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:
Sep. 06, 2005
Filed:
Dec. 03, 2002
Taishi Iwanaga, Kyoto, JP;
Yasunori Yamamoto, Osaka, JP;
Taishi Iwanaga, Kyoto, JP;
Yasunori Yamamoto, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a PWM-controlled motor driving device, a phase current is prevented from undergoing an abrupt transition at phase current switching points, thereby reducing vibrations and noise of the motor. A PWM control section produces two independent PWM control pulse signals Pand P. Two energized phases, which are determined by an energization switching section, are energized with PWM control in parallel according to the PWM control pulse signals Pand P. A comparison section compares a current detection signal DS, which indicates the level of the current flowing through a motor coil, with various torque command signals TQ, TQand TQ, which are produced by a torque command signal generation section. A masking section masks comparison results CRand CRas necessary. Thus, an ON period of the PWM control pulse signal Pand that of the PWM control pulse signal Pare determined. In this way, phase current switching can be done smoothly with any torque from a low torque to a high torque, thereby preventing an abrupt phase current transition.