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. 05, 2005
Filed:
Mar. 25, 2002
Harunobu Nukushina, Fuji, JP;
Harunobu Nukushina, Fuji, JP;
Toshiba Carrier Corporation, Tokyo, JP;
Abstract
A current detection method for an electric motor which detects phase currents of the electric motor driven by a power converter that provides ON/OFF control of bridge-connected switching elements, based on a pulse-width modulation excitation pattern, to convert a direct current into poly-phase alternating currents. The method includes connecting a current detecting element which produces a signal corresponding to a current value at the direct current side of the power converter and changing the pulse-width modulation excitation pattern by executing a shift of time of any of the phases of the pulse-width modulation excitation pattern so that a signal directly or indirectly corresponding to the phase currents is produced at the current detecting element. The method also includes detecting the phase currents of the electric motor based on the signal produced at the current detecting element and the excitation pattern which has been changed.