Subdomain Method for Permanent Magnet Biased Homo-Polar Radial Magnetic Bearing

This paper presents an analytical model based on the subdomain method and conformal mapping method for predicting the performance of the permanent magnet (PM) biased homo-polar radial magnetic bearing (HRMB). Due to the homo-polar PM flux field of HRMB, the subdomain method combined with the periodic boundary condition is applied to obtain PM flux field distribution. The saddle winding is treated as a current sheet, while the rotor eccentricity is taken into account with a simple relative permeance model. The conformal mapping method is employed to obtain ending field distribution of HRMB. The developed analytical model is validated by 3-D finite element analysis. It is shown that the coupling effect between two radial freedoms is negligible. Ultimately, the parameters of HRMB are analytically optimized, while the predicted result from proposed analytical model is compared with prototype's experiment results.