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:
Dec. 07, 1999
Filed:
Jun. 01, 1998
Tomohiko Aritsuka, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An inverter control unit includes a variable-tap-added step-down transformer. A DC energy unit is connected to a DC side of an inverter unit for supplying or consuming effective power. A control circuit controls a variable tap of the variable-tap-added step-down transformer. The control circuit includes a calculating circuit for calculating an effective value of a system voltage. A setting circuit sets an effective value command value. A deviation calculating circuit calculates a deviation between the effective value and the effective value command value. A tap command circuit operated by the system voltage outputs a tap command value corresponding to the deviation. A tap change judging circuit determines whether an inverter current at least equal to a rated value is output with a change in the variable tap. A tap command circuit changes the tap command value on the basis of the determination of the tap change judging circuit. A tap command value selecting circuit selects any one of the two tap command values. A tap changing circuit changes the variable tap on the basis of the tap command value selected by the tap command value selecting circuit.