Modeling And Analysis Of The Dynamics Of Moving Bearing Electromagnetic Bearing-rotor System

Active electromagnetic bearing(AMB)is a high-performance mechatronics bearing.Using controllable electromagnetic force to provide non-contact suspension support for the rotor system,the suspension result is similar to the traditional mechanical bearing,but the rotor system can achieve a much higher speed than the traditional mechanical bearing.In addition,AMB also has such advantages as zero friction loss,no need for lubrication,long service life,vibration control and so on.Therefore,AMB is widely used in aerospace,high speed rotation,high precision processing and high efficiency energy storage and other fields.In most studies,the electromagnetic bearing-rotor system is generally installed at the center of mass position of the carrier.However,in the actual process,the position of the rotor system on the carrier may change according to different requirements,and it is not installed at the position of the center of mass of the carrier.In most studies,the effect of the rotor system's installation position and axial direction on its dynamic characteristics is not discussed in detail.Therefore,it is significant to study the influence of rotor dynamic characteristics when the rotor position and axial direction change.This paper mainly analyzes the effect of the mounting position and axial direction of the electromagnetic bearing-rotor system on the dynamic characteristics of the system.Firstly,this paper summarizes the development of magnetic levitation technology and electromagnetic bearing modeling,analyzes in detail the components of active electromagnetic bearing-rotor system and the motion differential equation based on Newtonian mechanics,and briefly describes the working principle of the bearing system.Secondly,set up the ground fixed rectangular coordinate system,relative rectangular coordinate system,the vehicle auxiliary rectangular coordinate system and the rotor rectangular coordinate system and so on four coordinate system to describe the position of the rotor,based on Lagrange equation of the rotor system installed in any installation position of the mobile vehicle and general motion differential equations of axial direction,analyses the installation location parameters and axial direction is different to the influence of the rotor system dynamics characteristics.Mathematical models based on Newton mechanics and Lagrange equation were built on Matlab/Simulink.A hardware-in-the-loop real-time simulation platform with dSPACE system was built,and dSAPCE system and Simulink module in the system platform were introduced in detail.Finally,rotor suspension simulation experiments were carried out in models based on Newton mechanics and Lagrange equation,and the simulation results were compared and analyzed.In the model based on Lagrange equation,the simulation experiment of the rotor system on the moving carrier with different installation position and the same axial direction was carried out,as well as the simulation experiment of the rotor system with the same installation position and different axial direction.The effect of the rotor system's installation position and axial direction on the dynamic characteristics of the rotor system is analyzed.The suspension experiment of the rotor system under the static state of the carrier and the suspension experiment of the rotor system under the vibration state of the carrier were carried out on the semi-physical simulation platform.Based on Lagrange equation model,the suspension simulation experiment of rotor system is carried out in the static or vibration state of the carrier.The effect of the mounting position and axial direction of the active electromagnetic bearing-rotor system on the motion characteristics of the rotor is analyzed.