Research On Sensorless Control Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)has the advantages of light weight,small size,strong reliability,high control efficiency,and has been widely used in electric vehicles,aerospace and industrial production.Generally,the position information of the rotor is obtained by mechanical sensors,and the corresponding control system becomes larger and less reliable,but also needs regular maintenance,which leads to the increase of manpower and material resources.Aiming at the above problems,the sensorless control strategy of permanent magnet synchronous motor is studied in depth in this paper.Firstly,the research background and significance of the topic are expounded,the classification and common coordinate transformation of permanent magnet synchronous motor are introduced,and the mathematical model of permanent magnet synchronous motor in natural coordinate system and synchronous rotation coordinate system is established.The voltage space vector(SVPWM)strategy of permanent magnet synchronous motor is studied,the control method is selected,and the corresponding simulation model is established.Secondly,the basic principle of sliding mode control(SMO)is introduced,and the sensorless method of permanent magnet synchronous motor based on SMO is studied.In order to solve the chattering problem of sliding mode observer,an improved sliding mode observer based on the traditional sliding mode observer is proposed,which uses the continuous switch function at zero point and a new approach rate.The simulation models of sensorless PMSM control system with traditional sliding mode control and improved sliding mode control are established and the simulation and comparison experiments are carried out.The improved sliding mode observer can suppress chattering and enhance the robustness of the system.In order to solve the problems of low precision and slow dynamic response of conventional PI control,fuzzy PI control was proposed to optimize conventional PI,which reduced the chattering and response time of the system and further improved the dynamic and steady performance of the system.Then,the basic principle of model reference adaptive(MRAS)is discussed.The difference between the output of the adjustable model and the reference model is used to design the adaptive law,so as to identify the rotor speed and position of the motor.In order to solve the problem that the PI controller parameter adjustment is difficult in MRAS control system and the application speed range of a single PI value is limited,the BP algorithm is proposed to design adaptive law to construct the identification system.The simulation model of the position sensorless PMSM control system based on traditional model reference adaptive and improved model reference adaptive is established and the comparison test is carried out.The improved MRAS can improve the speed and tracking accuracy of motor parameter identification.Finally,the hardware circuit and software program of the sensorless control system of permanent magnet synchronous motor with main control chip TMS320F28335 as the core are designed.The experiment verifies the feasibility of the sensorless control strategy of PMSM based on SMO.