Patents by Inventor Stefan G. Johansson

Stefan G. Johansson 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).

  • Ground fault detection
    Patent number: 7719285
    Abstract: The present invention relates to a ground fault detection arrangement for a synchronous three-phase electrical machine, and an electrical system comprising a ground fault detection arrangement and a synchronous three-phase electrical machine. The ground fault detection arrangement injects an off-nominal frequency voltage between a neutral point of the synchronous three-phase electrical machine and ground and measure resultant currents to detect a ground fault.
    Type: Grant
    Filed: February 18, 2009
    Date of Patent: May 18, 2010
    Assignee: ABB Research Ltd.
    Inventors: Stefan G. Johansson, Marek Fulczyk, Tord Bengtsson, Sture Lindahl, Gabriel Olguin
  • Ground Fault Detection
    Publication number: 20090160454
    Abstract: The present invention relates to a ground fault detection arrangement for a synchronous three-phase electrical machine, and an electrical system comprising a ground fault detection arrangement and a synchronous three-phase electrical machine. The ground fault detection arrangement injects an off-nominal frequency voltage between a neutral point of the synchronous three-phase electrical machine and ground and measure resultant currents to detect a ground fault.
    Type: Application
    Filed: February 18, 2009
    Publication date: June 25, 2009
    Inventors: Stefan G. Johansson, Marek Fulczyk, Tord Bengtsson, Sture Lindahl, Gabriel Olguin
  • Rotating asynchronous converter
    Patent number: 7259491
    Abstract: A rotating asynchronous converter and a generator device having a first stator connected to a first AC network with a first frequency f1, and a second stator connected to a second AC network with a second frequency f2. The converter has a rotor which rotates in dependence of the first and second frequencies f1, f2. The stators each have at least one winding formed of at least one current-carrying conductor, and an insulation system, formed of semiconducting layers each forming an equipotential surface, and a solid insulation between the semiconducting layers.
    Type: Grant
    Filed: March 30, 2005
    Date of Patent: August 21, 2007
    Assignee: ABB AB
    Inventors: Mats Leijon, Thorsten Shütte, Christian Sasse, Udo Fromm, Stefan G. Johansson