Frequency estimation for sensorless control of induction motors

In the motor control industry, DSP systems offer major improvements over analog designs, enabling notably to replace speed or position sensors by the implementation of sensorless control algorithms. In this paper, we propose a new viable method which estimates the rotor velocity from the "rotor slot harmonics" included in the stator current signals. This approach is based on both an adjustable digital filter, which is fitted to this particular application, and an extended Kalman filter whose computational burden has been reduced thanks to an additional virtual state