Analysis Of Radial Vibration Of Flywheel Rotor System Supported By Nonlinear Electromagnetic Force

Magnetic suspension flywheel energy storage system is a mechanical device which uses electromagnetic bearing support and flywheel rotation for energy storage.It has the characteristics of long service life,no contact support and low energy loss,and has a wide application prospect.Taking the radial vibration of magnetic suspension flywheel energy storage system as the research object,this paper analyzes the influence of nonlinear electromagnetic force on the radial vibration of flywheel rotor system.Firstly,according to the basic principle of differential electromagnetic bearing,a nonlinear electromagnetic force model with control parameters is established,and the influence of control parameters on the electromagnetic force is discussed.Then,according to the dynamic characteristics of flywheel rotor,the nonlinear dynamic equation of four degree of freedom rotor considering gyroscopic effect is established by combining Newton mechanics with gyroscopic mechanics.Secondly,on the basis of the established dynamic model,the radial vibration characteristics of the four degree of freedom flywheel rotor supported by nonlinear electromagnetic force are analyzed according to the fourth-order ronko Kutta numerical integration method,and the mechanism of the influence of system parameters on the flywheel rotor vibration is discussed by means of Poincare mapping,phase diagram and time domain diagram.The multi-scale method is used to solve the approximate analytical solution of the nonlinear dynamic model of the flywheel rotor system with a single degree of freedom,and the nonlinear vibration mechanism is discussed.The influence of electromagnetic force support stiffness on the critical speed and vibration amplitude of the system is analyzed by using finite element method,and the influence of angular acceleration on the critical speed of the system is discussed.In addition,the gyroscopic moment is derived under the four degree of freedom motion equation,and the influence of gyroscopic effect on the critical speed of rotor is discussed.Finally,the 600 wh magnetic suspension flywheel energy storage prototype is debugged and dynamic tested,and the collected data are processed.The radial vibration characteristics of the upper and lower electromagnetic bearings at different speeds are analyzed by time domain diagram and frequency domain diagram.It is found that the vibration of the rotor is severe in the critical speed range,and the rotor system motion has centering effect.The experimental data are consistent with the theoretical analysis and simulation results.