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:
Jul. 21, 1998
Filed:
Oct. 07, 1996
Yoriyuki Takekawa, Ohsato-gun, JP;
Zexel Corporation, Tokyo, JP;
Abstract
In order to enable switching of a direct current brushless motor to sensorless operation in a very short time by a device of simple configuration, the application to a commutator section of external sync signals for accelerating the rotor is stopped upon passage of a fixed time after the start of application. The fixed time is set to one necessary and sufficient for the rotor to reach a speed sufficient for enabling sensorless operation. After the application is stopped, the commutator section is controlled to commutate drive current to the drive windings according to the rotor position by commutation control signals output by a position feedback drive signal generator using sensorless signals from a position detection circuit based on back electromotive force voltages generated in the drive windings.