Research On Direct Thrust Force Control System Of Permanent Magnet Linear Synchronous Motor

Permanent magnet linear synchronous motor (PMLSM) has double merits of the permanent magnet motor and the linear motor, it can output linear motion trajectory, when it has not any intermediate transmission mechanism, so can be applied to various feed lifting system. In recent years, with the development of motor control technology, the PMLSM has been used more and more widely. By comparing the merits and demerits of each control strategy, this paper selects the direct thrust force control (DTFC) as control mode of PMLSM.Direct thrust force control is the direct torque control (DTC) in the application of linear motor, which is a new control method after the vector control developed, its structure is simple, response speed is fast. At present, the using of linear motor in this control mode is still in the experimental stage, this article mainly studied direct thrust control aiming at the original laboratory PMLSM, and joined the improvement measures in system.First established the mathematical model of permanent magnet linear synchronous motor in α-β and d-q coordinate system, analyzed the basic principle of direct thrust control strategy and realization way, built simulation model of PMLSM traditional DTFC in Matlab\Simulink environment, and carried out the simulation experiments. We could found that the motor stator flux and electromagnetic thrust have larger pulsation from simulation result, and the system stability is poorer.In view of flux and thrust large ripple of the traditional direct thrust force control, increased some improvement measures in it, established the mathematical model in stator flux x-y coordinate system, replaced the original hysteresis controller and switch table with space vector modulation (SVPWM) technology, and joined the flux prediction step, so designed a kind of SVM-DTFC control system based on flux error observation, and also carried out simulation experiment. Comparing with the simulation results of traditional DTFC, proved the direct thrust control strategy of PMLSM and some relevant improvement measures is feasible.On the basis of simulation experiments, designed the hardware circuit of system using a dedicated motor control chip TMS320LF2407A, inverter circuit selected PM25RSA120intelligent power module produced by mitsubishi company, and designed the sampling circuit, the protection circuit, switch power, interface and display circuit. In order to improve the control performance of the system, added some anti-interference measures in designing hardware circuit. At last, designed the software process of the control system, and laid a foundation for further research.