Research On High Performance Control Strategies Of Permanent Magnet Synchronous Motor Speed Control System

Permanent magnet synchronous motor(PMSM)has been widely used in AC speed regulating system with the advantages of simple structure,little loss,high efficiency,high power density and reliable operation and so on.In recent years,the research on the control strategy of PMSM speed control system has become a research focus.In order to achieve high-performance control,this thesis took PMSM as the research object and analyzed the control strategy of current control loop and speed control loop.First,the structure,mathematical model and vector control principle of PMSM is introduced.Based on the electromagnetic theory,different vector control strategies are analyzed.Considering the different speed-torque characteristics,the id=0 strategy was adopted in this thesis.Due to dq-axis current coupling,the traditional PI control system has the problem of poor dynamic characteristics.Using voltage feedforward decoupling control can compensate the coupling terms,which can solve this problem.Second,the current control loop with traditional deadbeat control is designed,which can reduce the current harmonic content.Based on the characteristics of the traditional deadbeat control system,a novel deadbeat current controller is designed to reduce the sensitivity of the system.FCS-MPC can achieve the aims of single-objective and multi-objective control,suitable for high performance transmission system.The current loop is designed based on FCS-MPC and the optimizing mechanization and the possible current error of MPC strategy are analyzed.In order to solve the problem of large computation in FCS-MPC,an improved MPC based on fast vector selection is proposed in this thesis.Then,the speed control loop is designed with sliding mode reaching law,the speed dynamic characteristics and disturbances rejection were better than the conventional PI controller.Analyze the simple constant speed reaching law,point out the relationship between the approach speed and the sliding mode buffeting level,and design sliding mode controller based on constant speed reaching law.Compared with the constant speed reaching law,the power reaching law has small chattering with slow approach speed.In order to improve the power reaching law,the fast power reaching law is proposed.The novel sliding mode reaching law can not only suppress the chartering but also promote the convergence speed of the sliding-mode surface.The PMSM sliding-mode speed control system is built using proposed reaching law,and then the sliding-mode speed controller is designed.Last,based on the resource of laboratory,an AC-DC-AC hardware platform of permanent magnet synchronous motor(PMSM)speed control system is built.Using this platform,the vector control experiments based on voltage feedforward decoupling and predictive control experiments and sliding mode control experiments of PMSM are completed.The experimental results verified the feasibility and effectiveness of proposed control strategy.