| The rotor contact support mode of traditional motors can not meet the requirements of high speed and high precision operation,which restricts the development of motor in the direction of high speed,high precision,high efficiency,long service life and maintenance free.A bearingless permanent magnet synchronous motor(BPMSM)can realize the suspension operation of the rotor,get rid of the problems caused by mechanical bearings,and has broader application prospect than traditional motors in many high-tech fields,such as life science,aerospace,flywheel energy storage and so on.In order to reduce the iron loss of BPMSMs,improve its energy transmission efficiency,eliminate the torque ripple caused by cogging effect,reduce the unbalanced magnetic pull force caused by rotor eccentricity,and reduce the suspension operation loss of the system,an outer rotor coreless BPMSM(ORC-BPMSM)is proposed in this dissertation.An ORC-BPMSM is a kind of motor with the coreless structure in a BPMSM.It has not only the excellent characteristics of bearingless motors,such as no friction and wear,high critical speed,but also the advantages of coreless permanent magnet motors,such as strong overload capacity,no cogging torque,high efficiency.An ORC-BPMSM is taken as the research object in this dissertation,and the working mechanism,mathematical model,structural parameter optimization,electromagnetic characteristics,decoupling control strategy and digital control system are studied.The followings are the principle work and achievements of this dissertation:1.The research background and significance of bearingless motors are introduced,and the development history of bearingless motors according to the time node is summarized.The research status of coreless permanent magnet motors is summarized.The research significance,research status and future development trend of ORC-BPMSMs are introduced.2.The basic structure of the ORC-BPMSM is designed.The composition of electromagnetic force in the ORC-BPMSM and its generation principle of radial suspension forces are analyzed.The mathematical models of radial suspension forces considering rotor eccentricity are established by Maxwell tensor method,and the torque mathematical model is established by virtual displacement method.3.The basic structural parameters of the ORC-BPMSM are determined by using the theoretical formula of motor,the design experience of related motor and the finite element software.The 2D finite element analysis model of the ORC-BPMSM based on the designed parameters is established,and its electromagnetic characteristics are analyzed.From the finite element results,the designed motor parameters meet the operation requirements of the ORC-BPMSM,and can realize the stable operation of the ORC-BPMSM.The torque,suspension force and losses of the outer rotor BPMSM with and without core structure are compared and analyzed.Compared with core structure,the output suspension force and torque of coreless structure are reduced in a small range,but the losses of the motor are reduced in a large range.The coreless structure has more advantages than the core structure in the application of higher requirements for motor transmission efficiency.4.The ORC-BPMSM is a strong coupling and nonlinear system.In order to realize the nonlinear decoupling control of the ORC-BPMSM,a generalized inverse decoupling control method based on least square support vector machine(LS-SVM)is proposed.On the basis of judging the existence of generalized inverse of the ORC-BPMSM,LS-SVM is used to train the data samples to fit the generalized inverse model of the ORC-BPMSM,which is connected in series with the original system to decouple several pseudo linear systems.The simulation model based on LS-SVM generalized inverse decoupling control method is established in Matlab/Simulink,and the simulation experiment is carried out.From the simulation results,the proposed LS-SVM generalized inverse decoupling control method can effectively realize the decoupling control of the ORC-BPMSM.5.The ORC-BPMSM digital control system is designed.DSP chip is used as the development core,and the hardware and software are designed respectively.The hardware design mainly includes three parts: DSP peripheral circuit,driving power board and speed and displacement detection circuit.The software is mainly written around the code of realizing the torque and suspension force of the ORC-BPMSM,and the related main control program and interrupt subprogram are designed.The experimental platform is built on the basis of software and hardware design,and the experimental research on the ORC-BPMSM is carried out.The experimental scheme based on LS-SVM generalized inverse decoupling control is proposed based on the construction of the experimental platform of digital control system. |
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