5-Degree of Freedom Active Position Control of an Axial Self-bearing Motor with Six Concentrated Stator Windings

In recent years, pumps of magnetic bearing type have been widely developed because that a magnetic bearing motor need not lubrication oil and has no friction loss. For downsizing and reducing cost of magnetic bearings, an axial self-bearing motor (ASBM) is developed in this paper. The ASBM is composed of two identical stators and on disk rotor which is sandwiched by the stators axially. Each stator has six concentrated winding coils which are driven by separate power amplifiers. Based on control principle of the developed ASBM, 5-degree of freedom (5-DOF) active position control system is designed to realize axial control, tilt control and radial control simultaneously. For generating rotation torque, open-loop torque control method and closed-loop torque control method are applied, respectively. After implementing the above mentioned control method, experimental results of rotation test are shown to verify the practicability of the developed ASBM and effectiveness of the designed control system.