Axial Flux Machine Using Passive Magnetic Bearing with Axial Magnetization

Decreasing the maintenance cost and power losses in Axial Flux Permanent Magnet machine using Passive Magnet Bearing instead of mechanical ball bearing is the purpose of this paper. Two structures of Passive Magnetic Bearing are applied, and the magnetic forces and stiffness are analyzed. The best structure is selected according to the safety, mechanical consistency and economical charges. A balance point is found where the magnetic force of Passive Magnetic Bearing and magnetic force between rotor and stator structure, neutralize each other. Also, magnetic forces are investigated according to the displacements of the middle ring in Passive Magnetic Bearing and according to different air gap width between rotor and stator in the motor. According to the symmetry of Axial Flux Permanent Magnet motor, the motor is modeled using three-dimensional finite-element method. On the other hand, based on the axial symmetry around z-axis in Passive Magnetic Bearing, the bearing is modeled using two-dimensional finite-element method. These simplifications will help the calculation of the magnetic force and stiffness in the least computation time