Research On Speed-sensorless Vector Control System For Induction Motor Based On DSP

Based on vector control theory and identification of stator resistance online, considering the influence of rotor time-constant, a wide-range speed control system for induction motors (IMs) is established in the thesis. The main work is as follows:1. The advantages and disadvantages of several vector control strategies are compared. The mathematical model of IMs is educed. The basic principles of voltage Space Vector Pulse Width Module (SVPWM) and field-oriented vector are explained.2. An improved parameter identification method of Extended Kalman filter (EKF) is proposed based on least square algorithm. The accuracy of the parameter estimation is obtained by interlacing two Bi-Loop recursive least squares algorithm (BLFRLS) estimator.3. By measuring stator voltage and current, a novel algorithm is presented based on the serial operation of two extended EKF models. This approach will achieve the identifications of rotor stator resistance, magnetizing inductance, rotor flux, and speed online.Experimental and simulation results show that the developed algorithm leads to smaller system error than the traditional one as well as excellent low-speed performance, and can meet the precision requirement in speed sensorless vector control system of IMs.