Research Of The Direct Thrust Control Strategy On The Switched Flux PMLSM

The PMLSM is widely used in the fields of industrial production,military research,because of its advantages of simple structure,fast response speed and high control accuracy.However,due to the structure characteristic of “none transmission”,end effect and cogging effect,all these problems will cause the fluctuation of the thrust,speed,stator flux,and the performance of the PMLSM are affected greatly.This paper mainly studies the switched flux permanent magnet linear motor,and builds the motor control system based on the direct thrust control method and the hardware platform created by FPGA.Firstly,theschematic andthe printed circuit Boardof the systemare are made to build the hardware circuit of linear motor control system;Then,using the Verilog hardware language,the direct force control method driving the switched flux magnetic linear motor is realized digitally;finally,theperformance of the FPGA control system are tested on the PMLSM platform,and the research of thecontrol strategy is finished.Through the high-performance control of FPGA,the system can significantly reduce the fluctuation of the flux,thrust and speed,and improve the dynamic response speed of the system,the anti-interference ability of the system,and enhance the performance of PMLSM control system.First,the research background and application prospect of PMLSM are briefly described in this paper;and then,the purpose of the research is also introduced,according to the design of linear motor control system using FPGA,which has the advantages of low loss,high efficiency and reliable control performance.Based on the detailed analysis of the mathematical model of the flux switching permanent magnet linear motor mathematical model,and the direct thrust control method,this paper builds the MATLABmodel.The simulation results verify the feasibility of the control method,and improve theperformance of the method by using the back-stepping approach.The digital design for the direct thrust control system is based on the research above.Secondly,this paper describes the hardware design of PLMSM control system in detail.The motor control system is composed of the driving circuit and the control circuit,and the design of the schematic diagram of the system control circuit is mainly introduced.The circuit takes FPGA as the core chip ofthe control system.According to the modulardesign,it can be divided into voltage and current acquisition module,speed acquisition module,analog to digital conversion module,communication module and auxiliary function module.Some useful experiences and techniques in the design of the Printed Circuit Board are introduced in the paper.The reliable hardware design can improve the accurate feedback of the current,voltage and speed signals for the system,and lay the foundation for the experiment of PMLSM.Thirdly,the digital design of the control system is realized based on FPGA.According to the modular design of electronic design automation,the overall digital system is divided into coordinate transformation module,voltage and current measurement module,speed measurement module,core method module and PI speed regulator module.The difference between linear motor and traditional motor is the difference of speed measurement mode.Based on the reliable design of hardware circuit and Verilog hardware language,the accurate measurement of speed feedback signal and the reliable transmission of the control signal can ensure the accurate control of PMLSM.Finally,this paper uses the FPGA EP3C25 Q development board,the switched flux permanent magnet linear motor,the FPGA control system based on the direct thrust control methodand the digital design to do the experiment of PMLSM control system.Data and waveforms are given to verify the reliability and the good performance of the current loop control system.The research lays the foundation for the followingspeed loop and position loop control system.