Patent ID: 8131482

Claim:
A computer implemented method of determining a quantity of rotor slots in an induction motor through analysis of voltage and current signals, comprising: calculating, via one or more processors, an approximate slip according to an approximate slip function that is independent of a rotor slots quantity; calculating, via one or more of the processors, a fundamental frequency from a representation of the voltage signal; calculating, via one or more of the processors, a saliency frequency from a representation of the current signal; for each rotor slots index in a set of rotor slots indices: calculating, via one or more of the processors, a slip estimate according to a slip estimation function that includes the saliency frequency, a saliency order, the fundamental frequency, a rotor slots index in the set of rotor slots indices, and a quantity of poles of the motor, such that the slip estimate is evaluated at respective ones of the set rotor slots indices, calculating, via one or more of the processors, a slip estimation error signal according to a slip estimation error function that includes a difference between the approximate slip and respective ones of the slip estimates, and calculating, via one or more of the processors, a rotor slots performance surface representative of an aggregate of the slip estimation error signals evaluated over the set of the rotor slots indices; defining a rotor slots quantity equal to the rotor slots index corresponding to a minimum of the rotor slots performance surface over at least a portion of the set of the rotor slots indices; and storing the rotor slots quantity.