Research On Position Sensorless System Of Permanent Magnet Synchronous Motor

Due to its high efficiency,high power,wide speed regulation,stable operation and many other characteristics,permanent magnet synchronous motor(PMSM)is widely used in various fields.The traditional PMSM feeds the acquired information back to the system through mechanical sensors,which not only increases the cost and volume of the system,but also deteriorates the stability of the system.Therefore,PMSM without position sensor has become a hot topic of current research.In this paper,the application of position sensorless sensors in different speeds of PMSM is studied in depth.Firstly,this thesis introduces the mathematical model of PMSM in three coordinate systems,and establishes the PMSM system simulation based on SVPWM principle and vector control strategy.In the low-speed section operation,for the pulse-induced high-frequency voltage injection method,the increase of impedance affects the shortcomings of the system's accuracy of rotor speed and position estimation.This thesis proposes a pulse-induced high-frequency current injection method and uses high-frequency response straight.The second harmonic component of the shaft voltage is used to optimize the determination of the positive pole.Secondly,This thesis uses the synovial membrane system to control the operation of the motor at medium and high speeds.Briefly describes the principle and conditions of the synovial membrane control method.On this basis,this thesis describes the chattering problem that can not be eliminated in the traditional synovial membrane control method.Designed a new synovial observer to improve the impact of buffeting on the motor system:Use a continuous hyperbolic tangent function instead of a traditional switching function,In order to reduce the influence of disturbance,and increase the filtering mechanism of the latter stage,the core is based on the secondary filter compensation technology of variable cutoff frequency.On this basis,the arctangent function is replaced by a phase-locked loop to estimate rotor position and speed information.Finally,this thesis combines the low-frequency operation high-frequency injection method and the mid-high-speed operation slip film control method to normalize and weight the low-speed and medium-high-speed position errors.and builds a composite control method that allows the motor to operate at full speed.Figure [70] table [5] reference [66]...