Sensorless Control Of Permanent Magnet Linear Synchronous Motor In Full Speed Range

Permanent Magnet Linear Synchronous Motor(PMSLM)has been widely used in industrial control,machine tools,aerospaces and other fields because of its high speed,high acceleration,high efficiency,fast response,large stroke and no intermediate transmission links.Usually,control system of PMSLMs need hardware sensors to get the speed and position information of motors for feedback and forming a closed-loop system.But hardware sensors’ usage will increase the cost,reduce the reliability and limit the application of the system.Therefore,it is urgent to propose an efficient PMSLM sensorless control method in full speed domain.The aim of this thesis is to design sensorless control method in full speed domain for PMSLM.Based on the analysis of the existing methods,a PMSLM sensorless control system in full speed domain is designed by combining AEKF pulse vibration high frequency current injection method and the adaptive gain sliding mode observer.The main works are summarized as follows:1.A PMSLM mathematical model with dynamic inductance matrix is established by analyzing the special end effect of linear motors.Based on this model,Matlab/Simulink platform is used to build a simulation system,which can be used in the subsequent sensorless control simulations.2.A pulse vibration high frequency current injection method based on AEKF is proposed by analyzing the influences of the stator resistance’s change and the high frequency response signals’ extraction on the position estimation of the pulse vibration high frequency current injection method.This method can identify motor’s electrical resistance in real time while estimating the speed and position of the motor.Compared with the traditional method,the structure of the proposed method is simple and the anti-jamming ability of the sensorless position estimation module to environmental noise and measurement noise is improved,and the position estimation error is reduced.3.A adaptive SMO is proposed to alleviate the problem that traditional SMO with constant gain may increase of the chattering and reduce the estimation precision under the changing operation conditions.By the proposed adaptive-gain algorithm,the gain can dynamically adapt to a changing operation condition to weakening sliding mode chattering and improving the control precision.4.A switching mechanism based on hysteresis switching method is designed,by which the position estimation method in low speed domain,(pulse vibration highfrequency injection method based on AEKF)and the high speed domain position estimation method(adaptive gain sliding mode observer)are combined to achieve PMSLM sensorless control in full speed domain.Using Matlab/Simulink simulation platform,it can be seen that this PMSLM sensorless control based on hysteresis switching method can effectively achieve the speed and position estimation in the full speed domain.