Control Strategy Of Permanentmagnet Synchronous Motor

Direct torque control (DTC) theory was first proposed by two scholars ofM.Depenbrock and I.Takahashi from Germany and Japan in the control theory ofasynchronous motors in1980s. Until1990s, Yuwen Hu and other scholars proposed theapplication of direct torque control theory on permanent magnet synchronous motor.Permanent magnet synchronous motor is made by high-energy rare earth permanentmagnet materials. It’s compared with other drive motor with high efficiency, simplestructure to easy implement, good control characteristics and power density due to itscentral rotor without field winding, Therefore, permanent magnet synchronous motor hasbeen widely used in recent years, meawhile its control algorithms have also beenextensively studied.This paper first introduced the current situation about main structure andclassifications of permanent magnet synchronous motors. Permanent magnet synchronousmotors is analyzed in a variety of coordinate systems. Based on that, the DTC system forthe permanent magnet synchronous motors were established. The simulation results showthat it has a good dynamic performance, however, the system has a large fluctuation forthe torque and the flux linkage, a poor ability of anti-interference and other short comes.Secondly, in response to those problems, a fuzzy control module was used in thispaper, instead of hysteretic comparator and switch selected table, and then design theactive disturbance rejection controller(ARDC), aimed at the seriously-affected quality bydynamic environment of the PID controller, which is used in the traditional DTC for thepermanent magnet synchronous motors, with a contradiction between “fast” and“overshoot”, a weak anti-disturbance capacity for the terms of the time-dependentperturbation, and the hard-found set of parameters, which can be adapted to differentspeed and load.Finally, this article builds a DTC system for the permanent magnet synchronousmotors on the basis of the fuzzy ADRC and via MATLAB/Simulink platform for thesimulation study. Compared with the traditional DTC system for the permanent magnet synchronous motors, the improved system effectively suppress the ripple of the torque andthe flux linkage of the permanent magnet synchronous motors, and it has high controlprecision, fast response, strong anti-interference ability during the speed changing.