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:
Aug. 09, 2005
Filed:
Sep. 24, 2002
Masaki Suzui, Kyoto, JP;
Nobuyoshi Takehara, Kyoto, JP;
Seiji Kurokami, Kyoto, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
In a power conversion system having a DC power supply which has an almost fixed DC voltage to ground and a predetermined stray capacitance to ground and outputs a DC power, and a power converter which converts the DC power output from the DC power supply into an AC power by switching, the phase of an AC voltage to ground generated in the DC power supply by switching is detected, the phase of an AC ground fault current that flows through the stray capacitance to ground and the ground fault resistance of the DC power supply is detected, and the difference between the two detected phases is compared with a predetermined threshold value, thereby determining a DC ground fault in the DC power supply. With this arrangement, the ground fault state of the DC power supply can more accurately be detected. In addition, the operation efficiency of the power conversion system can be increased.