Structure and Suspension Force Analysis of Six-Pole Five Degrees of Freedom AC Hybrid Magnetic Bearing

Abstract

A novel six-pole five degrees of freedom (5-DOF) ac hybrid magnetic bearing (HMB) is put forward in this article, which can obtain large suspension force density, high critical speed, and reduce the nonlinearity of radial suspension force. First, the structure and suspension principle are introduced in detail and then the mathematical models of the radial and axial suspension force are derived based on the equivalent magnetic circuit analysis. Second, the main parameters are designed according to the given maximum radial and axial bearing capacities. Finally, the prototype of the six-pole 5-DOF ac HMB is established by the 3-D finite-element analysis software Magnet. Moreover, the electromagnetic analysis is carried out to verify the rationality of the magnetic circuits and suspension mechanism. Furthermore, the force-current relationships are calculated. The research results have shown that the proposed six-pole 5-DOF ac HMB has reasonable structure and good suspension performances.