Patent ID: 8373379

Claim:
A method for estimating at least one motor inductance parameter of 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 an instantaneous rotor speed of the motor, the determining the instantaneous rotor speed including calculating, via at least one processor, an instantaneous rotor slot harmonic frequency extracted from the complex current with respect to an instantaneous fundamental frequency extracted from the complex voltage; determining an instantaneous reactive power of the induction motor according to a function that includes the complex voltage and the complex current; determining at least one motor inductance parameter based, at least in part, upon the motor nameplate data and the instantaneous reactive power; and storing an indication of the at least one motor inductance parameter in at least one memory.