Research On Identification Methods For Support Parameters Of The Magnetic Bearings

As the new support element, the magnetic bearing has incomparable advantages that traditionalbearings don’t have, and it has been applied to many fields. Due to its stiffness and dampingparameters adjusted online, supporting characteristics of magnetic bearing have a more importantinfluence on the dynamic characteristics of the system. Therefore, identification of supportingparameters of the magnetic bearing plays an important role in the magnetic suspension technologyresearch. This paper aims to analyze identification methods of magnetic bearing support parametersfrom rotor responses due to imbalances and impact loads.Beginning with the structure and working principle of magnetic bearings-rotor system, thedefinition of the stiffness and damping parameters of magnetic bearings is presented. Then thelinearization of the electromagnetism force analysis, the formula derivation process and the relationbetween support parameters and the critical speed are analyzed.The basic principles of the boundary element method is Introduced briefly. Identification ofmagnetic bearing support parameters which include direct and coupled parameters, is carried outthrough the finite element simulation, and the influence that different imbalance masses have onparameters is discussed. In experiment, the method is applied to identify the direct and coupledparameters of magnetic bearing. Finally, the relationship among support parameters, the imbalancemass, the excitation frequency is analyzed.In identification method based on the measurements of impact response, the hammer is used asthe excitor. The transient impact force is applied to the rotor, then the excitation and the responsecollected are substituted into the theoretical formula to calculat supporting parameters.In order to toverify the feasibility and accuracy of the method, simulation analysis of the FE model of the AMBsystem is carried out in MSC.Nastran and Matlab. Finally, the paper focuses on the experimentidentification of AMB, the filtering method is detailed illustrated to filter the residual imbalanceresponse and high-frequency interference. Stiffness and damping parameters of the magnetic bearingare identified under a certain speed after treating and acquiring the amplitude and phase ofdisplacement response.