Patent · US Expired

High frequency pulse width modulation

US4567411A · kind A · utility

22Cited by

12References

1Claims

0Family size

Assignee

OTIS ELEVATOR COMPANY · US

Inventors

Kurt A. Reimann · Grosse Ile Township, US
Bernd Ackermann · Aachen, DE
Ruediger Loeb · Hennigsdorf, DE
Claus Ruther · Munich, DE

Key dates

Filing date	Mar 22, 1985
Grant date	Jan 28, 1986
Priority date	—
Expiry date	Mar 22, 2005

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10S388/912
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

A counter (24) increments several times during the duty cycle of a microprocessor (10), and a comparator (30) connected to both outputs a High signal when the microprocessor output exceeds the counter output and outputs a Low signal when the counter output is at least the microprocessor output. The microprocessor output is proportional to desired motor speed for an elevator door drive motor according to a velocity profile stored in a ROM (18). Thereby, the High:Low ratio of the comparator output is a pulse width modulation signal, which is amplified (34) for the motor (12), at a much higher frequency than the microprocessor duty cycle.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.