Patents by Inventor Hans Pfitzer

Hans Pfitzer has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7247955
    Abstract: A closed loop power converter circuit of a UPS or other power supply includes a pulse width modulator circuit in a forward path of the closed loop power circuit. A compensation circuit provides pulse width commands to the pulse width modulator at a first rate. A feedback circuit digitally filters samples of an output of the closed loop power converter at a second rate greater the first rate and that provides the filtered samples to the compensation circuit. In some embodiments, the compensation circuit may be operative to compensate for the phase lag associated with a low pass output filter.
    Type: Grant
    Filed: September 6, 2002
    Date of Patent: July 24, 2007
    Assignee: Eaton Power Quality Corporation
    Inventors: John G. Tracy, Frederick Tassitino, Jr., Hans Pfitzer, Rennie Bobb, Julius Rice
  • Publication number: 20040046456
    Abstract: A closed loop power converter circuit of a UPS or other power supply includes a pulse width modulator circuit in a forward path of the closed loop power circuit. A compensation circuit provides pulse width commands to the pulse width modulator at a first rate. A feedback circuit digitally filters samples of an output of the closed loop power converter at a second rate greater the first rate and that provides the filtered samples to the compensation circuit. In some embodiments, the compensation circuit may be operative to compensate for the phase lag associated with a low pass output filter. For example, the compensation circuit may include a high pass IIR filter, operating at the first rate, that compensates for a pole associated with the low pass output filter, while the feedback circuit includes a low pass filter, operating at the second rate, that compensates for a frequency response peak associated with the high pass filter.
    Type: Application
    Filed: September 6, 2002
    Publication date: March 11, 2004
    Inventors: John G. Tracy, Frederick Tassitino, Hans Pfitzer, Rennie Bobb, Julius Rice