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:
Feb. 20, 1990
Filed:
Apr. 18, 1989
Applicant:
Inventors:
Kazuhiko Doi, Narita, JP;
Yasutami Kito, Tokyo, JP;
Assignee:
Otis Elevator Company, , CT (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02M / ;
U.S. Cl.
CPC ...
363 95 ; 363 37 ; 363 98 ;
Abstract
A star-connected sensing resistor at the A.C. output side of a PWM inverter detects an output voltage across the resistor, a PWM control according to the invention then amplifies the detected voltage, compares the amplified voltage with a sine wave voltage command signal, amplifies the compared output in a P-I amplifier having a definite gain for a D.C. current, compares the P-I amplified output to a carrier and thus provides a PWM output for controlling the inverter.