Influence of Flux Barriers and Permanent Magnet Arrangements on Performance of High-Speed Flux-Intensifying IPM Motor

This article investigates the effects of multiple flux barriers (FBs) and permanent magnet (PM) arrangements of flux intensifying (FI) interior PM (FI-IPM) motors at high-speed operation for spindle applications. Common FI-IPM motors possess a low constant power speed range (CPSR), thus limiting their applications. In this article, three multiple-flux-barrier FI-IPM (MFI-IPM) motors with different PM arrangements are studied. First, the air gap flux density, inductance characteristics, and torque component distribution are investigated with various rotor topologies. Then, the performance of the MFI-IPM motors in terms of CPSR and torque ripple is investigated and compared with an original V-shape FI-IPM motor. The analysis reveals that proper rotor designs can significantly improve the performance and CPRS of the MFI-IPM motor. Furthermore, considering the rotor mechanical strength of the MFI-IPM motor at high speeds, magnetic bridges and ribs are added, which thus increases flux leakage and slightly reduces motor performance. Finally, a rated power of 9 kW MFI-IPM motor prototype is fabricated and tested. The experiment results validate the analyses.