The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 06, 2012
Filed:
Nov. 11, 2008
Larry A. Turner, Chapel Hill, NC (US);
Roy S. Colby, Raleigh, NC (US);
Zhi Gao, Raleigh, NC (US);
Schneider Electric USA, Inc., Palatine, IL (US);
Abstract
A method of determining a quantity of rotor slots in an induction motor through analysis of voltage and current signals. An approximate slip is calculated according to an approximate slip function that is independent of a rotor slots quantity. A fundamental frequency is calculated from a representation of the voltage signal. A saliency frequency is calculated from a representation of the current signal. For each rotor slots index in a set of rotor slots indices, a slip estimate is calculated 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. A slip estimation error signal is calculated according to a slip estimation error function that includes a difference between the approximate slip and respective ones of the slip estimates. A rotor slots performance surface representative of an aggregate of the slip estimation error signals evaluated over the set of the rotor slots indices is calculated. 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 is defined.