Induction motor speed estimation based on rotor slot effects

The harmonic saliency signals created by rotor slot effects are found in the stator currents of most induction motors, and their frequencies are inherently correlated with the speed. In general, the relationships between speed and the signals are determined by rotor slot number, pole pairs and the way to obtain these signals. In this paper, a speed estimation scheme based on dominant rotor slot harmonic is presented. The separation and refinement of the signal are designed according to its characteristics. Then, the frequency of the signal is obtained by simplest way. Finally, speed is calculated based on the frequency information. The robustness and effectiveness of the proposed scheme have been validated by simulation and experimental results.