Research On Structure Parameter Design And Control Of Couple-Piece Type Radial-Axial Six-Pole Hybrid Magnetic Bearing

A magnetic bearing is a new type of high performance bearing which can realize no direct contact between stator and rotor by using magnetic field force.It has many advantages such as high speed and high precision,no friction,long life and so on.At present,the application fields of magnetic bearings include high-speed electrical spindle,flywheel energy storage,agricultural wind power generation,life and medical treatment,aerospace and so on.And now it have a broad application prospect.In order to reduce the cost and power consumption of magnetic bearings,inverter-driven three-pole magnetic bearings have become a research hotspot in recent years.However,the asymmetry of the radial space of the three-pole structure leads to the nonlinearity of suspension force and coupling in the radial freedom.In order to solve these shortcomings,referring to the symmetry of the traditional eight-pole or four-pole magnetic bearing,and to make full use of the magnetic circuit,a couple-piece type radial-axial six-pole hybrid magnetic bearing(HMB)is proposed.Modeling,parameters design,suspension force characteristic analysis,high performance control and experiment are studied.The main contents are listed as follows:1.The origin and development of magnetic bearings are reviewed according to the time,including domestic and foreign research progress.The magnetic bearing is summarized from the aspects of the composition of the whole system,the classification and the specific application of the magnetic bearing in various fields,as well as the control technology of the magnetic bearing at present.2.The structure and the principle of the couple-piece type radial-axial six-pole hybrid magnetic bearing are introduced,and the mathematical models are established respectively.On the basis of the mathematical model,the expression of the suspension forces of the couple-piece type radial-axial six-pole hybrid magnetic bearing are derived,and the linearity,coupling and maximum bearing capacity of suspension forces are compared with three-pole HMB respectively.The correctness of the structure parameters design and the suspension force characteristic research are verified by finite element software.3.In order to improve the control effect of magnetic bearings,an adaptive fuzzy controller is designed according to the characteristics of the couple-piece type radial-axial six-pole hybrid magnetic bearing.At the same time,a particle swarm optimization(PSO)algorithm is used to optimize the selection of expansion factor.And the simulation results in Matlab/Simulink are compared with the simulation results of the traditional PID controller and fuzzy controller in detail,which show the superiority of the adaptive fuzzy controller based on particle swarmoptimization.4.A couple-piece type radial-axial six-pole hybrid magnetic bearing digital control system is constructed.The control hardware mainly includes three modules: DSP minimum system,drive circuit and displacement detection circuit.The software part mainly includes the main control program,suspension force interrupt subroutine and man-machine interface.Finally,based on the designed experimental system,the linearity of suspension forces,start and anti-interference of experiments are carried out.