Stator resistance tuning for PTC based induction motor drive at very low speed

This paper deals with a simple voltage model resistance estimator for predictive torque control (PTC) based induction motor (IM) drive. In PTC, flux and torque are predicted to select an optimal voltage vector to be applied to the motor by actuating a predefined cost function. Conventional PTC based control schemes provide poor performance in the very low operating frequencies when the stator flux is estimated using the voltage model, due to the changes of stator resistance during operation. In order to estimate the stator resistance, stator flux must not depend on the stator resistance. To do so, the predicted flux corresponding to the optimal voltage vector is used to estimate the stator resistance. Simulation results show that the proposed estimator can estimate the resistance accurately at very low speeds with higher loads and achieves improved stator flux estimation.