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. 24, 2024
Filed:
Oct. 13, 2020
Hitachi, Ltd., Tokyo, JP;
Akihiro Nakamura, Tokyo, JP;
Koichiro Nagata, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The purpose of the present invention is to provide a device monitoring technique having little restriction even on application to an already-existing device or facilitating monitoring even when a device to be monitored is in variable speed operation or under load variation. One of the representative device monitoring devices of the present invention monitors a device system using, as a power source, an AC electric motor driven by an inverter and is provided with a torque current estimation unit and a state estimation unit. The torque current estimation unit acquires information about AC currents of at least two phases and excitation current of the AC electric motor and calculates a torque current estimated value of the AC electric motor on the basis of the AC currents and the excitation current. The state estimation unit estimates the state of the device system from information including at least one of the feature amounts extracted from the torque current estimated value.