Application of an Amorphous Core to an Ultra-High-Speed Sleeve-Free Interior Permanent-Magnet Rotor

The low core losses and high yield strength of amorphous materials are attractive properties for ultra-high-speed rotor applications. This paper proposes an innovative interior permanent-magnet synchronous rotor for ultra-high-speed motors, which takes full advantage of those properties and eliminates the need for sleeves. In order to study the feasibility of the proposed rotor, the electromagnetic properties of the amorphous core are first measured and the challenges for producing such rotors are subsequently discussed. Then, by using numerical methods, the electromagnetic, mechanical, and thermal performances of an example motor with an amorphous rotor core are evaluated and compared to those of a motor with a silicon steel rotor core. Through experimental characterization of the material and multiphysics numerical modeling of an example motor, it is shown that the amorphous material has great potential for producing high power density ultra-high-speed motors.