Research On Vector Control System Asyachronous Motor Based On Fuzzy Control

The most commonly used control methods of frequency converter in the market are vector control and voltage-frequency ratio(V/F)control.Here are two kinds of vector control,one is sensorless vector control the other is sensor vector control.Vector control technology is widely used in the field of industrial field which requires high speed accuracy control,and the dynamic response of the motor is poor when the load is changeable.In order to solve the problem of the load is changeable,first of all we should departure from the basic principle of vector control,We need the state equation and the mathematical model of the asynchronous motor on the orthogonal coordinate system.we should get the transfer matirixes of the static three-phase coordinates turn to static two-phase coordinates(3S/2S),static two-phase coordinates turn to rotate two-phase coordinates(2S/2R).And then get the static three-phase coordinates turn to rotate two-phase coordinates transfer matrix.Secondly,three kinds of vector control system are designed,one is the rotor speed and flux linkage closed-loop vector control system,and the other is rotate spped and flux linkage vector control system with torque inner loop.The last one is a model reference adaptive vector control system.The first two kinds of control system is mainly based on the speed loop and flux linkage make corresponding improvement,increase the speed regulator(ASR),torque regulator(ATR)and flux linkage regulator(A?R),in order to realize the system for the anti-interference ability of the torque,rotate speed changes.Finally,according to the three kinds of control system to build the system model,and the simulation experiment analysis of the three kinds of system dynamic response.Based on the motor model to build above three control systems,the motor model parameters are variabel in the actual work,so that there errors with the measurement.The change of load torque will lead to the motor parameters can't be accurate identification which reduce the static and dynamic response of the system.In view of this situation,an adaptive fuzzy PID vector control system is designed,which adds a fuzzy PID controller to the speed regulator and torque regulator.The kind of switched fuzzy PID control system needs to adjust PID parameters manually,which can improve the dynamic performance of the system.The dynamic performance also can be improved by cascade fuzzy control system,and the adaptive characteristics of PID parameters are more suitable for field applications.Finally,by setting up the physical control experimental platform,and using cascade fuzzy PID control system,the static and dynamic response of speed vector control is improved.The results show that the fuzzy PID control system has better stability and robustness,reduces the regulation time and overshoot of the system,and has high guiding significance in practical engineering application.