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:
Jun. 04, 2002
Filed:
Aug. 01, 2000
Masaji Nakatani, Nara, JP;
Hideshi Ohtsuka, Tenri, JP;
Sharp Kabushiki Kaisha, , JP;
Abstract
A control unit is arranged for a synchronous motor formed of a rotor provided with a magnet. The control unit includes a 180°-conduction drive unit for performing 180°-conduction drive of the synchronous motor, a 120°-conduction drive unit for performing 120°-conduction drive of the synchronous motor, a rotation speed calculating unit for calculating the motor rotation speed, a rotation-speed-vs.-efficiency table unit storing an efficiency relative to a rotation speed of the motor, and a drive method selecting unit for selecting an optimum drive method for the current rotation speed based on the current rotation speed and information stored in the rotation-speed-vs.-efficiency table unit. Thereby, the synchronous motor performs 120°- or 180°-conduction drive in accordance with the current rotation speed to achieve the drive with an optimum efficiency.