Research On Active Disturbance Rejection Control Of PML SM

Permanent Magnet Linear Synchronous Motor(PMLSM)can be used for direct drive technology without intermediate buffer mechanism.Internal parameter perturbations caused by disturbances in external environment and changes in motor operating conditions will directly affect PMLSM.Which affects the immunity and control accuracy of PMLSM.For machining industries such as CNC machine tools that require high control accuracy,it is especially important to improve the anti-disturbance capability of PMLSM.Unlike the rotating electric machine,the PMLSM has a structural asymmetry due to the breaking of the iron core,and its internal parameters change with the operating conditions of the PMLSM,which makes the PMLSM nonlinearity and coupling stronger.The traditional PMLSM control system often ignores the change of inductance.It will inevitably deviate from the actual working conditions.In order to obtain higher control precision,an accurate mathematical model of PMLSM the variable inductances are established in this thesis,the three-phase asymmetric nonlinear inductances are measured by experiment.Based on the matrix equation,the PMLSM nonlinear model is constructed and the PI control system is built.The simulation results show that compared with the PI control system based on the inductive PMLSM mathematical model,the variable inductance control system has the characteristics of higher regulation and less disturbance suppression.And the new model is closer to the actual model of PMLSM in theoretical analysis,which is conducive to achieve higher quality control accuracy.In this thesis,the variable inductance PMLSM mathematical model is introduced into the ADRC technology.Aiming at the problem of high sensitivity to disturbance of permanent magnet synchronous linear motors(PMLSM)is used in the high precision numerically controlled(NC)machines servo system affecting the stability and control accuracy of the system,an improved active disturbance rejection control(ADRC)strategy for permanent magnet linear synchronous motor(PMLSM)is proposed.A new non-linear function is introduced into the extended state observer to overcome the rough of non-linear function in extended state observer of conventional ADRC.By using the extended state observer of improved ADRC,the total disturbance of the system is estimated for real-time dynamic compensation.The proportional differentiator is used to replace the nonlinear state error feedback(NLSEF),and the difficulty of system parameter adjustment is reduced.The Matlab is used to simulate PMLSM speed control system based on the improved ADRC control strategy,and the effects of system's no-load start response characteristics and suddenly-applied load disturbances on the steady-state performance of the system were tested.The research results indicate that the improved ADRC strategy has better load disturbance rejection and smaller overshoot than the traditional ADRC control strategy.It can make the system has a good control accuracy.