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:
Jan. 30, 2001
Filed:
Jul. 22, 1999
Scott E. Heeren, San Jose, CA (US);
Bryan Scott Rowan, Los Gatos, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A system for controlling a brushless dc motor includes a motor driver circuit that outputs a drive current to the motor and a power supply that provides power to the motor driver circuit. Feedback circuits provide signals indicative of: a speed of rotation of the motor and at least one of: a level of the supply voltage provided by the power supply, and the output current from the motor driver circuit. A processor analyzes the feedback signals and determines if a required change in drive current to the motor will result in a saturation or near saturation condition. If such a saturation or near saturation condition is anticipated, the processor initially determines if a change in commutation angle will avoid the saturation or near saturation condition and if yes, outputs a control signal to alter the commutation angle. If the processor determines that a change in commutation angle will not avoid the saturation or near saturation condition, wave shaping actions within the motor driver circuit are disabled so as to maintain synchronism between the motor and the frequency of the output drive current from the motor driver, at a cost of increased acoustic noise from the motor.