Design synthesis of hybrid stator type flux-switching bearingless permanent magnet memory machines

Abstract

A magnetic flux-switching type bearingless permanent magnet memory motor is proposed, which not only solves the problem of friction in high-speed rotating mechanical bearings, but also achieves the true effect of “variable flux” operation with almost no excitation loss through permanent magnets with low coercivity such as aluminum nickel cobalt that can be adjusted online by applying only instantaneous pulse current. Ultimately, the goal of efficient magnetic flux regulation, high torque density, and high stable suspension force can be achieved. A hybrid stator type flux-switching bearingless permanent magnet memory motor (HSTFBPMM) is a special type of motor that combines magnetic levitation technology, a flux-switching permanent magnet motor, and the adjustable magnetic flux principle. It integrates the advantages of the former without mechanical wear and lubrication, and the latter with simple structure, high power density, and adjustable air gap magnetic field. This article first provides a detailed introduction to the structural characteristics of an HSTFBPMM. Secondly, based on the principles of torque generation, suspension, and magnetic flux regulation, the magnetic field distribution, no-load permanent magnet flux, back electromotive force, inductance, positioning torque, and static torque were analyzed in detail. The results lay the foundation for establishing an accurate mathematical model for an HSTFBPMM incorporating the aforementioned physical quantities in the future.