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. 23, 1991
Filed:
Dec. 04, 1989
James F Bausch, West Linn, OR (US);
Synektron Corporation, Portland, OR (US);
Abstract
A low noise, high bandwidth, sensorless vector control for a brushless DC motor includes a phase locked loop control having a digital counter and ROM look-up table which is responsive to a VCO to generate digital signals representing the sine and cosine of the instantaneous phase angle of the VCO. These signals are modulated by a current command and applied to a two-phase to three-phase converter. A flux sensor senses the air gap flux in the three motor coils and converts this signal to quadrature components which are compared with the output of the look-up table to derive a phase error signal that drives the VCO. Another feature of the invention is a timed self-starting network that cause the VCO frequency to ramp upwards then automatically switch to loop control without any abrupt change in the frequency of the VCO.