Research of Magnetic Fields in New Design of Homopolar Magnetic Bearing

Abstract

This work presents a new design of homopolar active magnetic bearings. The authors managed to eliminate the key shortcomings characteristic for the known technical solutions, in particular, a new model features a reduced active magnetic bearing axial length, less saturated stator core and reduced losses in permanent magnets. In this paper provided the research by finite element methods of a new design homopolar active magnetic bearing in a 3D statement and established that there was virtually no influence of bias permanent magnet fields on the rotor pole permanent magnet field and electric machine output characteristics. In addition, the authors identified that the opposite direction of the bias permanent magnets magnetization of homopolar active magnetic bearing weakens the magnetic field on one of the rotor poles by 8-10%, which does not occur at the codirectional bias permanent magnet magnetization. The rotor magnetic field visualization showed the same results as the calculations obtained by finite element methods. Furthermore, the article presents the results of the mock-up model tests of the developed homopolar active magnetic bearings and provides evaluation for the bias permanent magnets influence on the electric machine output voltages in the generator mode. The obtained results of experimental research virtually coincide with the calculation results obtained by finite element methods. That is proves the efficacy of given models and developed structure of a homopolar active magnetic bearing is an advanced technical solution in the magnetic bearing systems which widens their application scope.