Sharing Suspension Windings Bearingless Switched Reluctance Motor And Its Control

High-speed motors are widely applied in social life,but the high-speed and ultra-high-speed operation of motors is limited by the wear and heating of traditional mechanical bearings.The appearance of bearingless motor broadens the research idea of high-speed motor.As a kind of bearingless motor,bearingless switched reluctance motor has such the advantages as simple structure,high reliability and easy to control.The sharing suspension windings bearingless switched reluctance motor has obvious advantages in the research field of bearingless motor such as,the outstanding motor structure which makes the torque and radial force decouple,low hardware cost and simple control method.In this dissertation,the sharing suspension windings bearingless switched reluctance motor is taken as the research object.And stable rotation and suspension control,design and optimization,and the establishment of saturated analytical model of the motor are delved into.The finite element model of the sharing suspension windings bearingless switched reluctance prototype was established.The electromagnetic characteristics of the prototype is analyzed,The characteristic verification experiment of the prototype is carried out.And the decoupling characteristics between torque and radial force on the structure of the sharing suspension windings bearingless switched reluctance prototype were verified.A control scheme that rotor suspension control is carried out with a certain phase rotation winding energized when the motor is operated in high speed is proposed to realize the decoupling of suspension forces in X and Y directions.The minimum speed required,when one phase rotating winding is energized,to adjust the suspension winding current for realizing the stable suspension of rotor is derived.Based on single-phase suspension control scheme,the dynamic simulation model of the sharing suspension windings bearingless switched reluctance motor is established by using software Matlab/Simulink.Simulation results verify the effectiveness of the proposed single-phase suspension control scheme.A radial displacement control strategy based on the improved model reference adaptive control was proposed to improve the rapidity and anti-disturbance ability of the suspension control system.The kinematics model of rotor radial displacement is derived.The radial displacement controller is improved,the rotor radial displacement model reference control scheme is designed.And the rotor radial displacement control system based on the improved model reference adaptive control strategy is built by using software Matlab/Sinulink.The stable rotation and suspension of the rotor is realized by the simulation.The simulation results show that the designed adaptive control system has better dynamic response and robustness than the traditional PID control system.It is verified that the designed adaptive control system has better dynamic response and robustness than the traditional PID control system.The suspension control scheme of sharing windings bearingless switched reluctance motor is studied.The radial displacement single closed-loop control system was built.And the rotor is suspended stably under the condition of motor starting,stable rotation at 1000 RPM and percussive disturbance in X and Y directions.A displacement-current double closed-loop control system is established.And the rotor stable suspension was realized under the condition of motor starting,stable rotation at6000 RPM and percussive disturbance in X and Y directions.The influence of prototype structural parameters on the motor performance was analyzed in detail.Based on the analysis results,the structure of the motor is designed and optimized,and the average static torque of the motor is improved and the torque ripple is reduced.A torque analytical model of switched reluctance motor considering saturation is derived.Based on the analytical relationship between magnetic flux density and magnetic field strength obtained by fitting,the relationship between magnetic permeability and magnetic field intensity is deduced.Based on the virtual displacement method,the air gap permeability and the core permeability of each part in the motor are deduced.According to the equivalent magnetic circuit method,the motor flux linkage is derived.The magnetic co-energy generated when the motor is energized and torque analytical model of switched reluctance motor considering magnetic saturation are further derived.The validity of the model is verified by comparing with the finite element results.The control system of switched reluctance motor based on torque analytical model is established.The effective control of motor torque is realized by simulation and experiment.The saturation model can also be extended to the bearingless switched reluctance motor to provide theoretical basis for its control and optimization.