Dual-sub-region rotor design of a permanent magnet hub motor with enhanced speed regulation and output torque for electric vehicles

To broaden the speed regulation range and enhance the capability of output torque, a dual-subregion rotor design of the permanent magnet hub motor is newly proposed. By employing dual-subregion design, the rotor is tactfully designed into two regions, named near-permanent-magnet (near-PM) region and near-airgap (near-AG) region, respectively. In the near-PM region, the method of magnetic flux regulation is applied to weaken the excitation magnetic field and broaden the speed range. While, in the design of the near-AG region, to enhance the low-speed high-torque capability, the concept of editing-airgap is introduced to improve the distribution of the airgap harmonics. Then, a dual-subregion rotor permanent magnet hub motor is designed, analyzed and tested. The performances verify that the proposed DSR-PM hub motor possesses a wide speed range and low-speed high-torque output capability.