Sensorless Control Of Permanent Magnet Linear Synchronous Motor Based On Adaptive Sliding Mode Observer

Permanent Magnet Linear Synchronous Motor(PMLSM)has the advantages of small vibration coefficient,high controllability and response ability,high power density,high efficiency,and has been widely used in high dynamic and high precision systems.However,these high-performance PMLSM drive systems often require mechanical sensors to measure the motor position in real time,which moreover boosts the dimensions and manufacture price of the motor,elecvates the chance of defeat,while sensorless control methods use design algorithms to estimate the velocity and situation of the motor.which not only increases the size and production cost of the motor,but also increases the probability of failure,while sensorless control methods use design algorithms to estimate the speed and position information of the motor.It can well solve the problem of using mechanical sensors.Therefore,this thesis uses a combination of Sliding Mode Observer(SMO)and phase-locked Loop(PLL)structure to conduct without the use of sensors control of PMLSM.Firstly,the development and research status of PMLSM and sensorless control methods are comprehensively described,the working principle and structural characteristics of PMLSM are analyzed,and the mathematical models of PMLSM under static and rotating coordinate systems are established respectively.This thesis introduces the advance and fudamentalof vector control,and builds a PMLSM vector control system based on it.Then,the influence of constant gain in traditional SMO is analyzed.Too large gain will reduce the output accuracy,while too small gain will destroy the stability of SMO,resulting in slow system response speed and short precision of observed speed and position signals.Therefore,in the case of uncertain perturbations,smooth optimal estimates of PMLSM velocity and position are required.In order to work out this issue,an adaptive gain algorithm is proposed,which can adjust the adaptive gain according to the operating state of the system,and the adaptive gain SMO is designed.Through the simulation analysis of the adaptive gain SMO and the comparison with the traditional SMO,the superiority of the SMO in response speed is proved.Finally,in order to reduce chattering generated output curve of the burr phenomena and the influence of the error function is too complex,designing a PLL based on tangent function structure to combined with adaptive gain SMO,PLL based on tangent function structure compared with the traditional PLL structure can be not affected by velocity direction change and can be simplified error function and improve precision of the estimation error,weakens burrs.Meanwhile,the steadiness of the system is verified by using the Lyapunov function,and the robustness of the system is proved by theory.Through the simulation analysis of the sensorless control system,it is proved that the combination of tangential function PLL structure can reduce chattering and burr phenomenon,and can improve the dynamic performance and undisruption capacity of the system compared with the traditional SMO sensorless control system.