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:
Nov. 24, 2020
Filed:
Sep. 19, 2018
Hitachi Automotive Systems, Ltd., Hitachinaka, JP;
Masaki Hano, Isesaki, JP;
HITACHI AUTOMOTIVE SYSTEMS, LTD., Hitachinaka, JP;
Abstract
An abnormality diagnostic unit of a motor drive device has an inverter that supplies AC power to an electric motor, and a current measuring means for measuring a DC bus current of the inverter, calculates an estimated upper q-axis current limit and an estimated lower q-axis current limit based on a diagnostic q-axis voltage command value obtained by subjecting a q-axis voltage command value to an absolute value process. The abnormality diagnostic unit calculates a diagnostic q-axis current measurement based on: a q-axis current measurement calculated based on an output of the current measuring means; and sign information of the q-axis voltage command value. Then, the abnormality diagnostic unit determines whether the current measuring means is abnormal based on duration of deviation of the diagnostic q-axis current measurement from a normal range defined by the estimated upper q-axis current limit and the estimated lower q-axis current limit.