Speed Sensorless Direct Torque Control System Of Induction Motor Based On MRAS

Asynchronous motor is widely used because of its strong structure,strong environmental adaptability,low maintenance cost,high power and high speed.With the continuous development of modern electric and electronic technology,the AC speed control technology of asynchronous motor is mature.However,under the traditional control mode,the torque ripple of the motor is large.At the same time,the existence of speed sensor increases the manufacturing cost,and its use range is limited.Aiming at the problem that the torque ripple of asynchronous motor is large under the traditional control mode,and the speed sensor makes the application scope of motor limited,the speed sensorless technology of asynchronous motor based on fuzzy variable flux linkage is studied.Firstly,the basic structure and working principle of asynchronous motor are introduced,and the mathematical model of induction motor is analyzed.The basic principle of direct torque control(DTC)is studied,and the part of control is studied.Secondly,based on fuzzy control theory,constructing the fuzzy PI controller is constructed based on fuzzy variable flux controller,gives the design principle of fuzzy variable flux,build a direct torque control system based on variable flux.The simulation results show that the fuzzy variable flux control system can realize the nonlinear change of flux linkage,and improve the dynamic and static speed regulation performance of the system.In addition,the basic principle of model reference adaptive speed identification is studied,and the MRAS model is improved.The speed sensorless direct torque control system based on MRAS is built,and the simulation model of speed sensorless direct torque control system based on improved MRAS is built.The simulation results show that the speed sensorless direct torque control system based on the improved MRAS has better speed identification and better identification accuracy.Finally,the MRAS induction motor based on speed sensorless direct torque control system for digital realization,hardware design principle of control system is given,the control program,designed the software process.In this paper,a speed sensorless direct torque control system based on MRAS is built by studying the fuzzy variable flux controller and the improved MRAS speed identifier.It effectively reduces the torque ripple and realizes the sensorless speed identification.The simulation experiment verifies the rationality of this study and lays a theoretical foundation for the follow-up research.