Analysis Of Nonlinear Vibration Characteristics Of Electromagnetic Damper-Rotor System

Electromagnetic damper is a new structure integrating electromagnetics,mechanics,and control.As a new type of vibration suppression measure,it uses electromagnetic force to control the vibration of the rotor system.It has the advantages of no friction,no need for lubrication,and long life.,Gradually applied to practice.When the electromagnetic damper is applied to the rotor system to form an electromagnetic damper-rotor system,as a new type of rotor vibration suppression system,the study of its nonlinear vibration characteristics has important theoretical and practical significance.This paper is devoted to studying the nonlinear vibration characteristics of electromagnetic damper-rotor system.For the electromagnetic damper-single-disk rotor system,the Lagrange equation is used to establish the system dynamics equation,and the influence of the parameters on the system dynamics is studied by numerical solution.The stability of the system solution and the influence of parameters on the stability are studied through analytical solutions.First,briefly introduce the formation mechanism of electromagnetic force.According to the Maxwell attraction formula,the conductive magnetic attraction is derived.At the same time,the fluctuating current caused by the vortex of the passive electromagnetic damper and the active electromagnetic force with PD closed-loop control are derived,considering that the electromagnetic damper is four magnetic poles,the electromagnetic force considering the cubic nonlinear term is obtained.Research on the influence of system parameters on system dynamics is carried out.Using the established dynamic equation of the electromagnetic damper-rotor system,the nonlinear characteristics of the system are first analyzed in detail,and then the dynamic response of the system under different parameters is solved numerically.Through the amplitude-frequency response curve,time history,axis trajectory,bifurcation diagram and other analysis parameters,the influence law of the system dynamics is found.The study found that: Increase the bias current,the amplitude of the passive electromagnetic damper-rotor system decreases,and the bistable interval decreases;the amplitude of the active electromagnetic damper-rotor system decreases,and the resonance interval shifts to the left.Increasing the proportional coefficient will shift the resonance interval of the active electromagnetic damper-rotor system to the right,and the bistable phenomenon will disappear;increasing the differential coefficient will reduce the system amplitude.By comparing and analyzing the dynamic behavior of the active and passive electromagnetic damper-rotor system,it can be seen that the active type can adjust the controller parameters to reduce the system amplitude and at the same time adjust the resonance interval.Finally,the stability of the electromagnetic damper-rotor system is analyzed.The analytical solution of the active and passive electromagnetic damper-rotor system is obtained through the multi-scale method,and the analytical results are compared with the numerical results to verify the accuracy of the solution.Then analyze the stability of the stationary solution through the eigenvalues of the Jacobian matrix of the disturbance equation,and use the amplitude-frequency curve and amplitude response curve to analyze the influence of the system parameters on the stability.The study found that for the passive electromagnetic damper-rotor system,increasing the bias current reduces the unstable solution interval of the system.For the active electromagnetic damper-rotor system,increasing the proportional coefficient and the differential coefficient will reduce the unstable interval of the system;increasing the bias current will shift the unstable solution interval of the system to the left.