| The permanent magnet synchronous motor has been widely applied in varies fields due to it’s a serious of advantages.However,since it does not have the ability of self-starting,it must have a matching driver to run normally.Besides,it needs the rotor position signal when running,wherein,the conventional position sensor does not have versatility,and it will increase the cost of the system and the failure point.Thus,in recent years,the speed sensorless control technology of permanent magnet synchronous motor(PMSM)has become a research hotspot in the field of motor drive,and plenty of scholars have put forward various control strategies.In this thesis,from the system point of view,according to different loads,different combined control strategies are designed,so that the controller can realize sensor-less control of permanent magnet synchronous motor in the full speed range.The specific research contents are as follows:(1)This thesis summarizes the common control methods of permanent magnet synchronous motor,introduces several sensorless control methods of different strategies,and determines the control strategy used to solve the problem by comparison and analysis.(2)This thesis introduces the basic structure and characteristics of permanent magnet synchronous motor(PMSM),gives its mathematical model in different coordinate systems,determines the vector control method at id=0,puts forward a simple and practical method for parameter identification of off-line motor,and expounds the advantages and necessity of standardization and digital calibration of the control system.Eventually,the design rule of the PI parameter of the current loop in vector control is derived.(3)In this thesis,the realization principle of the Lumberg observer method based on the fundamental wave back EMF model and the pulse high frequency voltage injection method based on the fundamental wave back EMF model for the middle and high speed bands are studied,and the design methods of the two methods are mastered.Meanwhile,the simulation model of sensorless vector control based on the pulse high frequency voltage injection is built.The feasibility of the design method is verified by simulation results.(4)According to the characteristics of fan-pump load,a starting strategy of speed open-loop-current closed-loop control with current-frequency ratio in low speed section is proposed.Furthermore,the rotor position is estimated by Lumberg observer in middle and high speed section,and the vector control method of speed-current double closed-loop is switched.Moreover,the starting process of current-frequency ratio speed open-loop and current closed-loop is studied,and the conditions of stable starting and acceleration are given.A state switching strategy of open-loop algorithm and closed-loop algorithm is proposed to ensure that the torque does not change abruptly during the switching process.A method of rotor stalling detection based on back EMF calibration is proposed,which detects the stalling state of rotor during buffeting.Eventually.(5)A permanent magnet synchronous motor(PMSM)controller for fan-pump loads is developed to verify the feasibility of the control strategy,and the corresponding software control flow chart is given.Additionally,the experimental results of the controller during starting,switching and rated load operation are analyzed,and the practicability and reliability of the control scheme are verified.At the end of this thesis,the research contents and the results of the study are summarized,and the future research improvement direction of the controller performance is also discussed. |
