Design and Implementation of Novel Homopolar Magnetic Bearings Incorporated in Reaction Wheel for Satellite Attitude Control

A novel compact-design homopolar magnetic bearing system is proposed for reaction wheels in satellite applications. The magnetic bearings, with low core loss, can increase the designed speed of the reaction wheel, thereby reducing the rotor inertia and wheel mass required to achieve attitude control. The proposed magnetic bearings are capable of producing both radial and axial suspension forces using a simple L-shaped core structure. The magnetic bearings thus not only simplify the control logic, but also enable the radial and axial forces to be independently controlled. A magnetic circuit model of the proposed bearing system is first derived and validated by finite element simulations. The practical feasibility of the bearing system is then confirmed experimentally using a prototype reaction wheel, which is designed through the developed magnetic circuit model.