Unbalance Analysis And Compensation Of Maglev High-speed Permanent Magnet Motor With Rotor Eccentricity

With the advantages of high speed,high power density and good speed regulation performance,maglev high-speed permanent magnet motor has been increasingly used in high-speed rotating machinery.However,due to material imbalance,machining and assembly errors,the rotor system inevitably has eccentric umbalance,which leads to vibration and reduces system performance and stability.This paper started with the unbalanced magnetic pull(UMP)of permanent magnet motors,and focused on the unbalance analysis and compensation of high-speed maglev motor rotor system.First,taking two-pole slotless permanent magnet motor with rotor eccentricity as research object,the fully analytical model of its no-load magnetic field was established based on the subdomain and perturbation method.The correctness of the analytical model was verified by finite element analysis,and the influence of slotting and armature effects on the motor magnetic field was further studied.Secondly,the stiffness coefficient was introduced to describe the UMP,and the dynamic model a4 DOF magnetically suspended rigid rotor with UMP was established.The effects of the UMP stiffness and its arm coefficient,the controller parameters,and the bias current on the stability and dynamic response of the rotor system were analyzed.For the unbalance vibration compensation of the rotor,a compensation algorithm based on singlephase coordinate transformation was proposed,which avoided the interference caused by the umbalance of magnetic bearing’s 2 DOF.Stability of the closed-loop system after embedding compensation algorithm was analyzed,and corresponding stability conditions were given.Feasibility of the algorithm was proved by simulation,and the influence of different algorithm parameters on the compensation performance was discussed.The preliminary selection basis of the algorithm parameters was given.For the unbalance force compensation of the rotor,a speed adaptive compensation algorithm based on SOGI-FLL was proposed,and clear parameter design principles were given.The compensation of UMP was additionally considered.Imitating phase-shifted notch filter,the phase-shifted SOGI-FLL was further designed to expand the application of the algorithm in low speed range.Stability of the closed-loop system under zero current and zero force compensation was analyzed,and the corresponding stability conditions were given.Feasibility of the algorithm was proved by simulation,and the effects of noise and different algorithm parameters on the speed estimation and compensation control performance were further studied.Finally,an experiment platform of magnetically suspended rotor based on d SPACE was built,and two compensation control algorithms were verified by experiments.