Radial Force-Current Characteristic Analysis of Three-Pole Radial-Axial HMB

The magnetic bearings are important component of magnetic suspension flywheel system. As three-pole magnetic bearings can be driven by three-phase inverter which is low power consumption, small volume and low cost, the three-pole magnetic bearings have attracted wide attention of scholars in the world. However, the force-current characteristic of the radial suspension force is nonlinear because of three-pole structure and driven by the inverter, and it is difficult to control the displacements of the three pole magnetic bearing accurately. In this paper, the radial force-current characteristics of the three-pole radial-axial hybrid magnetic bearing (HMB) are analyzed by using non-linearized mathematical model, and are verified by finite element method (FEM). The relationship between radial suspension forces and control currents are measured on a test prototype. The experiment results are consistent with the results of theoretical analysis and FEM verification.