Research On Structure Design And Control System Of Bearingless Permanent Magnet Synchronous Motor

A bearingless permanent magnet synchronous motor(BPMSM)is a new type of motor which integrates the advantages of permanent magnet synchronous motor(PMSM)and magnetic bearing.The motor obtains excellent characteristics of PMSM: simple structure,high torque density,high power factor,high efficiency,etc.,as well as has merits of magnetic bearing: no friction,no wear,no lubrication,maintenance free,long life,and so on.With the rapid development of power electronic technology,microprocessor technology and control theory,the theory and application of BPMSM have made great progress.It has broad application prospects in the fields of flywheel energy storage,aerospace,medical equipment,chemical industry,precision machining and so on.Supported by Jiangsu Province key research and development plan,Jiangsu Province “333 Project” and Jiangsu Province "Qinglan project",this dissertation focuses mainly on the basic principle and mathematical model of BPMSM,the design and analysis of the body structure of BPMSM,hardware design,software design and the experimental study.The basic contents are as follows:1.The research background and research status of bearingless motors are expounded in detail.The development trend and application prospect of BPMSM are summarized.At the same time,the electromagnetic forces in BPMSM are analyzed in detail and the basic operating principles of BPMSM are described.The mathematical model of radial suspension force is derived based on the Maxwell tensor method.In addition,the mathematical model of electromagnetic torque is deduced.With the help of software Ansoft/Maxwell,the finite element simulation model is established to verify the mathematical model of the radial suspension force of BPMSM.The simulation results verify the correctness of the mathematical model.Finally,the rotor flux oriented control strategy of BPMSM based on SVPWM is designed,and the specific control block diagram is given.2.On the basis of BPMSM,the structure of the motor is improved,and a novel outer-rotor and coreless-stator-type BPMSM with Halbach array is proposed,which can be better applied to flywheel energy storage system.The structure and performance of Halbach array permanent magnet rotor are described in detail,and the structure of a new type of BPMSM is presented.The parameters of the motor are designed in detail,and the electromagnetic characteristics of the motor are analyzed.The rotor eddy current losses of BPMSM with different structures are compared.The comparison results show that the rotor eddy current loss of the coreless-stator-type BPMSM with Halbach array is the lowest.The simulation results show that the new type of BPMSM is very suitable for flywheel energy storage system.3.The hardware circuit of the BPMSM control system is designed in detail,which includes DSP minimum system,power drive circuit and interface circuit.The software part of the BPMSM control system is designed,and the detailed software flow chart is given.Finally,the hardware and software are integrated to build a complete experimental platform.The software and hardware are tested,and related experimental researches are made.The stable suspension operation of the experimental prototype is realized.