM rotor structures with multi-unit topologies are comparatively investigated by the analytical analysis. Then, the key parameters in the TDMFM-BCRMs with different rotor structures those influence the air-gap magnetic-field modulated effect are studied by the theoretical and simulated analysis. The electromagnetic performances of the TDMFM-BCRMs with different rotor structures are compared. The comparison results show that the spoke-type TDMFM-BCRM with 1-4-5-3 has the best comprehensive performance. Finally, the theoretical analysis are verified by one TDMFM-BCRM prototype with spoke-type PM rotor and 1-4-5-3.