MPC Based Full-speed Domain Control Strategy Of Interior Permanent Magnet Synchronous Motor

Energy crisis and climate warming have become increasingly prominent,making new energy vehicles popularized in the world.The interior permanent magnet synchronous motor(IPMSM)has an absolute dominant position in the motor of new energy vehicles due to its high efficiency,simple structure,high power density and stronger load capacity of the surface PMSM.Model predictive control(MPC),as an advanced control strategy,is increasingly used in industry due to its good dynamic performance.Electric vehicles require that the motor must be able to follow the torque required for driving,and respond quickly to the complex conditions in the driving process at the same time.Therefore,this paper takes the IPMSM as the research object,and the following research is carried out on the model predictive control method under the control of electric vehicle full-speed domain:Firstly,the research status of PMSM control strategy and model predictive control is summarized and analyzed,and the common MPC strategies of PMSM control systems such as continuous control set and finite control set are analyzed and compared.The mathematical model of three-phase permanent magnet synchronous motor is established,and the mathematical model of PMSM in d-q coordinate system is deduced.The basic principle of model predictive control is detailed,and the establishment method and discretization method of prediction model are given.On the basis of the mathematical model of the motor in the rotating coordinate system,the linearization of the model is carried out.This lays the foundation for the theoretical model of the full-speed domain model predictive control.Secondly,the full-speed domain control strategy of permanent magnet synchronous motor is studied.The mathematical derivation of MTPA control and field weakening control theory of permanent magnet synchronous motor is carried out.For its mathematical and physical meanings,it is rewritten into a mathematical model that can be used in MATLAB.A new current calculation method in field-weakening conditions is proposed and used to obtain the current in d axis and q axis under weak magnetic control.The simulation model of IPMSM traditional double closed-loop control with PI regulator is built to verify the reliability of the above current control method in full-time domain control.Then,the full speed domain control of PMSM under model predictive control is studied.Based on the cascaded closed-loop control of PMSM,the model predictive speed controller and current controller are designed.Due to the complex structure of the cascaded system and the limited dynamic response performance,a predictive control strategy for non-cascading PMSM models is proposed.The control of current and speed is realized in one controller,and the parameters affecting the stability of model prediction control are qualitatively and quantitatively analyzed.Combining the model predictive control with the full-speed domain control strategy,the dynamic response capacity and load capacity of PMSM under full speed domain operation with model predictive control and traditional PI control are compared and analyzed.The simulation shows that compared with PI control,the model predictive control has faster response speed and better dynamic performance when loading and unloading.Compared with cascaded MPC,the non-cascading MPC has lower computational complexity and better control performance.Finally,an experimental platform of PMSM drive control based on model predictive control is built,and the software flow is designed and programmed according to the algorithm studied.The experiment verifies the correctness and effectiveness of the simulation,which indicates that the PMSM model predictive control can obtain excellent dynamic performance and is suitable for the complex working conditions of electric vehicles.