A Study On The Fundamental Theory Of Stator Permanent Magnet Bearingless Flux-switching Motor

With the development of the society and the production need,high speed and ultra-high speed,large capacity electric drive has been more and more widely used,but the centrifugal force of rotor will rise with speed increases.The permanent magnet fixation of traditional motors in which permanent magnets are on the rotor become more and more difficult,at the same time it makes friction force of the mechanical bearing increasing which supports the rotor that exacerbates the mechanical vibration and noise,causing the motor fever,shortening the service life of the bearing,and in some special applications,such as high clean environment,toxic,space,radiation and so on,mechanical bearing maintenance is a problem.Flux-switching permanent magnet machine(FSPM)is the staor permanent magnetic type motor,which permanent magnets are placed on the stator,the rotor neither have permanent magnets,nor windings.Compared with the traditional rotor permanent magnetic type motor,stator permanent magnetic type motor has simple rotor and it can dissipate heat easily,overcomes the fixation of permanent magnets in high speed situaton.This paper will apply bearingless technology to FSPM and make research on the fundamental theory of stator permanent magnet Bearingless flux-switching motor.The main content of this paper is as follows:This paper describes study background and significance of this subject,introduces home and abroad research status of bearingless induction motor,bearingless permanent magnet synchronous motor and bearingless switched reluctance motor,based on this,it proposes stator permanent magnet bearingless flux-switching motor.Stator permanent magnet bearingless flux-switching motor has advantages of high efficiency and simple rotor structure at the same time,it is different from the existing bearingless motor technology significantly,so further exploration is necessary for this kind of bearingless motor.The mathematical model is constructed in this paper base on the analysis of complete modulation law of the stator permanent magnet bearingless flux-switching motor levitation winding on the air gap magnetic field,further,the relationship between the levitation winding current and the levitation force is determined.A variety of levitation force waveform under theparticular levitation winding structure is got by Matlab,and optimum levitation winding connection is selected by comparing the levitation force waveform.A three phase stator permanent magnet bearingless flux-switching motor by 3 kw,3000 r/min is designed in this paper,and the initial parameters including the size of the stator and rotor core,the permanent magnet and armature winding number of turns are determined according to the general design method of flux-switching permanent magnet machine.On the basis of the initial parameters,the parameterized model is set up by Ansoft.With the air gap flux density,electromagnetic torque and levitation force as the goal,the main of the motor parameters are optimized,and the optimization is test through simulation of levitation performance.Finally,basic performance of the stator permanent magnet bearingless flux-switching motor in kind is test.This paper deduces the mathematical model of rotation control and levitation control,on this basis,the rotation control strategy and the levitation control strategy on the motor is put forward.The simulation model is set up by MATLAB at the same time,and the feasibility of the control strategy is verified by analyzing the simulation results.