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. 25, 1992
Filed:
Jan. 04, 1990
Heikki J Tuusa, Tampere, FI;
Kone Elevator GmbH, Baar, CH;
Abstract
A procedure and apparatus for the control of solid-state switches in three-phase frequency converter and rectifier/inverter bridges is disclosed. Such control employs pulse width modulation. In this procedure, the modulation pulses of each phase are generated by comparing sinusoidal modulation references in an interval-by-interval manner to at least two triangular waves with a phase shift between them. The modulator unit for implementing the procedure incorporates one or more memory circuits storing the modulation reference curves, one or more D/A converters for converting the memory circuit outputs into analog form, and comparators for producing preliminary modulation pulses by comparing the sinusoidal modulation reference signals to at least two triangular waves shifted in phase relative to each other.