Research on Air Gap Magnetic Field for Permanent Magnet Toroidal Motor with Rotor Eccentricity

Permanent magnet toroidal motor (PMTM) is a novel type of space motor integrating worm planetary drive with permanent magnet synchronous motor. In this paper, based on boundary subdomain method, the analytical model of magnetic field with static eccentricity is established to study planet static eccentricity of PMTM. The air gap variation with eccentricity is introduced into the model, and the analytical equation of no-load air gap flux density is solved. The analytical magnetic flux density with planet eccentricity is verified by comparing with finite element results. The harmonic analysis of inner air gap flux density with planet eccentricity and planet core loss are carried out. The change of core loss with eccentricity are discussed. The results are of great significance to explore the operation characteristics of PMTM.