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:
Oct. 01, 2002
Filed:
Jun. 01, 2001
Ismail Agirman, Hartford, CT (US);
Vladimir Blasko, Avon, CT (US);
Christopher S. Czerwinski, Farmington, CT (US);
Jeffrey M. Izard, Bolton, CT (US);
Edward D. Piedra, Chicopee, MA (US);
Otis Elevator Company, Farmington, CT (US);
Abstract
In a pulse width modulation-controlled, switched bridge, DC converter, the phase angle ( ) of the AC mains ( ) is provided without sensing the voltage thereof, by a phase-locked loop ( ) having one input ( ) derived ( ) from the in-phase voltage command V * ( ) and another f ( ) approximating the line frequency; the phase-locked loop is initialized at a phase angle &thgr; ( ) equal to the arctangent ( ) of the in-phase V , and quadrature V representation of estimated line voltages e , e , e ( ) derived during an initialization cycle from reconstruction of the fundamental component of the AC main currents at a phase angle ( ) changing with said frequency. Reconstruction includes providing the discrete Fourier transform (DFT, ) of signals indicative of currents ( ) in the AC mains and the inverse DFT ( ) of the resultant Fourier coefficients e , e .