Research On The Speed Control Of Permanent Magnet Synchronous Motor By Nonlinear Internal Model Design

Due to high power density,high efficiency and simple structure,permanent magnet synchronous motor(PMSM)has been widely used in various industrial applications such as electric vehicle,high-speed train traction,and wind power generation.PMSM has played a dominant role in AC motor speed regulation.PMSM is a complicated multi-input,multi-output nonlinear system.In real application,PMSM is susceptible to uncertainties such as internal system parameter perturbation and external load torque disturbance.Traditional control methods of PMSM have some limitations in dealing with complicated disturbance rejection problem.Nevertheless,the nonlinear output regulation theory can achieve multiple goals including accurate tracking of reference trajectory,disturbance rejection,and parameter robustness.Therefore,it is very important to study the control problem of PMSM by nonlinear output regulation theory.This thesis mainly studies the speed tracking and non-harmonic disturbance rejection problem of PMSM.The main research work is as follows:(1)This thesis studies the local speed tracking and non-harmonic disturbance rejection problem of PMSM.This problem can be formulated as a robust output regulation problem of multivariable nonlinear system.This thesis proposes a specific robust output feedback control law based on nonlinear internal model design,which can not only achieve accurate speed tracking,but also reject non-harmonic load torque disturbance.In addition,in order to achieve better motor parameter robustness,this thesis proposes an improved feedback control law.Simulation results demonstrate the effectiveness of the proposed control law.(2)This thesis studies the speed tracking and non-harmonic disturbance rejection problem of PMSM with wide speed range.This problem can be formulated as a robust output regulation problem of multivariable nonlinear system.By combining the advantages of classical double-loop control and nonlinear internal model control,this thesis proposes a two-step nonlinear controller design.First,double-loop control is used to adjust the states of the system to the neighborhood of the steady-state value,and then nonlinear internal model control is used to achieve accurate speed tracking.Simulation results demonstrate the effectiveness of the proposed control scheme.