Research On Permanent Magnet Assisted Bearingless Synchronous Reluctance Motor And Its Decoupling Control

In order to solve the problems of low torque density,low power factor,high torque ripple and high suspension force pulsation for traditional bearingless synchronous reluctance motors(BSynRMs),a novel permanent magnet assisted bearingless synchronous reluctance motor(PMa-BSynRM)is proposed in this dissertation.The proposed PMa-BSynRM integrates many merits of permanent magnet motor,synchronous reluctance motor and magnetic bearing,it has wide application prospects in semiconductor industry,electric vehicle,life science,military and so on.The PMa-BSynRM is taken as the research object in this dissertation,the mechanism of torque and suspension force,mathematical modeling,rotor optimization design and decoupling control are explored and studied.The main research works and results are as follows:1.The development history of bearingless motors are summarized according to the key time nodes,the research status and development trend of BSynRM are expounded from the perspectives of motor optimization,decoupling and sensorless detection,and the significance and application prospect of PMa-BSynRM are described.Based on the proposed PMa-BSynRM structure,the operating principles of the PMa-BSynRM torque subsystem and suspension force subsystem are expounded,and the mechanism is verified by means of finite element software.Mathematical models of the radial suspension forces considering the influence of radial Lorentz force and rotor eccentric displacement are constructed,and the mathematical models of torque subsystem are derived.The mechanical structure of the PMa-BSynRM system with five degrees of freedom is proposed,and the PMa-BSynRM control block diagram is designed.2.In order to optimize torque density and power factor,the magnetic barrier layer number,air gap ratio,rotor rib width,auxiliary permanent magnet position and its dosage are optimized by ANSYS/Maxwell software,and the optimal motor model is obtained.On this basis,the electromagnetic characteristics of the constructed PMa-BSynRM model are analyzed,including the size,direction,controllability of the radial suspension forces,and decoupling performance between two sets of winding.The torque,suspension force and power factor of the PMa-BSynRM and traditional BSynRM are compared to verify the superiority of the designed motor.3.From the point of view of decoupling control,the problem that torque windings current value has great influence on suspension forces is solved.A neural network inverse system decoupling control method for the PMa-BSynRM is proposed by combining the inverse system control method with neural network.The reversibility analysis of the PMa-BSynRM system is carried out,the simulation model of the PMa-BSynRM is built and simulated in Matlab/Simulink to verify the robustness,decoupling and reliability of the decoupling control system.4.The hardware and software parts of PMa-BSynRM digital control system are designed respectively.The design scheme of DSP minimum power board,power drive boards and interface circuit are given in the part of hardware,and the main program and interrupt subroutine of control algorithm,and man-machine interface are designed in the part of the software.Finally,the digital control system is debugged and tested.