Bearingless Induction Motor And Its Sliding Mode Variable Structure Control Against Load Disturbance

Bearingless Motors,with the advantages of no friction,no extra lubrication,small noise and long service life,have shown great application value and development potential in the fields of flywheel energy storage,high speed hard disk,aseptic workshop,life science,Aeronautics and Astronautics and so on.It is a great innovation for the electric bearing support motor of the transmission machine.Compared with other types of bearingless motors,A bearingless induction motor(BIM)with squirrel cage rotor has the advantages of simple structure,high mechanical strength,easy to realize weak magnetic speed regulation,and relatively cheap price,and is one of the hot topics in the field of bearingless motor and special power transmission.Under the support of the National Natural Science Foundation of China(51475214)and the Natural Science Foundation of Jiangsu(BK20141301),the operation mechanism of BIM,the establishment of mathematical model,the control of load disturbance rejection and the realization of the digital control system are studies in this paper.The specific contents are as follows:Firstly,the research background,research status,application field,development trend and sliding mode control of BIM are summarized.The operation mechanism of BIM is described,and its complete mathematical model is established.Based on this model,BIM control system based on air gap magnetic field orientation control is constructed.Secondly,the fractional calculus is introduced and the speed controller based on fractional order integral sliding mode is designed to solve the problem that the control performance of PID control and ordinary sliding mode control is poor in load disturbance.In addition,in order to further improve the dynamic performance of the system,a novel extended sliding mode observer(NESMO)is designed,and the observation value of the load torque is fed into the sliding mode controller.The BIM control system is simulated and analyzed in Matlab/Simulink platform.The simulation results show that the control strategy not only has good dynamic and static performance,but also effectively improves the system’s anti-load disturbance capability.Finally,the hardware and software system are designed with TMS320F2812 DSP,and the experimental platform of BIM digital control system is built on this basis,and the experiment of suspension and dynamic performance are carried out.The experimental results show that the adopted control strategy can not only realize rotor stability rotation and suspension,but also have good operation quality.