Analysis Of Influence Of Unbalanced Magnetic Tension On Critical Speed Of Rotor System In Energy Storage Flywheel Motor

Modern flywheel energy storage uses high-speed rotating flywheel to store energy.It is a new energy storage technology,which uses the external wind to drive the motor to run,so as to realize the acceleration of energy storage and the deceleration of power generation to release energy.Flywheel energy storage unit module is a typical electromechanical high-tech integrated system,involving many disciplines or different professional fields such as materials,machinery,electronics and control.In this paper,the differential equation of four degrees of freedom motion of rotor system is established by using Newton classical mechanics principle and moment of momentum theorem,and the influence of unbalanced magnetic tension between stator and rotor on the critical speed of rotor system is analyzed The transfer matrix method is used to analyze the influence of unbalanced magnetic tension on the mode shape at critical speed;The critical speed of rotor system is solved by finite element method,and the influence of unbalanced magnetic pull on the critical speed and vibration mode of rotor system is simulated.Firstly,according to Maxwell stress tensor method,the unbalanced magnetic tension model between stator and rotor of magnetic levitation flywheel motor is established,and the unbalanced magnetic tension expression is obtained.Then,the stiffness of unbalanced magnetic pull along the minimum air gap direction and the components of unbalanced magnetic pull stiffness in different coordinate axes are obtained by deriving the unbalanced magnetic pull from the air gap length.Secondly,by applying Newton’s classical mechanics principle and moment of momentum theorem,the differential equation of four degrees of freedom in the process of rotor system acceleration is established.Runge-Kutta method is used to solve the differential equation of rotor system motion.The vibration characteristics of the transfer subsystem and the influence of unbalanced magnetic pull on the critical speed of rotor system are analyzed by time domain diagram,frequency domain diagram,axis trajectory diagram and Campbell diagram.Thirdly,the transfer matrix model of magnetic levitation flywheel rotor system is established by using the transfer matrix method.The influence of unbalanced magnetic tension between stator and rotor on critical speed and amplitude at critical speed is analyzed.Using the finite element principle and ANSYS software,the vibration mode diagram and Campbell diagram of rotor system are obtained.By analyzing the vibration mode diagram and Campbell diagram,the influence of unbalanced magnetic tension on the vibration mode and critical speed of rotor system is discussed.Finally,energy storage experimental equipment is installed in the laboratory.Debugging the equipment and collecting experimental data,filtering the collected experimental data,obtaining the vibration time domain diagram,vibration frequency domain diagram and axis track diagram of the rotor system,analyzing the influence of unbalanced magnetic tension between the stator and rotor of the motor on the vibration characteristics of the rotor system at critical speed during the actual rotor movement,and verifying the correctness of the calculation and simulation results.