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:
May. 22, 1990
Filed:
Nov. 14, 1988
Allan B Plunkett, Portland, OR (US);
Synektron Corporation, Portland, OR (US);
Abstract
A sensorless control for DC permanent magnet brushless motor includes a feedback loop connected between the motor stator windings and the inverter which controls the timer at which current is provided to the various windings in sequence. The control of the invention includes a voltage sensing network for sensing the back EMF on each motor winding when it is unenergized and comparing this voltage with a null point. For maximum torque this voltage has an optimum value and variation from this value produces an error signal which is integrated to produce a VCO drive signal. This signal controls the frequency of a VCO which in turn controls the switching times of the inverter.