Research On Sensorless Control Of PMSM Used In Electric Vehicle Compressor

Permanent magnet synchronous motor(PMSM)has been widely used in more extensive aspects because of its advantages of low loss,high efficiency and simple structure.One of the most important aspects of the application is to drive electric vehicle air conditioning compressor.But the position and speed sensor of permanent-magnet motor cannot be installed in the electric automobile air compressor system.In order to overcome the limitations of sensor to control system application,this thesis proposes the method of sensorless control based on high frequency rotating voltage injection method and model reference adaptive for the electric automobile air conditioner compressor.Firstly,the mathematical model of PMSM is built and the basic principles of rotor field oriented vector control and voltage space vector pulse with modulation(SVPWM)are introduced in detail in this thesis,on this basis to build a permanent magnet synchronous motor based on SVPWM double closed-loop vector control system and the simulation is analyzed.Secondly,on the basis of vector control,the sensorless technique of PMSM is analyzed in detail in this paper.The thesis proposes the sensorless control system based on high frequency rotating voltage injection method to the PMSM with obvious salient structure and designs the speed observer based on butterworth filter and phase-locked loop technology.The basic principle of high frequency rotating voltage injection method is described.Then,the separation of injected high frequency current signals,the extraction of negative sequence current and rotor position information acquisition are analyzed in detail.Finally,a permanent magnet synchronous motor based on high frequency rotating voltage injection method is built and the simulation is analyzed.By the analysis of the experimental results,high frequency rotating voltage injection method can accurately estimate the rotor position and speed information,the system has a good stability and can be used in electric automobile air-conditioning compressor.Finally,due to unable to accurately extract the high frequency components in the high frequency injection method,the thesis proposes the method of sensorless control based on model reference adaptive to the PMSM with unobvious salient structure.The reference?model?and?adjustable model of the current are built,and the difference between the two model outputs is adjusted by the adaptive mechanism and the adaptive rate to adjust the parameters of the model in real time,so as to realize the parameter identification of the speed and position of the motor.The simulation and result analysis of the system shows that the new speed sensorless vecor control strategy of permanent magnet synchronous motor for electric vehicle based on model reference adaptive has a good effect on motor parameter identification and dynamic,static performance.