Patent ID: 9231512
Filing Date: 2016-01-05
CPC Classification: G01R,H02P

Claim Text:
1. A method for demodulating instantaneous rotor slot harmonic frequency for a polyphase induction motor, the method comprising: receiving measurements indicative of at least one voltage and at least one current associated with the induction motor; converting the voltage measurements to discrete-time voltage samples and the current measurements to discrete-time current samples; determining a complex voltage from the discrete-time voltage samples and a complex current from the discrete-time current samples; receiving motor nameplate data associated with the motor; determining a dynamically varying carrier frequency; determining an estimated filter bandwidth; demodulating the instantaneous rotor slot harmonic frequency based, at least in part, on the dynamically varying carrier frequency, the estimated filter bandwidth, and the motor nameplate data; and storing the demodulated instantaneous rotor slot harmonic frequency; wherein the determining the dynamically varying carrier frequency includes determining an anticipated rotor slot harmonic frequency based, at least in part, upon the complex voltage, the complex current, and the motor nameplate data.