| A bearingless induction motor(BIM)adds a set of windings in the stator structure of traditional induction motor to produce suspension force,realizing suspension operation.It has excellent characteristics such as no friction and wear,no lubrication and long service life and has shown great application value in the field of precision machinery manufacture,flywheel energy storage,aerospace,life science and others,which is one of key studies in electrical drive area and magnetic suspension technique.With the support of the National Natural Science Foundation of China(51475214),the suspension principle of BIM,the establishment of mathematical model,the analysis of slot rotor width on motor perforrmance,rotor skin effect and digital control system are studied in this thesis.The detailed contents are as follows:Firstly,the research background and research status of bearingless motor are summarized,and the development trend of BIM is briefly introduced.Based on the analysis of suspension principle of BIM,the expression of suspension force is deduced and the mathematical model of BIM is established.Then,the BIM control system based on rotor field orientation is constructed and simulated.It lays a foundation for further research on BIM structure design and high performance control.Secondly,the rotor slot width affects the distribution of magnetic field in the teeth and yoke of the stator and rotor,influencing stable operation of motor.To study this problem,the finite element model of motor is constructed and the starting performance,load characteristics and suspension performance are discussed by the finite element method.The appropriate slot width is obtained by comparing the effects on various performances of the motor.Then,aiming at the problem of rotor parameter variation caused by skin effect during motor starting and running,the curve of rotor parameter variation is calculated by finite element method.The influence of rotor parameters on magnetic field orientation and suspension force of BIM control system is analyzed.Based on this,a parameter identification model based on least square method is designed and applied to BIM control system.The proposed control system is simulated with Matlab/Simulink.Finally,a BIM control experimental platform with DSP TMS320F2812 as main control chip is built up.The hardware design scheme and software design flow chart of the digital control system are given.The speed test and rotor radial displacement test are carried out.The experimental results show that the motor has good speed response and suspension characteristics. |
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