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:
Mar. 31, 1987
Filed:
Aug. 29, 1985
Tomotaka Ito, Aichi, JP;
Katsuhiko Chonan, Aichi, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An inverter control circuit produces pulse width modulated waveform patterns approximating an a.c. power sine wave signal from a sequence of data words stored in ROM wherein the sequence is cycled over an interval corresponding to 7.5.degree. or 15.degree. of the desired sine wave. Respective portions of a 0.degree.-60.degree. segment and a 120.degree.-180.degree. segment of the desired sine wave are generated from corresponding bits of the words during successive 7.5.degree. or 15.degree. intervals. The 60.degree.-120.degree. segment is approximated by a steady state signal. Inversions of the 0.degree.-60.degree., 60.degree.-120.degree. and 120.degree.-180.degree. segments form the corresponding 180.degree.-240.degree., 240.degree.-300.degree. and 300.degree.-360.degree. segments. Selection of the appropriate generated segments during successive 60.degree. intervals produces one or more phases of the desired power signal. Further reduction in ROM requirement is made by stored data corresponding to only the first 30.degree. portions of the 0.degree.-60.degree. and 120.degree.-180.degree. segments; the full 60.degree. segments are formed by reversing the read out sequence, as well as the selector operation, during the second 30.degree. portion of the 60.degree. segments.