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:
Mar. 07, 2000
Filed:
Aug. 13, 1998
Barry Male, West Granby, CT (US);
Unitrade Corporation, Merrimack, NH (US);
Abstract
A motor controller controls motor rotational speed by repeatedly executing a sequence of operations. Initially, a pulse is generated that causes a predetermined fixed current to be supplied to the motor winding for a predetermined driving interval. The winding current is forced to zero after the pulse has occurred. A settling interval is allowed to pass in which the back EMF across the motor winding stabilizes, and then the winding back EMF is compared to a velocity command voltage representing the desired rotational speed of the motor. If at the end of the settling interval the back EMF is less than the velocity command voltage, indicating that the motor speed is less than the desired speed, then a new control cycle is begun, starting with the assertion of the current-driving pulse. However, if the back EMF of the motor winding exceeds the velocity command voltage at the end of the settling interval, indicating that the motor speed is greater than the desired speed, then the controller continues to supply zero current to the motor winding while the motor velocity decays. This velocity decay interval ends when the back EMF no longer exceeds the velocity command voltage, at which time a new control cycle is begun.