| Bearingless induction motor(BIM)is a new type of motor that combines magnetic bearings with high-speed motors.In the past ten years,with the continuous development of power electronics technology,microelectronic technology and modern control theory,the BIM structure and related control strategies have been rapidly developed and improved.In highspeed precision machining,electromechanical batteries,special robots,life sciences,semiconductors,etc.Manufacturing and other fields show broad application prospects and have high practical application significance.Compared with other motors,BIM has a series of advantages such as simple structure,convenient operation,low cost,convenient use and maintenance,high operating efficiency,no friction,no wear,high precision,etc.,and has become a hot spot in the research field of bearingless technology.In order to further solve the problems related to BIM in practical applications and realize the savings of BIM operation in high-speed and ultra-high-speed environments,this thesis discusses its suspension principle,mathematical model,finite element optimization,nonlinear flux modeling,and self-reaction Relevant researches have been conducted on disturbance controller,speed sensorless operation,position sensorless operation,digital control system,etc.The specific research content consists of the following parts:1.According to the principle of the motor,the relevant BIM levitation force mechanism is introduced,the mathematical formulas of Maxwell’s force and Lorentz force are derived in detail,and the mathematical model of the BIM when the rotor is eccentric and non-eccentric is established.At the same time,the parametric modeling of BIM based on Maxwell finite element was performed.In order to solve the problems of BIM operation efficiency and stable suspension,2.Aiming at the non-linear characteristic relationship among BIM flux linkage,torque winding current,suspension winding current and eccentric distance of the rotor,in order to accurately reflect the actual characteristics of the motor,a new type of optimization based on the gray wolf algorithm(Grey Wolf Optimizer Least Squares Support Vector Machines(GWOLSSVM).A non-linear model between the magnetic flux and the torque winding current,the floating winding current,and the eccentric distance of the rotor is established by the least squares support vector machine.To solve the problem of the error between the magnetic flux obtained from the model and the actual magnetic flux,GWO The optimal kernel parameters and regularization parameters of LSSVM were optimized,and the method was verified by Matlab / Simulink software.The results show that the method has strong generalization ability,which reduces the calculation time and makes the obtained magnetic The chain model is more accurate.3.Aiming at the characteristics of BIM multivariable,non-linear and strong coupling,in order to achieve stable and accurate control of BIM,a BIM control strategy based on Active Disturbance Rejection Contro(ADRC)is proposed.This control system uses the two-channel compensation structure of Extended State Observer(ESO)to modify the original system model to make the nonlinear and uncertain systems approximately linear and deterministic.By using ESO to estimate the total interference of the system in real time,and using ADRC to compensate the interference in time.Aiming at the system’s dynamic performance and uncertain antijamming robustness,Space Torque Control(DTC)and Direct Suspension Control(DTC)based on Space Vector Modulation(SVM)are proposed.DSFC)method.Through Matlab / Simulink software simulation,this method can eliminate the steady-state tracking error to obtain good anti-interference performance.4.Aiming at the needs of BIM no-speed sensing control and no radial displacement sensing control,a speed and displacement recognition method based on Model Reference Adaptive System(MRAS)was proposed.In terms of BIM no-speed control,the instantaneous reactive power Qref and stable power Qest of the rotating part of BIM are applied to the reference model and the adjustable model respectively,the speed is identified by the PI controller,and the system is stabilized by using Popov’s superstability theorem Proof.In terms of BIM positionless control,the current of the floating winding in the steady state is used as a reference model and an adjustable model.Displacement identification is realized through a PI controller.The stability of the system is verified using Popov’s superstability theorem.In order to improve the overall system Dynamics,it is used for direct suspension force control.Through Matlab / Simulink software simulation,this method has high speed and position recognition accuracy,and ignores problems such as saturation integration and stator resistance recognition.It also has good displacement tracking ability,good temperature stability,low noise and linearization.Large range and many other advantages.5.In view of the shortcomings of using current regulated pulse width modulation(CRPWM)inverters to achieve speed control and displacement control in BIM control systems,a space vector pulse width modulation based on Space Vector Pulse Width modulation is proposed.Modulation(SVPWM)BIM vector control strategy,adds current inner loop to BIM torque and suspension winding respectively,which improves the overall control performance of the system.A BIM digital control system with TMS320F2812 digital signal processor DSP as the core was constructed,and related control board circuits,radial displacement interface circuits,current model feedback circuits,and photoelectric coding interface circuits were designed,and the BIM speed and Experiments were performed on the suspension system,and the experimental waveforms were given and the experimental results were analyzed.The experimental results show that the designed digital control system based on SVPWM algorithm can realize the stable operation of BIM,and has good dynamic and static characteristics. |
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