| The magnetic suspension bearingless motors generate both electromagnetic torque and magnetic levitation forces for the rotor suspension by the motor itself. The bearingless motor is comparatively suited for using as artificial heart blood pump motor due to the advantages of without mechanical wear and noise, structure compact and contactless.The work in this thesis focuses mainly on the basic theory of bearingless motors, magnetic levitation forces and their decoupled control with electromagnetic torque as well as air gap dynamic detection. Three parts are included.First of all, the characteristics and technology nodi of the bearingless motors are analyzed. Four popular types of rotor structure and their effects on characteristics of bearingless motor are compared. A novel bearingless motor with decoupling relationship between magnetic levitation force and electromagnetic torque is proposed and a prototype machine are designed and built.Secondly, the operation principles of various displacement sensors are studied. The dynamic and static characteristics of the eddy-current sensor are emphatically investigated. The factors of producing error and method of eliminating error have analyzed indetails.Finally, the principle of phase-locked-loop for speed control is discussed. The control methods of torque and magnetic levitation force are studied experimentally on a prototype bearingless motor. Based on the analysis of shortcomings of the analog control system, a digital control system is proposed.
|
PDF Full Text Request