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. 15, 2008
Filed:
May. 22, 2006
Qiang Yin, Shanghai, CN;
Russel J. Kerkman, Milwaukee, WI (US);
Qiang Yin, Shanghai, CN;
Russel J. Kerkman, Milwaukee, WI (US);
Rockwell Automation Technologies, Inc., Mayfield Heights, OH (US);
Abstract
A method and apparatus for reducing common mode noise in a three phase pulse width modulated (PWM) system the method comprising the steps of receiving modulating waveforms, identifying a first of the modulating waveforms that is instantaneously the maximum of the modulating waveforms, identifying a second of the modulating waveforms that is instantaneously the minimum of the modulating waveforms, for a first phase associated with at least one of the first and second identified waveforms, substituting a first substitute waveform for the one of the first and second waveforms, for the first phase, modifying at least one of the first substituted waveform and duty cycle signals generated by comparing the first substituted waveform with the carrier signal as a function of a first rule set to substantially minimize the effects of turn on delays and for at least one of the second and third phases, modifying at least one of the associated modulating waveform and duty cycle signals generated by comparing the modulating waveform with the carrier signal as a function of a second rule set to substantially eliminate the effects of turn on delays where the second rule set is different than the first rule set.