Analysis And Measurement Research On Electromagnetic Field For Magnetic Bearings

Electromagnetic field distribution is one of the most important parts in research of magnetic bearings. As there are many nonlinear problems and the electromagnetic-thermal-structural coupling problem is very complicated, traditional magnetic circuit analysis cannot make a comprehensive solution to these problems. Finite Elements Analysis (FEA) and measurements of electromagnetic field distribution in magnetic bearings are presented. Optimal design of magnetic bearing based on electromagnetic field analysis, electromagnetic interference and screen have been studied.Electromagnetic field distribution of radial magnetic bearings and axial magnetic bearings in magnetic levitated Hard Disk Drive are analyzed and calculated through FEA method and ANSYS software; Electromagnetic field is measured on radial magnetic bearing stator of magnetic levitated Hard Disk Drive, the results of FEA and measurement are compared, the basic principle of electromagnetic field distribution is concluded.Basic structural parameters of magnetic bearings are analyzed and principles of selecting these parameters are introduced. Basic characters of magnetic bearings are analyzed, including static working point, the largest magnetic force and power losses etc. Assigning maximal magnetic force as objective function, the optimal design of radial magnetic bearing in magnetic levitated Hard Disk Drive is completed, and the results of optimal design are presented.Magnetic flux density distribution of common Hard Disk is measured, magnetic screen method for magnetic levitated Hard Disk Drive is evaluated through FEA and magnetic leakage at the disk is measured. The conclusion is that the magnetic leakage will influence the data's writing and reading, more effective magnetic screen should be developed.