Parameter Design and Finite Element Analysis for AC 2-degree Freedom Hybrid Magnetic Bearing

In this paper, an AC 2-degree freedom hybrid magnetic bearing (HMB) is proposed, which is driven by a 3-phase AC power inverter. The configuration and the operating principle producing magnetic suspension forces of the AC 2-degree freedom HMB are introduced. The flux path is calculated by using the method of equivalent magnetic circuit and the mathematics models of the axial and radial magnetic suspension forces are deduced. The methods on parameter design and calculation of the innovated magnetic bearing are presented in detail. The experiment prototype of the innovated bearing is designed and the practical prototype's parameters are given. The feasibility and the correctness of the theoretical methods for the configuration, magnetic path and maximum loads capacity of the AC 2-degree freedom HMB are verified by using a 3D-FEM software (Maxwell 3D of ANSOFT). The theoretical approach and finite element simulated experiment have shown that the mechanical structure and magnetic circuit of this magnetic bearing are legitimacy. This AC 2-degree freedom HMB can be applied in high speed machine tool spindle with lower manufacturing and operation costs.