Research On The PI Control And Vibration Characteristics Of Permanent Magnet Linear Synchronous Motor

As a direct conversion device for electromagnetic field transform to electromagnetic force then to line displacement,permanent magnet linear synchronous motor(PMLSM)does not need intermediate transmission device and could directly converts the electric energy to linear mechanical energy.The structure of linear transmission device has greatly been simplified,which improves the working efficiency,and reduces the energy loss of the mechanical transmission system.It is an ideal linear mechanical transmission device,and is widely used in the field of linear drive.When employed in linear drive,the motion of PMLSM motion is carried out by the Lorenz force that produced by the three phase alternating magnetic field(also called a traveling wave magnetic field),which is generated by the magnetic field produced by secondary permanent magnets and the alternating current in the primary coil winding of the motor.Therefore,the mathematical modeling and analysis of the magnetic field of the permanent magnet is particularly important.The distribution of the magnetic field of the permanent magnet should be fully analyzed in order to better analyze the operation of the motor.In order to reduce the thrust fluctuation of linear motor,a parallel hexahedron permanent magnet Nd2Fe14 B array is built when building linear motor platform.The magnitude of magnetic induction is analyzed by Biot Safar's law in magnetic mathematical modeling.At the same time,the magnetic field is measured by Tesla meter,and the measurement results are compared with the three-dimensional electromagnetic field simulation results.In the study of the motion of PMLSM,the motion of it is caused by the alternating magnetic field,the mass of which is directly determined by the alternating currents through the coil winding.In the control of the linear motor speed regulating system,the space vector pulse width modulation(SVPWM)technology is adopted,compared with the traditional sinusoidal pulse width modulation(SPWM),the torque ripple is smaller,current harmonic is less,control current quality is higher,voltage utilization is higher and is easy to digitize.When the action time of the adjacent voltage vector and the sampling period are not in the sampling period,in order to avoid the malfunction of the switch tube,the action time of the voltage vector is compensated by inserting the zero voltage vector.Based on the working principle of SVPWM,the structure of the system is analyzed in detail.Combined with the analysis process,a speed regulating system model of SVPWM and voltage source inverter acting on linear motor(LM)is built in MATLAB/Simulink.Simulation and experimental results show that SVPWM is effective in LM speed regulation system.In the process of driving control of PMLSM,the side effect,cogging effect and load disturbance are bound to produce the thrust fluctuation for the structure characteristics of the motor.At the same time,the error of manufacturing,inhomogeneous magnetization of permanent magnets and the anisotropy of the material will emerge with thrust fluctuation,which has become a bottleneck restricting to further improve motor motion precision,which has always been a hot research spot in this field for national scholars.On the basis of classical PI control,the influence of the feed-forward control and filtering technology on the control current in the vector control is studied,and the characteristics of the q axis response current of the motor under the conditions of different parameters and loads are tested on the experimental platform.By analyzing the response current of the q axis of the motor,the influence of the response current on the electromagnetic thrust fluctuation of the motor is obtained.In order to study the vibration problem of PMLSM in the driving control process and study the dynamic characteristics of the motor,the vibration test of the PMLSM station is carried out by LMS Test.Lab.The vibration response of the motor in the horizontal direction and vertical direction under the influence of the external sinusoidal excitation signal are tested based on the theory of forced vibration.