Research On Modeling And Fuzzy Active Disturbance Rejection Control Of Radial Six-Pole Active Magnetic Bearing

A magnetic bearing is a kind of high performance non-contact bearing which produces electromagnetic force by rotating magnetic field to make the rotor suspended in space so that the stator and rotor do not produce mechanical contact.It has many advantages,such as long service cycle,low wear and no lubrication.It has broad application prospects in high-tech fields such as aerospace,wind power generation,life science and so on in the future development of high-tech fields,such as aerospace,wind power generation,life science and so on.Universal four-or eight-pole magnetic bearings have been studied by scholars for many years,and have many disadvantages such as volume redundancy,high cost of actuators,low working efficiency and so on.In view of these disadvantages,the dissertation studies a six-pole(6-pole)radial active magnetic bearing structure,which is driven by a three-phase inverter,which has the advantages of small volume,high spatial utilization and mature technology,etc.In this dissertation,the theoretical and experimental research is carried out from the key technologies such as parameter design,mathematical model and control method.The main contents and research achievements are listed as follows:Firstly,the origin and development history of magnetic bearings at home and abroad are summarized,the structure and working principle of magnetic bearings are described,the magnetic bearings are classified,the development trend of magnetic bearings in the future and the key technologies to be solved are prospected.The important function of the control method to the magnetic bearing system is introduced,and some control methods and their respective advantages and disadvantages are described.At last,the purpose and significance of the subject research are summarized,and the contents of this thesis are given.Secondly,a 6-pole radial AMB is proposed.The design structure and working principle of the 6-pole radial magnetic bearing are described.The parameter design of the 6-pole radial magnetic bearing is carried out.The finite element analysis is carried out according to the designed parameters,and the feasibility of the design is verified.Because the 6-pole radial AMB is similar to the bearingless motor in structure and suspension principle,the mathematical modelof radial magnetic bearing is calculated by using Maxwell tensor method,and the generality and accuracy of this method are analyzed.Thirdly,the basic theory of Active Disturbance Rejection Control(ADRC)and fuzzy control is analyzed,and a fuzzy ADRC control strategy combining the advantages of ADRC and fuzzy algorithm is put forward.Based on the two-degree-of-freedom 6-pole magnetic bearing,a fuzzy auto-disturbance rejection controller is designed.The structure and composition of the controller are introduced,and the parameters are self-tuning.Then,the floating,disturbance and decoupling of the six-pole radial AMB are simulated by MATLAB,and the experimental results are compared with those of the traditional PID control in detail.Finally,The digital test system of 6-pole radial AMB is constructed,and the general control structure diagram of the system is introduced.The hardware modules of the digital control system are designed and fabricated with TMS320F2812 as the digital control core,including the DSP system circuit board,the three-phase power drive circuit board and the conditioning circuit board.Then,the design flow of the software part is shown,and the programming of the main module and the design of the human-computer interface are completed.The lifting and disturbance tests are carried out on the test platform to realize the stable suspension of the rotor,and the rationality of the six-pole radial AMB structure and the stability of the system are verified.