Study On Speed Sensorless Vector Control System Of Induction Motor

In order to realize the performance of torque and speed in machines without speed sensor and new high performance drivers as vector control system with speed sensor acts, the research on speed sensorless vector control system for induction motor is noticed abroad. The kernel problem for speed-sensorless vector control is how to get motor speed and the main springboard is that rotor speed is estimated by detecting stator voltage and current and making use of motor model or anisotropy, and estimated speed is used in speed feedback system. On the basis of reading and summing up a lot of references, this dissertation construct inactive power MRAS to estimate rotor speed and take the study of speed-sensorless vector control system for induction motor comprehensively and in-depth.First, this dissertation gives several important mathematical models in rotor field oriented vector control and analyzes the structure of speed-sensorless vector control system. Adaptation law is got with Popov overstability theory and speed is estimated with inactive power MRAS without integral and stator resistor.Then, the system above is simulated with MATLAB to validate its performance. The simulation results indicate that estimated speed is precise and the system is high anti-jamming. The simulation by changing PI in MRAS indicates that the system's dynamic response becomes quicker and overshot is less and static speed error is improved. How rotor resistor changing with temperature affects speed estimation is analyzed and rotor resistance is estimated by injecting harmonic into excitation current, and simulation results prove that this method is correct and effective.Finally, this dissertation makes use of XC167CI MCU as controller and designs hardware and software for speed sensorless vector control system of induction motor. The experiment is completed at different speed and experiment results indicate that inactive MRAS is correct and effective and the performance of this system is perfect in dynamic and static state.