Analysis And Control For An Active Magnetic Bearing-Rigid Flywheel Rotor System

Active magnetic bearing(AMB)with suitable for high speed running,no mechanical contact.no lubrication and adapt to the complex environment and other characteristics,has been as such as high speed motors and high-speed flywheel energy storage system,and many other industrial situation of main bearing unit.This paper aimed at the analysis and control for an active magnetic bearing-rigid rotor flywheel system.As for the modeling of the radial 4-degree-of-freedom(DOF)AMB-rigid flywheel rotor system,it begins with the mathematical model of the unbalance Jeffcott rotor,and then extended to the 4 DOF AMB-rigid flywheel rotor system with rotor imbalance.Two kinds of modeling method are presented:One regards the the rotor imbalance as an extra mass(called the unbalance mass)near at the mass center of the balanced rotor and the unbalance mass is too small to affect the position of mass center of the unbalanced rotor.The other regards the rotor imbalance as teo extra mass located at the rotor in two bearing planes.Then,the dynamics equations of the rotor in bearing coordinate system are deduced both with these to kinds of modeling.At last,the consistency of these two kinds of modeling methods is proofed.As for the stability control of the 4 DOF AMB-rigid flywheel rotor system,in order to give the basis for selecting controller’s parameters,the motion characteristics of the Jeffcott rotor with PD control is first dicussed which focus on the influence on rotor’s motion of PD parameters.Then,decentralized PID control and linear state feedback control are introduced and the effectiviness is confirmed in the simulation.As for the displacement control of unbalance vibration,a variable step size polygon iterative seeking algorithm is proposed to identify the rotor imbalance.An unbalance compensator is designed base on this algorithm to control the displacement of the rotor caused by the unbalance vibration.As for the cotrol of the unbalance vibration force,two methods are proposed:zero-current control and zero-force control,the iterative seeking algorithm is applied to identify the synchronic component of the rotor displacement,the zero-current controller and the zero-force controller are designed bases on this algorithm to control the unbalance vibration force.As for the control of the multi-frequency disturbing force caused by sensor runout,the iterative seeking algorithm is applied to identify the multi-frequency component of the rotor displacement,the multi-frequency force controller is designed bases on this algorithm to control the multi-frequency disturbing force.At last,the AMB-rigid flywheel rotor experiment platform based on dSPACE 1103 control panel as the core controller is introduced.Then the rotor is stably levitated by the control method propose in this paper and the effectiviness of the unbalance compensator is confirmed.