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:
Feb. 06, 2001
Filed:
Dec. 20, 1999
Ryuichi Oguro, Fukuoka, JP;
Takeshi Kamei, Fukuoka, JP;
Kabushiki Kaisha Yaskawa Denki, Kitakyushu, JP;
Abstract
In order to estimate a magnetic pole position of a permanent magnet type brushless motor, the following steps are conducted. A given &ggr; axis and a given &dgr; axis in an advanced from the &ggr; axis by an electrical angle of 90° are set. A closed-loop electric current control system in the &ggr; axis direction is formed while forming an open-loop electric current control system in the &dgr; axis direction. It is calculated an interference current generating in the &dgr; axis direction when a current command in the &ggr; axis direction is given as a stepwise alternating current command. The &ggr; axis is finely advanced by an angle of &Dgr;&thgr; when a sign of a product of an integral value of the interference current and a value of the current command in the &ggr; axis direction is positive. Alternatively, the &ggr; axis is finely delayed by an angle of &Dgr;&thgr; when the sign is negative. Thereby, the &ggr; axis is made accord with either a d axis as a true magnetic axis or with a -d axis advanced by 180° from the true magnetic axis.