The Induction Motor Speed Sensorless Vector Control System

The speed sensorless vector control of induction motor technology enhances the reliability of AC driving system, and reduces the realization cost. The key problem is that how we can get the speed of motor accurately.This thesis made a study on the speed-sensorless vector control system. And built up a induction speed-sensorless vector control system on based voltage decoupling and a speed-sensorless vector control system on based model reference adaptive system (MRAS). According to the reduced order model of induction motor, a model reference adaptive speed estimation algorithm was obtained from the equations of induction motor stator voltages and currents. An improved model MRAS speed estimation model was built with variable parameters. The detailed simulation researches were tested on the speed-sensorless vector control system of induction motor using the software MatLab/Simulink. The simulation results show that this improved MRAS speed estimation model has satisfied estimation precision and dynamic performance. Some simulation models can be used in other VVVF control strategy system also.The speed estimation theory based on MRAS, in essence, is based on the ideal model of the motor speed estimation programme, which are dependent on the electrical parameters, the electrical parameters in the process of motor sports has changed greatly and thus give some of the motor stator and rotor parameters real-time identification method, in order to maintain the dynamic and static performance.Based on the traditional adaptive system, the neural network replaces the original organization in the paper. A kind of new method of speed estimation based on neural network, and the structure and learning algorithm of neural network are proposed in the paper. The simulation result shows that the vector control system of asynchronous motor based on speed estimation of fuzzy neural network has a good performance.This thesis also makes an introduction of the speed-sensorless vector control system based on DSP, the hardware circuit and the software process.