Abstract: Based on a same model of the radial magnetic bearing, the integral computation is compared with linear approximate computation and the finite element method. The results indicate that integral computational method is feasible, especially when the gap is very small relatively, the relative error of gap reluctance produced in integral method is obviously smaller than that produced in the linear approximate calculation. In addition, the precision of linear approximate calculation is discussed from two aspects of absolute error and relative error, and the formula with three-order algebra precision is put forward. Not only precision of equivalent magnetic circuit can be improved by integral computation of gap reluctance, but also a differential method can be provided for analyzing magnetic suspension system.

Key words: Active magnetic bearing (AMB), Finite element method, Flux, Gap reluctance