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:
Jul. 03, 1984
Filed:
Mar. 11, 1983
Keiji Sakamoto, Hachioji, JP;
Shinji Seki, Tokyo, JP;
Fanuc Ltd., Tokyo, JP;
Abstract
An apparatus for driving an A.C. motor includes a circuit for computing the sum of polyphase A.C. signals used to drive a pulse-width modulation circuit for controlling an inverter, and for limiting the amplitude of a current command when said sum is other than zero. When an imbalance occurs in the polyphase A.C. signals, the current command amplitude is immediately limited in accordance with the state of the imbalance to prevent saturation of a current amplifier that is operable to produce the polyphase A.C. signals by amplifying the outputs of an arithmetic circuit. These outputs are difference currents obtained by computing the difference between polyphase command currents and corresponding ones of detected polyphase currents actually applied to the A.C. motor. Preventing saturation of the current amplifier assures that the polyphase currents actually applied to the A.C. motor will be held in a balanced state at all times.