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. 04, 2001
Filed:
Jun. 01, 2000
Kiyonori Moroto, Kariya, JP;
Motoya Ito, Hekinan, JP;
Denso Corporation, Kariya, JP;
Abstract
A brushless motor composed of a cylindrical stator and a magnet rotor rotatably supported in the stator is driven by a battery. The stator includes a multi-phase armature winding to which current is supplied from the battery through a drive-control circuit. The drive-control circuit includes switching elements that are selectively turned on and off to generate a rotating magnetic field in the stator. The switch-timing of the switching elements is controlled according to a rotational position of the rotor and the battery voltage. When the battery voltage is normal, the switch-timing is set to an optimum point so that a maximum efficiency of the brushless motor is obtained. When the battery voltage becomes low, the switch-timing is advanced to secure a required motor speed. Thus, the required motor speed is always secured without using additional devices such as a voltage stabilizer or a pulse-width modulation controller.