| High Speed and Super-high Speed electric drive system has been used more and more widely in modern society.But the centrifugal force imposed on the rotor rises with the increment of rotor speed and force of friction between rotor shaft and mechanical bearing which supports shaft increases.So that electric motor overheating problem is caused by aggravated mechanical vibration,the efficiency of the electric drive system could be severely influenced.Not only the life of mechanical bearing might be shorten,but also increment of speed could be limited.In some case,the maintenance of bearing is a big problem.Therefore,bearingless motor,a new type of electric machine in which the radial electromagnetic forces can be produced with rotor rotation simultaneously so that rotor rotation without friction,lubrication and abrasion can be achieved,emerges at a historic moment.Flux-switching permanent magnet machine(FSPM)is a new stator-permanent magnet type motor which permanent magnets are placed in the stator and the rotor neither have permanent magnets nor windings.The application of bearingless technology to flux-switching permanent magnet machine can make full use of advantages of FSPM including simple structure,high power density and high efficiency.Based on these reasons,this paper mainly focuses on research of stator permanent magnet bearingless flux-switching machine.First,the basic structure of one 12/10 type FSPM is introduced,the conception of flux switching is described,the working principle and electromagnetic characteristics of the motor are analyzed in this paper.Then,the mathematical model of one typical three phase FSPM under different coordinate system is analyzed.On the basis of above,a novel double winding structure of FSPM is proposed in this paper.Principle of suspension is analyzed by using Ansoft/Maxwell combined with the finite element method.The suspension force mathematical model of this motor including rotor under normal condition and eccentric condition is established,and the connection of these two conditions of rotor is analyzed.In order to solve the over current problem in the control of one six phase single winding bearingless flux-switching machine which proposed before,after the analysis of the relationship between the current of suspension winding,the suspension force and the rotor position angle,a novel control strategy of suspension force in which orthogonal suspension windings work in time-sharing turn is proposed in view of obtaining maximum suspension force per ampere,and a novel method which the suspension force coefficient can be calculated and extracted by looking up tables is introduced.Then,vector control strategy based on space vector modulation aims to achieve tangential rotation of rotor is proposed after the introduction and analysis of the theory of vector control and space vector modulation.Then,the simulation control system is established by Matlab/Simulink and the simulation research on the performance of the system has been done,the results verify the feasibility of the strategy.In order to validate the proposed control strategy by experiments conducted,two set of high-performance,good stability hardware and software systems using two TMS320F2812 DSP as the core have been established.According to the different control requirements of the two sets of windings,the corresponding hardware and software system are designed to achieve the control of the corresponding winding.In aspect of communication,RS232 is used to translate data between two systems.And motor drive control system is experimentally investigated and analyzed. |
PDF Full Text Request