Dynamic Stiffness Analysis and Experimental Verification of Axial Magnetic Bearing Based on Air Gap Flux Variation in Magnetically Suspended Molecular Pump  

作　　者：Jinji Sun Wanting Wei Jiqiang Tang Chun‑E Wang 

机构地区：[1]Key Laboratory of Fundamental Science for National Defense,Novel Inertial Instrument and Navigation System Technology,School of Instrument Science and Opto‑Electronics Engineering,Beihang University,Beijing 100191,China [2]State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China [3]Beijing Institute of Automatic Control Equipment,Beijing 100074,China

出　　处：《Chinese Journal of Mechanical Engineering》2020年第4期139-149,共11页中国机械工程学报（英文版）

基　　金：Excellent Youth Science Foundation of China(Grant No.51722501);National Natural Science Foundation of China(Grant No.51575025);National Natural Science Foundation of China-Youth Science Foundation(Grant No.61603052);Opening Foundation of State Key Laboratory of Advanced Welding and Joining(Grant No.AWJ-20-R02).

摘　　要：Current and displacement stiffness are important parameters of axial magnetic bearing(AMB)and are usually considered as constants for the control system.However,in actual dynamic work situations,time-varying force leads to time-varying currents and air gap with a specific frequency,which makes the stiffness of appear decrease and even worsens control performance for the whole system.In this paper,an AMB dynamic stiffness model considering the flux variation across the air gap due to frequency is established to obtain the accurate dynamic stiffness.The dynamic stiffness characteristics are analyzed by means of the dynamic equivalent magnetic circuit method.The analytical results show that the amplitude of current and displacement stiffness decreases with frequency increasing.Moreover,compared with the stiffness model without considering the variation of flux density across the air gap,the improved dynamic stiffness results are closer to the actual results.Through the dynamic stiffness measurement method of AMB,experiments of AMB in magnetically suspended molecular pump(MSMP)are carried out and the experimental results are consistent with theoretical analysis results.This paper proposes the dynamic stiffness model of axial magnetic bearing considering the variation of flux density across the air gap,which improves the accuracy of the AMB stiffness analysis.

关 键 词：Axial magnetic bearing(AMB) Dynamic stiffness Magnetically suspended molecular pump(MSMP) 

分 类 号：TH133.3[机械工程—机械制造及自动化]