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. 11, 2001
Filed:
Feb. 08, 2000
Hitachi, Ltd., Tokyo, JP;
Abstract
An apparatus for executing field weakening control comprises a means for computing a start rotational speed of field weakening control based on a ratio of a battery voltage used in a normal operation to a detected battery voltage in execution of only field weakening control without generating a torque, and an interpolation means for carrying out linear interpolation on at least two values selectively fetched from a plurality of current tables in accordance with a battery voltage to find a field weakening current. The apparatus provided by the present invention is further characterized in that, in addition to correction of a start rotational speed of the field weakening control, a field weakening current is corrected in accordance with a ratio of a rated battery voltage used in a normal operation to a detected battery voltage.