Rotor Flux Estimation for Low Speed Induction Motor Sensorless Drives with MRAS

摘要

In order to realize the sensorless induction motor drives with the vector control strategy, the rotor flux and the torque current are generally used to find the rotor speed. In this paper, an improved rotor flux estimation method is proposed to enhance the performance in low and zero speed condition. For accurate rotor flux and torque current estimation, the flux reference is obtained by using the modified low pass filter (LPF) and a high pass filter (HPF) is added in order to remove errors in magnitude and phase around the filter cut-off frequency. And also, the rotor speed is detected to achieve sensorless induction motor vector control with the aid of the model reference adaptive system (MRAS) scheme. Thanks to the accurate flux estimation, the steady state performance becomes better especially in low and zero speed conditions. Simulation and experimental results verify the effectiveness of the proposed system.