Design Of Speed Sensorless Vector Control System For Permanent Magnet Synchronous Motor

Compared with other types of motors,Permanent magnet synchronous motor(Permanent-magnet synchronous motor,PMSM)has small size,high power factor,high torque density and high efficiency.Due to these outstanding advantages,PMSM has a wide range of applications.The high-performance PMSM speed control system is relatively complicated.The widely used vector control(Field-oriented control,FOC)technology can achieve high-performance control of PMSM.However,in order to achieve high-performance control,FOC control technology needs to know the motor rotor position and motor rotation in real time.Complete the speed control closed loop and coordinate transformation,the traditional PMSM sensored control technology mainly uses the mechanical position sensor to detect the rotor position and calculate the rotor speed.However,the sensored control technology has some shortcomings,such as increased costs,the sensor m ay have installation errors during the installation process,the position sensor is relatively sensitive to the environment,and cannot be used in harsh environments.In response to the various adverse effects of position sensors,in order to improve this situation,a sensorless control technology is applied,which mainly uses some parameters of the motor itself to estimate the rotor position and speed.The sensorless control technology can make up for the disadvantages caused by the sensored control,further reduce the size of the motor and reduce the rotational inertia,save costs,control system performance is not affected by the environment,and high reliability.This paper studies the sensorless control technology of surface-mount permanent magnet synchronous motor,which is generally divided into two categories: middle and high speed area and low speed area.When the motor speed range is in the middle and high speed area,the sensorless control technology based on sliding mode observer(Sliding mode observer,SMO)is used;when the motor speed range is in the low speed area,the sensorless control technology based on pulse high frequency voltage signal injection is used;Finally a compound control method is adopted,and the two sensorless control technologies are combined.The system can use the advantages of each method to achieve a smooth transition between the two algorithms.Finally,the simulation of MATLAB / Simulink is used to verify the correctness and reasonableness of the algorithm in this paper.This article first analyzes the high-performance PMSM vector control system.The main contents are: the basic structure of PMSM and its classification according to the installation position of the rotor permanent magnet,and the PMSM mathematical model.Then the principle and implementation method of FOC technology are analyzed in detail.PMSM is used in different occasions and lists several different vector control methods.Next,when the motor speed is in the middle and high speed area,the SMO sensorless control technology is used.To solve some pr oblems of the traditional SMO,some improvements are made.A new SMO is applied by using the S-type function to instead of switching functions,the system jitter can be significantly reduced.In view of the shortcomings of high harmonic content and phase delay in the traditional extraction of information,this paper constructs a back-EMF observer to extract back-EMF signals,and then estimates the rotor position and speed.This method eliminates the need for low-pass filtering,can significantly reduce the harmonic content in the extracted information and greatly reduce the phase delay time.Finally,in order to verify the rationality of the proposed method,build a simulation model in the MATLAB / Simulink environment.By analyzing the simulation results,the improved SMO proposed in this paper can significantly reduce the jitter of the system and improve the accuracy of the estimation.Then it analyzes the sensorless control technology based on pulsed high frequency voltage signal injection when the PMSM speed is in the low speed region.The main research content is the basic principle and implementation method of the high frequency injection method.The rotor position is got by the speed integrated.The use of a sensorless vector control technology based on the composite control of the weighted hysteresis switching algorithm ensures that the motor has high accuracy in estimating the rotor position and speed in the full speed range.The two control algorithms are combined to play their respective advantages,forming a composite control scheme,and using weighted hysteresis switching algorithm to smoothly transition two algorithms.and verified and analyzed through simulation.