Research Of Speed Sensorless Control Strategy Of Three-phase Induction Motor

Induction motor AC control system has played an important role in the field ofindustrial control because of its simple structure, excellent performance. With the rapiddevelopment of industrialization, the various sectors of the motor speed control systemproposed simplified structure, energy saving, high efficiency, and many otherrequirements. Without speed sensor, the control system you can become moreconvenient, reliable, cheap, by domestic and foreign scholars, and obtain more attentionfrom domestic and foreign scholars. The sensorless control system based on full-orderadaptive observer, overcome the shortcomings of low-level observer, with highobservation accuracy, fast response speed, strong robustness characteristics, especiallysuitable for the field of application of the inverter. This paper studies the inductionmotor sensorless control strategy based on the full-order adaptive observer basicprinciples, and proves its effectiveness through simulation and experiment.First, this paper analyzes the fourth-order mathematical model of induction motor,proposes an induction motor vector control system according to the rotor flux oriented.By the contrast with model reference adaptive method, the speed estimation systembased on the full-order adaptive observer, has the advantages of high precision, stronganti-interference. This paper simulates and analyzes the control system.Then, as the rotor flux accuracy is very important for the observer, starting with theinduction motor steady-state operation, according to the rotor flux reference error, theinfluence of the observer output has been analyzed, because different parameters make achange. By analyzing the amplitude-frequency characteristic and phase-frequencycharacteristic curves, when the rotor, stator resistance and mutual inductance change,the observation error decreases with the increasing frequency.Finally, the drive system experimental platform has been established, the theoryhas been verified, using the Infineon microcontroller XMC45000as the core. Adeadtime compensation method based on averaging voltage error has been adopt,reduces the current distortion. The program of full-order adaptive observer vectorcontrol has been prepared. After the start, steady state, positive experiments, in the highspeed case, the dynamic and static performance is good, the estimated rotational speedand current observations are in good agreement to the sampled signal. In summary,based on full-order adaptive observer, the method for flux observer and speedestimation, has a broad application prospects.