Design and Comparative Study of Ultrahigh-Speed Permanent Magnet Motors With Different Soft Magnetic Materials

Abstract

The ultrahigh-speed (UHS) electrical motor is an essential component for air compressors of hydrogen fuel cells and has been attracting more and more interest in the last decades. For UHS motor design, topology and material are two critical factors. This article presents the design and comparison of four 25 kW 100 000 r/min permanent magnet motors (PMMs) with two different topologies, namely six stator slots and two rotor poles (6S2P) and 12 stator slots and four rotor poles (12S4P), and two different stator core materials, namely high silicon sheet steel (10JNEX900) and amorphous magnetic alloy (ZOM-6). The magnetic material properties are measured at different frequencies using the ring sample and single sheet testers for accurate performance analysis. A comprehensive comparative study shows that the 12S4P UHS motor with an amorphous alloy stator core has the highest efficiency. The torque ripple of the 12S4P motor is much lower than that of the 6S2P motor. The radial electromagnetic force (REF), vibration, and noise analyses reveal that the motors with amorphous magnetic alloy stator cores generate lower noise than those of high silicon sheet steels.