Patents by Inventor Stefan W. Lixfeld

Stefan W. Lixfeld 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).

  • Adaptive method for conversion of external power request to current setpoint to a fuel cell system based on stack performance
    Patent number: 9105892
    Abstract: A system and method for converting a fuel cell stack power request signal to a stack current set-point that considers stack performance parameters. The method includes obtaining a power-current relationship curve of the fuel cell stack to provide stack parameters including exchange current density and mass transfer coefficient. The method then calculates a slope for the stack using the parameters from the power-current relationship curve estimation that includes calculating a cell voltage at two predetermined stack current densities. The method then calculates a change in current in response to the power request signal, the stack voltage, the stack current and the calculated slope, and uses the change in current to update the current set-point for the stack.
    Type: Grant
    Filed: March 15, 2010
    Date of Patent: August 11, 2015
    Assignee: GM Global Technology Operations LLC
    Inventors: Sriram Ganapathy, Kiran Mallavarapu, Stefan W. Lixfeld, Manish Sinha
  • ADAPTIVE METHOD FOR CONVERSION OF EXTERNAL POWER REQUEST TO CURRENT SETPOINT TO A FUEL CELL SYSTEM BASED ON STACK PERFORMANCE
    Publication number: 20110223505
    Abstract: A system and method for converting a fuel cell stack power request signal to a stack current set-point that considers stack performance parameters. The method includes obtaining a power-current relationship curve of the fuel cell stack to provide stack parameters including exchange current density and mass transfer coefficient. The method then calculates a slope for the stack using the parameters from the power-current relationship curve estimation that includes calculating a cell voltage at two predetermined stack current densities. The method then calculates a change in current in response to the power request signal, the stack voltage, the stack current and the calculated slope, and uses the change in current to update the current set-point for the stack.
    Type: Application
    Filed: March 15, 2010
    Publication date: September 15, 2011
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Sriram Ganapathy, Kiran Mallavarapu, Stefan W. Lixfeld, Manish Sinha