Position Sensorless Control Of Permanent Synchronous Motor Based On Model Reference Adaptive System

Permanent magnet synchronous motor has been widely used in servo system,numerical control machine,rail transit and other fields because of its many advantages.Compared with using position sensor to obtain the rotor position,using the sensorless technology is helpful to save the cost and improve the reliability of the system.The model reference adaptive method has been widely used because of its simple algorithm and high steady state accuracy.In this paper,the position sensorless vector control of PMSM based on model reference adaptive is studied.The main contents are as follows:Aiming at the non ideal factors in the actual application of control system,the system delay problem under two different current sampling and PWM updating modes is analyzed.A dead time compensation method for inverter with amplitude and phase compensation is studied.Two kinds of model reference adaptive rotor position estimation methods are studied,which are stator current model reference adaptive method and stator flux model reference adaptive method respectively.Based on Popov's super stability theory,under the condition that the global stability of the system is satisfied,by rational selection of the linear compensator matrix,the adaptive law of the model reference adaptive system with speed as the estimated variable is deduced in detail,so that the speed and rotor position of PMSM can be accurately estimated.The structure block diagram and the closed loop transfer function of the speed estimation error system are analyzed and established.By referring to the root locus analysis method,we study the changing trend of the characteristic root of the system when the PI parameter of the adaptive mechanism is changed,and analyze the influence of the PI parameters of the adaptive mechanism on the dynamic and static performance of the system,so as to provide a theoretical basis for the rational selection of the PI parameter.By comparing the closed-loop transfer function between two methods,it is found that the model reference adaptive rotor position estimation method based on stator current and stator flux based on the stator flux is completely consistent.According to the closed loop transfer function,the relationship between the PI parameters of the two methods is determined,which provides convenience for theselection of PI parameters.The simulation study and experimental comparison of the two model reference adaptive methods under different working conditions are carried out.At the same time,the system delay compensation and the dead time compensation effect of the inverter are verified.The results show that the estimated results of the two methods are basically the same,and have good estimation accuracy in the steady-state,dynamic process such asspeed change and torque mutation.