Practical Application of the Analytical Method of Electromagnetic Circuit Analysis for Determining Magnetic Forces in Active Magnetic Bearings

Abstract

The paper presents an example of the practical application of the previously proposed analytical method for the analysis of electromagnetic circuits of active magnetic bearings to search for force characteristics taking into account control laws. It consists in introducing detailed equivalent circuit substitution schemes and applying the contour flux method. These schemes contain all elements of active magnetic bearings (AMBs), such as air gaps under poles, sections of stator and rotor pressure lines, grooves filled with copper windings, and others. Magnetic resistances of circuit sections included in the expressions are determined by schematizing the magnetic flux paths. Validation of the method, methodology and calculation software is performed for an axial active magnetic bearing. This bearing is a part of a designed and technically implemented rotor laboratory rig in a complete combined passive-active magnetic suspension. The variant calculation results for various parameters of the axial AMB control system are presented. Comparison of these results with experimental data confirms approach accuracy and practical applicability. The advantage of the proposed analytical method is high accuracy with low dimensionality and resource consumption. This enables the AMB optimal design with a large number of variable geometric and physical parameters, as well as the control law parameters. The approach avoids a large number of field experiments.