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:
Apr. 29, 2003
Filed:
Jul. 27, 2000
Tan Du, Plano, TX (US);
Robert E. Whyte, Jr., Dallas, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
The invention includes a method and apparatus for detecting the position of an electric motor rotor by sensing the zero crossing or polarity change of a mutual inductance associated with the motor. The use of mutual inductance provides for consistent position detection unaffected by motor speed or winding current, thus providing significant advantages over traditional back emf zero crossing detection methods. The mutual inductance zero crossing may be detected by measuring a voltage signal in a floating phase of the motor, filtering back emf and excitation components out of the measured voltage signal, and detecting a polarity change or zero crossing in the resulting mutual inductance signal.