Research On Position Sensorless Vector Control For Permanent Magnet Synchronous Motor Over Wide Speed Range

The permanent magnet synchronous motor(PMSM)has the advantages of high performance,high reliability and high power density.Owing to the progress in the permanent magnet materials,power electronics,fast digital signal processors,and modern control technologies,permanent magnet synchronous motors have become more widespread in industrial applications,such as in electric vehicles,robotics,rail transportation,aeronautics,and aerospace domains.In order to overcome the disadvantages of traditional position sensor,sensorless control has become a hot research direction in the field of permanent magnet synchronous motor control.In this paper,the sensorless control strategy of permanent magnet synchronous motor is studied over wide speed range.The main research work of the thesis includes the following.The dynamic mathematical model of permanent magnet synchronous motor under three phase static ABC coordinate system is established through the analysis of physical principle,and the dynamic mathematical model of permanent magnet synchronous motor in two phase stationary coordinate system and two phase synchronous rotating dq coordinate system is obtained by coordinate transformation.Some important characteristics of the motor are obtained by mathematical model analysis.The working principle and PWM modulation technology of two level voltage source inverter are analyzed.Several commonly used vector control strategies for permanent magnet synchronous motor are introduced.In this paper,i_d(28)0 control strategy is used to construct a complete vector control system for permanent magnet synchronous motor,and a simulation model is built.The vector control with a position sensor is realized and its control performance is analyzed.The coordinate system commonly used in sensorless control strategy is defined,and the mathematical model of PMSM excited by high frequency signal is deduced.The principle of two sinusoidal high frequency voltage signal injection methods is analyzed,and their advantages and disadvantages are summarized.By using the method of square wave high frequency voltage signal injection,the frequency of injection signal is raised to the frequency of PWM switch,and the signal processing method without filters is proposed.Thus the sensorless control performance is improved.Combined with the current response of square wave voltage injection saturation,a method for checking the polarity of rotor flux is presented.High performance sensorless control of PMSM is realized in zero and low speed domain.In the two phase synchronous rotating dq coordinate system,the new induction electromotive force(EMF)is defined.A sliding mode observer is designed based on the error between the given current and the feedback current.The estimated value of the rotor position and velocity is obtained by sending the observed values of the newly defined d axis induction EMF into the phase locked loop.Using the characteristics of the extended state observer in the ADRC,the input of the phase locked loop is constructed,and a sensorless control strategy is proposed,which inherits the advantages of active disturbance rejection control.By introducing the weighted algorithm,a hybrid sensorless control strategy for PMSM is presented,which is suitable for full speed range.The hardware and software design of PMSM towing platform is completed,and debugging is completed to ensure that the experimental platform works safely and normally.Experiments verify the effectiveness of the wide speed range sensorless control strategy.