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

Permanent magnet synchronous motor(PMSM)has the advantages of small size,light weight,simple structure,wide speed range and high power density.It has been widely applied in many fields,such as agriculture,industry,military,aerospace.The sensorless vector control technology has become a hotspot in the world because of its low cost,high precision of control and high reliability of the system,good speed performance and strong robustness.The sensorless vector control technology divide speed into three range:zero speed,low-speed and high-speed,the zero speed is the main initial position for detecting the rotor speed,low-speed is generally taken to extract the rotor position through the injection method,middle-and high speed is generally taken to observe the rotor position of motor through the back EMF Detection.In this paper,we study the high frequency voltage signal injection method of low speed for salient pole permanent magnet synchronous motor.First,the significance of the research is described in the introduction part of this article.Based on the analysis of the reasons that the injection method can effectively estimate the rotor information,IPMSM(Inner-mounted Permanent Magnet Synchronous Machine,IPMSM)is presented as the research object.Then,the paper discusses the present domestic and foreign developmental situation of the injection method in sensorless technology at zero speed and low speed range,and put forward method studied in this paper of using injection method for fluctuating high frequency voltage signal;and coordinate system on the coordinate transformation theorya is deduced and a simple mathematical model is deduced of PMSM in rotating coordinate system;After a simple description of the vector control theory,the paper expounds several common methods of vector control and compares the characteristics of various control strategies.Secondly,a new method based on the improved observer is designed to estimate the rotor position and speed information in the low speed.The first is to establish the mathematical model of high frequency permanent magnet synchronous motor,and then on the basis in mathematical model the cosine high frequency voltage signal was injected in estimating direct axisthe coordinate system,then describes the signal processing of two order Butterworth filter process,we design an improved observer to extract the rotor position and speed information and a new angle error of the program was analyzed,based on Matlab/simulink,built the simulation validation,the simulation results show that this method is feasible.Finally,on the basis of the simulation,this paper uses TI's TMS320F2808 as the main chip of the control board,and designs the sensorless vector control system of permanent magnet synchronous motor(PMSM).The static and dynamic performance of the system is tested on the permanent magnet synchronous motor.The experimental results show that the improved rotor position detection method based on the high frequency pulse injection method can meet the performance requirements of the system and has high accuracy.