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:
Oct. 12, 2004
Filed:
Sep. 16, 2002
David Messersmith, Kenosha, WI (US);
Rockwell Automation Technologies, Inc., Mayfield Heights, OH (US);
Abstract
A method and apparatus for operating a motor controller to cause balanced positive and negative current half-cycles in a motor phase, the method comprising the steps of, for an occurring half-cycle, identifying the most recently obtained valid shut-off angle, identifying the fire angle immediately preceding the identified shut-off angle, mathematically combining the identified fire angle and the identified shut-off angle to identify a next virtual zero crossing (VZC) angle, mathematically combining the next VZC angle and the notch angle to determine a fire angle for the occurring half-cycle and repeating the method for the next half-cycle.