Robust speed-sensorless induction motor drive for traction applications

In this paper the sensorless induction motor drive with MRAS-type speed and rotor-flux estimator is described and tested in a wide range of the rotor speed and flux. The dynamical and steady-state properties of the drive system dedicated to traction applications are tested in the low speed as well as under field weakening region. The sensorless induction motor drive is also tested from the point of view of the motor parameters changes in these two operational ranges. The speed adaptation mechanism in the MRAS-type speed and flux estimator has been improved and the speed estimator is extended with the magnetizing reactance estimator. The simulation results are verified by experimental tests, over the wide range of the motor speed changes.