Patents by Inventor John C. Stafney

John C. Stafney 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 of determining average current in a PWM drive
    Patent number: 7440821
    Abstract: A method of yielding the average current in a PWM driven coil for an electrohydraulic valve. The method includes transmitting a feedback signal into a Finite Impulse Response filter to take multiple signal samples in order to calculate and average value of current within one cycle. This average value is transmitted to an algorithm that generates a pulse width signal that drives the coil of the electrohydraulic valve in the next system cycle.
    Type: Grant
    Filed: January 2, 2004
    Date of Patent: October 21, 2008
    Assignee: Sauer-Danfoss Inc.
    Inventors: Joseph J. Schottler, John C. Stafney