Research On Sensorless Control Of The Linear Flux-switching Permanent Magnet Motor

With the fast development of the national economy,the requirements of the dynamic performance,the volume,the cost and the reliability of the drive system are improved in the long distance transportation drive system.The linear motors can produce the linear motion without the mechanical conversion devices.Hence,the linear motors have been applied in the industry.The permanents and the armature windings of the linear flux-switching permanent(LFSPM)motor are all located on the short mover,while the secondary only consists of low cost iron.Therefore,the LFSPM motor incorporates the advantages of low cost and simple secondary of linear switched reluctance motor and high efficiency of linear permanent magnet synchronous motor in long distance drive system.In order to achieve the high-performance vector control of the LFSPM motor,a linear encoder is needed to detect the mover position and speed,which will increase the cost of the system and decrease the reliability.Hence,the sensorless control of LFSPM motor is the key for this motor.First,the background and significance of the research are described.And the sensorless control algorithms of the permanent magnet synchronous motors are overviewed.Second,the basic structure and working principle of the LFSPM motor are introduced,and the mathematical model of LFSPM motor in dq axis is established.The control stategy of id=0 for the LFSPM motor is confirmed.The simulation model of the vector control for the LFSPM motor is built to verify the validity of the control system.Then,the vector control of LFSPM motor is validated by the experimental results.Third,the sensorless control method of LFSPM motor based on the sliding mode observer(SMO)is proposed.The validity and feasibility of the proposed sensorless control system are analysed and investigated.In order to reduce the chattering of the control system,a sigmoid function insteaded of the switching function is used in SMO.Then,the simulation and experiments of sensroless control of LFSPM motor based on the SMO are operated,and the feasibility of the proposed control system is verified by the simulation results and experimental results.Then,the extended Kalman filter is proposed to estimate the mover position and mover speed.The space state equations of the LFSPM motor is builted,and the steps for estimating the mover position and mover speed by the extended Kalman filter is deduced.Then,according to lots of simulation and experimental results,the estimated accuracy and control performance of the sensorless control of the LFSPM motor based on the EKF are investigated deeply.The results show that the sensorless control system has good dynamic and static characteristics.At last,the experiment platform is built,and the hardware and software of the drive system are expatiated,which lays the foundation of the experiment.