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:
Mar. 06, 2007
Filed:
Apr. 27, 2005
Caominh Ta, Gunma, JP;
Shuji Endo, Gunma, JP;
Hideyuki Kobayashi, Gunma, JP;
Masahide Saito, Gunma, JP;
CaoMinh Ta, Gunma, JP;
Shuji Endo, Gunma, JP;
Hideyuki Kobayashi, Gunma, JP;
Masahide Saito, Gunma, JP;
NSK Ltd., Tokyo, JP;
NSK Steering Systems Co., Ltd., Tokyo, JP;
Abstract
The present invention provides a motor drive apparatus capable of calculating an angular velocity and a rotation angle accurately in the entire rotation velocity range of a motor using a cheap Hall sensor having an inferior accuracy without using an expensive resolver having a high accuracy. The present invention includes a first angular velocity calculating means for calculating the angular velocity based on the back-EMF of the motor when it rotates at low speeds and a second angular velocity calculating means for calculating the angular velocity based on a signal from the Hall sensor when it rotates at high speeds. According to the present invention, the angular velocity and rotation angle can be calculated accurately in the entire rotation speed range using the Hall sensor under hybrid usage.