Research On Control Strategy Of Linear Motor Drive Platform

In order to enhance the speed response and accuracy of permanent magnet linear synchronous motor(PMLSM),both hardware and software platform are designed in this paper,which can acquire higher accuracy,efficiency and speed.The whole drive system is designed based on field oriented control(FOC),space vector pulse width modulation(SVPWM),improved current proportional-integral(PI)controller and nonsingular terminal sliding mode control,which is verified as effective in promoting both steady state performance and dynamic response.First of all,on basis of comparison between bilateral ironless permanent linear motor and unilateral iron core permanent linear motor,the detent force fluctuation of the latter is analyzed and simulated.Meanwhile,mathematical mode of PMLSM of d-q rotating coordinate system is introduced,which is the theoretical basis of control strategy simulation and experiment.Both SVPWM and FOC are the drive system key technologies,which is explained through mode establishment and principle introduction.Then,an improved PI current controller is implemented in order to solve the one-shot delay of digital signal processor(DSP).Besides,anti-saturation integral PI controller is also used to promote position response.Next,a modified terminal sliding mode control is applied to enhance the velocity-loop and position-loop.All of the strategies above are simulated and verfied as effective in Matlab/Simulink.Afterwards,the hardware of PMLSM drive system is designed,which includes TMS320F2812 DSP,DIP-IPM,signal process and isolation circuit.Software is consist of main function and main interruption function.Simultaneously,AD sampling correction and CAP optical grating signal process are introduced,which enhance the velocity mearsurement based on pulse calculation.Besides,digital filter in velocity examine is also applied.Finally,for validating the actual operation of whole drive system,experiment waveform and results in different situation are shown.The result show that both the improved PI controller and terminal sliding mode controller are effective,which can enhance the current/velocity response and the accuracy,that fully reflects the effectiveness of the control system design and lay the foundation for the follow-up research.