Research On Fast And Accurate Speed Control Method Of Permanent Magnet Synchronous Motor Based On Disturbance Observation

Permanent magnet synchronous motor(PMSM)is widely used in the field of electric vehicles because of its small size,high power density and high efficiency.In this paper,the permanent magnet synchronous motor is taken as the research object.In the shift synchronization stage,the drive motor completes the synchronization of the speed difference of the transmission input shaft through active speed regulation.In view of the slow response and poor robustness of the motor in the speed regulation mode of the drive motor in the shift synchronization stage of pure electric vehicles,through the combination of theoretical analysis,mathematical modeling,simulation and experimental verification,A model predictive control method of permanent magnet synchronous motor based on disturbance observation is studied to realize the fast and accurate speed regulation of the drive motor in the shift synchronization stage.The specific work of this paper mainly includes the following aspects:(1)Matched the parameters of the drive motor.According to the application scenario of permanent magnet synchronous motor for electric vehicle,the requirements of driving motor for electric vehicle were analyzed;Aiming at the dynamic parameters of a pure electric vehicle,the parameters of the driving motor were matched;The mathematical model of permanent magnet synchronous motor was established in different coordinate systems;The realization process of space vector pulse width modulation control technology was described in detail.(2)The current loop adopted deadbeat current predictive control.The basic principle of deadbeat current predictive control was described,and the stability was analyzed;The current loop in the traditional PI vector control was replaced by deadbeat current predictive control,which solved the shortcomings of PI control and had the advantages of rapid dynamic response and no parameter setting.The results showed that when the deadbeat current predictive control was adopted,the response speed of the motor under no-load state was accelerated by 23% compared with the PI control,which effectively improved the response speed of the current.(3)An improved deadbeat current predictive control based on second-order reaching law was studied.Aiming at the problems of current steady-state error caused by control delay and motor parameter mismatch when PMSM adopted deadbeat current predictive control,an improved deadbeat current predictive control method based on second-order reaching law was proposed to realize the accurate control of current loop.By introducing the disturbance caused by the mismatch of model parameters into the voltage equation of the motor,a sliding mode disturbance observer was constructed to observe the system disturbance;The predictive current in the sliding mode observer was used to replace the sampling current to solve the problem of control delay;Aiming at the chattering problem of sliding mode observer,a second-order reaching law based on sgn was designed,and the stability of the controller was proved;The observed and estimated system disturbance was combined with deadbeat current predictive control through feedforward compensation,so as to improve the parameter robustness of deadbeat current control.The results showed that when the motor parameters did not match,the proposed control method could effectively observe the system disturbance,make the steady-state error of dq axis current less than 0.05 A,and effectively improve the parameter robustness of the motor.(4)A model speed predictive control based on internal model disturbance observer was studied.Aiming at the problem of poor anti disturbance ability and robustness when PI control was used in the speed loop,a model speed predictive control was proposed;The internal model disturbance observer was used to observe the change of external load disturbance and feed forward compensation to the speed loop,so as to improve the ability of the motor system to resist the change of external load and improve the robustness of the system.The results showed that compared with deadbeat current control,the dynamic response speed of the motor was increased by 27%,and the speed fluctuation was reduced by 40% after sudden load torque,which effectively improved the anti-interference ability of the motor and speeded up the response speed of the motor..(5)The model predictive control of permanent magnet synchronous motor based on disturbance observation was verified by experiments.The speed regulation control test platform of permanent magnet synchronous motor was built by using RTU-BOX real-time digital control system.The test results showed that the model predictive control algorithm of permanent magnet synchronous motor based on disturbance observation adopted in this paper had fast response and strong resistance to external interference.