Patents by Inventor Joerg Kretschmann

Joerg Kretschmann 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).

  • Direct power control with component separation
    Patent number: 8698461
    Abstract: The invention relates to a method to control power output of a doubly-fed induction machine to a grid including the steps of measuring grid voltage and grid current in a three phase coordinate system, transforming grid voltage and grid current into a stator frame coordinate system, decomposing the grid voltage and grid current in the stator frame coordinate system in a positive sequence system and in a negative sequence system, calculating active and reactive power in the positive and negative sequence system, and controlling active and reactive power in the positive and negative sequence system.
    Type: Grant
    Filed: September 11, 2008
    Date of Patent: April 15, 2014
    Assignee: Woodward Kempen GmbH
    Inventors: Stephan Engelhardt, Joerg Kretschmann
  • Device for controlling a double-fed asynchronous machine
    Patent number: 8653683
    Abstract: The invention relates to a device and method for controlling a double-fed asynchronous machine (4), preferably for a power plant, in particular for a wind or water power plant. The device includes an indirect converter (6) which is connected on the rotor side to the double-fed asynchronous machine (4). The indirect converter (6) includes a rotor-side converter (20) and a line-side converter (24). At least one control element (8) is provided for controlling the indirect converter (6). At least one software-based and/or hardware-based damping element (40, 46, 48, 120) is provided which has changeable damping characteristics.
    Type: Grant
    Filed: May 19, 2011
    Date of Patent: February 18, 2014
    Assignee: Woodward Kempen GmbH
    Inventors: Stephan Engelhardt, Joerg Kretschmann
  • DEVICE FOR CONTROLLING A DOUBLE-FED ASYNCHRONOUS MACHINE
    Publication number: 20110260454
    Abstract: The invention relates to a device and method for controlling a double-fed asynchronous machine (4), preferably for a power plant, in particular for a wind or water power plant. The device includes an indirect converter (6) which is connected on the rotor side to the double-fed asynchronous machine (4). The indirect converter (6) includes a rotor-side converter (20) and a line-side converter (24). At least one control element (8) is provided for controlling the indirect converter (6). At least one software-based and/or hardware-based damping element (40, 46, 48, 120) is provided which has changeable damping characteristics.
    Type: Application
    Filed: May 19, 2011
    Publication date: October 27, 2011
    Applicant: WOODWARD KEMPEN GMBH
    Inventors: Stephan Engelhardt, Joerg Kretschmann
  • DIRECT POWER CONTROL WITH COMPONENT SEPARATION
    Publication number: 20110215775
    Abstract: The invention relates to a method to control power output of a doubly-fed induction machine to a grid including the steps of measuring grid voltage and grid current in a three phase coordinate system, transforming grid voltage and grid current into a stator frame coordinate system, decomposing the grid voltage and grid current in the stator frame coordinate system in a positive sequence system and in a negative sequence system, calculating active and reactive power in the positive and negative sequence system, and controlling active and reactive power in the positive and negative sequence system.
    Type: Application
    Filed: September 11, 2008
    Publication date: September 8, 2011
    Applicant: WOODWARD KEMPEN GMBH
    Inventors: Stephan Engelhardt, Joerg Kretschmann