Design and Analysis of a Bearingless Motor with Passive Axial Suspension Through Null-Flux Coils

This paper describes a bearingless motor with passive axial stabilization. Null-flux figure-8 coils are employed to generate passive restorative forces in the axial direction. Using Finite Element Analysis, passive suspension performance is compared between two proposed models, one with iron core structure and another one with a coreless stator. Analytical results show that the coreless model is more suited for the first prototype machine. This is part of a project that aims to achieve full passive suspension in a bearingless motor.