Rearch On Asynchronous Motor Vector Control System Based On Fuzzy PI

Universal converter is widely used in the market,there are two main control methods:V/F control and vector control.Both of the control methods can be divided into the speed sensor vector control and speedless sensor vector control.With increase of speed control of high precision requirements for industrial fields,the more vector control technology have been applied.But in the case of the changing motor load,especially speed sensorless vector control,the dynamic performance of the motor is poor.For the changing motor load,first of all,Proceed from the vector control principle,deduced vector control 3 s/2s,2s/2r,3s/2r altogether coordinate transformation matrix and conclude asynchronous motor mathematical model and the equation of state in the orthogonal coordinate system.Then the paper design three vector control systems:one is speed-flux closed loop vector control system,another is speed-flux with torque inner loop,the other is speedless sensor vector control with model reference adaptive system.The first two control systems mainly improve speed loop and flux loop,add ASR,ATR,A?R,improve anti-interference capability for changing load.Finally set up three kinds of model of control system and simulation experiment shows that three systems fast dynamic response.Above three control systems are base on motor model,which always changes in industrial fields and causes deviations of speed precision,especially speed sensorless vector control estimates rotate speed,basing on motor model.Changing load torque also causes inaccuracy of motor parameter identification and reduce the dynamic response.Therefore,the paper design fuzzy PI vector control system.This system add fuzzy PI controler outside speed loop.Swich fuzzy PI control system fast dynamic response,but PI parameters must be adjusted manually.Cascade fuzzy PI control system not only fast dynamic response,but also self-adaption is easily applied at industrial fields.Finally,experiment set up PLC-Matlab joint experiment platform,adopt cascade fuzzy PI control system and fast dynamic response.