Analysis of Magnetic Bearing Magnetic Field Based on Subdomain Model

Abstract

Precise electromagnetic field analysis is essential for optimizing the performance of magnetic bearings in high-speed rotating machinery. To overcome the computational inefficiencies associated with Finite Element Analysis (FEA), this paper proposes an exact analytical technique based on the subdomain model for radial magnetic bearings. The magnetic domain is partitioned into stator slot and air gap subregions, where Poisson’s and Laplace’s equations are solved, respectively, under the assumption of infinite permeability of the iron core. By satisfying the continuity conditions of magnetic vector potential and magnetic field intensity at the subregion interfaces, the general solutions for the magnetic field distribution are derived. Additionally, the model accounts for the influence of rotor eccentricity on the air gap flux density. The proposed analytical method is validated through comparison with FEA simulations under various operating conditions, including different bias currents and eccentricity angles. The results demonstrate that the subdomain model achieves high accuracy in predicting flux density while significantly reducing computational time, confirming its viability for the efficient design of active magnetic bearing systems.