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. 25, 1988
Filed:
Sep. 25, 1987
Hitachi, Ltd., Tokyo, JP;
Abstract
A first apparatus for determining instantaneous reactive currents to determine instantaneous reactive currents in every phase of a three-phase load. Three phase current signals corresponding, respectively, to phase currents of the three-phase load supplied from a three-phase power-supply source are multiplied with sinusoidal wave signals of three phases, each of which has a phase difference of 90.degree. relative to the corresponding phase voltage of the three-phase power supply source to obtain the products for three phase, respectively, which products are added together to produce a sum signal. The instantaneous reactive currents mentioned above are determined on the basis of the sum signal and the three phase sinusoidal wave signals. A second apparatus for compensating the reactive power of the three-phase load by means of a converter load circuit including a current-source type three phase converter connected in parallel with the three-phase load by making use of the instantaneous reactive currents of the three-phase load determined by the first mentioned apparatus.