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. 25, 2006
Filed:
Sep. 30, 2004
Jaydip Bhaumik, Rosemount, MN (US);
Jason P. Brenden, Woodbury, MN (US);
Dames A. Dahlberg, Eagan, MN (US);
Michael Peterson, Eagan, MN (US);
Ross Wilson, Menlo Park, CA (US);
Jaydip Bhaumik, Rosemount, MN (US);
Jason P. Brenden, Woodbury, MN (US);
Dames A. Dahlberg, Eagan, MN (US);
Michael Peterson, Eagan, MN (US);
Ross Wilson, Menlo Park, CA (US);
Agere Systems Inc., Allentown, PA (US);
Abstract
A three-phase spindle motor has three terminals each driven with pulse width modulated signals. Rotation of the motor is controlled by iteratively measuring an electrical period of the motor, determining a rotational position of the motor, and synchronizing the sinusoidal pulse width modulation of the spindle motor with the measured electrical period. The electrical period of the motor is measured by detecting zero crossings in the a back electromotive force induced at a first terminal of the motor and determining the time between successive zero crossings. The rotation position of the motor is determined based upon the last measured electrical period and a location of last detected zero crossing. The zero crossings are detected by selecting a time window during which the back electromotive force signal is sensed for zero crossings. The time window is selected as a function of the last measured electrical period and the rotational position of the motor.