Study On Vector Control System Of PMSM Drives Based On MPC

Permanent magnet synchronous motor(PMSM)is widely used in industry because of its high precision,high efficiency and excellent performance.At the same time,PMSM system is a typical nonlinear system,while the traditional PI control method fails to achieve satisfactory performance in some specific cases,while the model predictive control(MPC)is a simple and easy to use,fast response and excellent control performance.In recent years,it has become a hot topic for domestic and foreign scholars.However,as MPC is a control method based on motor model,it is highly dependent on the accuracy of model parameters,and the mismatch between the predicted model and the actual model will directly lead to performance degradation.In order to reduce the influence of parametric mismatched PMSM model predictive control,this paper proposes a two vector based robust model predictive current control of PMSM.The work is as follows:1.In view of the problem that single vector MPCC can only output one switching state in a single control cycle,the basic principle of two vector MPCC is analyzed,and the selection method of the second voltage vector is improved to narrow the selection range of voltage vectors and reduce the algorithm complexity.The simulation model of single vector and two vector MPCC was established.2.Aiming at the problem that the model predictive current control of permanent magnet synchronous motor is sensitive to parameters,the errors of the dual vector model predictive current control under the condition of different parameter mismatch are analyzed from the two aspects of the predicted current value and the voltage vector action time,and the simulation model is built to analyze the errors caused by different parameter mismatch.3.Based on the idea of model-free control,the traditional ultra-local model is analyzed,and the current prediction model is reconstructed by using the improved ultra-local model designed,and the extended sliding mode observer is designed to observe the unknown disturbance term in the ultra-local prediction model,and its stability is proved by Lyapunov function.Aiming at the problem that chattering occurs near the slide plane of the traditional sliding mode observer,which leads to poor steady-state performance,fal function is introduced to replace the original sign function to suppress chattering phenomenon.The simulation model is built by MATLAB/Simulink software,and the algorithm is verified by hardware experiment platform.The simulation and experimental results show that,compared with the traditional two vector MPCC,the proposed method eliminates the errors of predicted current value and voltage vector action time caused by parameter mismatch,and improves the parameter robustness of PMSM system.