Research On Restart Strategy Of Permanent Magnet Synchronous Motor Position Sensorless Control System In Wide Speed Range

Permanent Magnet Synchronous Motor(PMSM)benefits from the advantages of high power density,high conversion efficiency,small size,fast response speed,and small torque ripple,and has attracted much attention in various fields of industry.The position sensorless control technology of PMSM can eliminate mechanical position sensors,reduce costs,and improve reliability.This technology has developed rapidly in recent years and has gradually entered the field of industrial applications.However,position sensorless control technology also brings new problems,which makes it more difficult for PMSM to restart with speed.Restart with speed means to start the motor when the motor driver turns off the output and the motor rotor speed is not zero.Because the output of the driver is closed and there is a back electromotive force in the stator windings of the motor that is proportional to the rotor speed,the traditional position sensorless control method cannot estimate the rotor position and speed of the PMSM under this condition.In this case,if the motor is started directly,it will have a big impact or even fail to start.To realize the restart of PMSM senseless control system,it is necessary to obtain the rotor position and speed information through a ce rtain method.On the other hand,the flux weakening control technology can broaden the speed range of permanent magnet synchronous motors and is widely used in PMSM drive control.However,there are few related researches on the restart method in the f lux weakening speed range.The focus of this paper is to analyze the key issues of PMSM restart in the flux weakening speed range,and propose a restart method in the PMSM flux weakening speed range,and combine the zero-voltage vector injection method to realize the wide-speed restart of the PMSM position sensorless control system.This article first introduces the mathematical model and vector control principle of PMSM.Based on vector control,the sensorless control based on sliding mode observer and the field weakening control based on voltage closed-loop feedback are implemented and verified on the Matlab/Simulink platform.Then the paper analyzes the zero-voltage vector injection method restart control principle,selects the two zero-voltage vector injection method as an example to analyze the error of the zero-voltage vector injection method.According to the error analysis results,the basis for selecting the width and interval of the zero voltage vector is introduced.The restart of the PMSM constant torque speed control zone based on the zero voltage vector injection method has been realized.After that,the paper analyzes the key points of restarting in the flux weakening speed control zone,and proposes an improved main circuit structure to avoid the damage of the high back electromotive force of the PMSM to the drive system in the field weakening speed control zone.Based on the improved main circuit structure and the principle of the zero-voltage vector injection method,this paper proposes an improved zero-voltage vector injection method based on short-circuit current reconstruction,which realizes the application of the zero-voltage vector injection method in the field weakening speed range.At the same time,a new current feature extraction method is proposed,which estimates the position and speed of the PMSM by identifying the current features in the uncontrolled rectification state,and realizes the restart of the PMSM field weakening speed regulation zone.Finally,combining the above methods,propose a restart scheme for the wide speed range of PMSM,design an experimental platform based on the DSP28335 processor,and verify the above contents experimentally.