Patent ID: 8115441
Filing Date: 2012-02-14
Classification: G01R,H02P

Abstract:
1. A method for making on-line measurements of a rotor time constant associated with an induction machine, the method comprising: a. interrogating the induction machine with a small signal oscillation generated at a frequency selected based on a most recent estimate of the rotor time constant; b. monitoring the response of the induction machine by monitoring a rotor flux generated in response to the small signal oscillation; c. detecting within the rotor flux a rotor flux component generated in response to the small signal oscillation; d. detecting a phase associated with the rotor flux component generated in response to the small signal oscillation; e. updating the most recent estimate of the rotor time constant and the frequency of the small signal oscillation based on the detected phase of the rotor flux component generated in response to the small signal oscillation; and f. repeating steps a-e.