Design and Analysis of Flux-Intensifying Spoke-type IPM Motor for Improving Output Torque and Flux-Weakening Performance

This work presents a flux-intensifying spoke-type IPM (FI-SIPM) motor to enhance the operational flux density of permanent magnet (PM), output torque, and flux-weakening performance for a wide-speed range. By combining the asymmetric magnetic flux barriers and segmented PM in the rotor core, the flux-intensifying effect is realized by changing the characteristics of inductances (L-d > L-q). In the paper, the rotor design concept of the proposed FI-SIPM is firstly presented. Next, the influences of magnetic flux barriers and segmented PM on torque, PM operating flux density, and irreversible demagnetization are investigated. Then, the operational characteristics of the proposed and common Spoke-type IPM motors in the wide-speed range are compared. The study results prove that the proposed motor can improve its performance with higher output torque, lower torque ripple, better flux-weakening ability, and a wider constant power speed range (CPSR). In addition, the demagnetization risk is also improved compared with the conventional spoke-type IPM motor. Finally, the analyses are validated by finite element analysis (FEA).