Patents by Inventor Stephen Stella

Stephen Stella 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).

  • Method and apparatus for motor control
    Patent number: 6936991
    Abstract: A closed-loop permanent magnet motor control method and system optimally partitions torque and flux-weakening currents to produce a desired torque without exceeding the capability of the DC source. A maximum limit for allowable torque current and a minimum threshold for the maximum torque current are determined, and the flux current is varied based at least in part on whether the maximum torque current limit is above or below the minimum threshold while operating in a flux-weakening region to compensate for the variability of the DC source voltage.
    Type: Grant
    Filed: May 30, 2003
    Date of Patent: August 30, 2005
    Assignee: Ballard Power Systems Corporation
    Inventors: Li Chen, Roy I. Davis, Stephen Stella, Tod R. Tesch
  • Method and apparatus for motor control
    Publication number: 20040036434
    Abstract: A closed-loop permanent magnet motor control method and system optimally partitions torque and flux-weakening currents to produce a desired torque without exceeding the capability of the DC source. A maximum limit for allowable torque current and a minimum threshold for the maximum torque current are determined, and the flux current is varied based at least in part on whether the maximum torque current limit is above or below the minimum threshold while operating in a flux-weakening region to compensate for the variability of the DC source voltage.
    Type: Application
    Filed: May 30, 2003
    Publication date: February 26, 2004
    Applicant: Ballard Power Systems Corporation
    Inventors: Li Chen, Roy I. Davis, Stephen Stella, Tod R. Tesch