A technique for the non-intrusive measurement of the rotor speed of an induction motor has been proposed and demonstrated. An induced current harmonic due to motor dynamic eccentricity is extracted from the phase current. The frequency of this component is related to the rotor speed while its bandwidth is related to the supply frequency and the phase lock loop R-C filter cut-off frequency. The signal can also be extracted from the phase current reconstructed from the d.c. link current. The use of switched capacitor filters allows the rotor frequency component to be extracted from the phase current, in spite of any frequency variation in the motor supply.
|Number of pages
|IEE Conference Publication
|Published - 1990
|Fourth International Conference on Power Electronics and Variable-Speed Drives - London, Engl
Duration: 17 Jul 1990 → 19 Jul 1990