Patents by Inventor Ljubomir Dj. Varga

Ljubomir Dj. Varga 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).

  • Patent number: 4990001
    Abstract: A method of synthesizing drive systems, including dc, synchronous and asynchronous ac, and step motor drive systems, of instantaneous response and zero error in both transient and steady state with respect to an input command and of infinite disturbance rejection ratio with respect to a load torque changes, comprising an inner positive current feedback of exactly specified nature and value of its transfer function forcing the motor impedance to zero for load independence, and further comprising control functions in a direct path with respect to both position and velocity feedback loop and in a feedforward path of exactly specified values which, together with the inner positive current feedback loop, provide for the zero-dynamics system transfer function with respect to the command with an associated instantaneous response.
    Type: Grant
    Filed: January 22, 1990
    Date of Patent: February 5, 1991
    Inventors: Novica A. Losic, Ljubomir Dj. Varga
  • Patent number: 4980620
    Abstract: A method of synthesizing a system which forces finite value of an impedance to zero comprising a positive voltage feedback of a prescribed amount of voltage feed back and a negative voltage feedback to ensure stability of the system, whereby no current through the impedance is sensed and no parameters of the impedance are required to be known implying minimization of measurement noise and adaptive/self-tuning operation, respectively, in applications in which the method is used to synthesize load independent switch mode power converters and electric motor drive systems, incorporating any kind of motor, of infinite disturbance rejection ratio and zero order dynamics.
    Type: Grant
    Filed: April 2, 1990
    Date of Patent: December 25, 1990
    Inventors: Novica A. Losic, Ljubomir Dj. Varga
  • Patent number: 4973174
    Abstract: A method of synthesizing a system which forces finite value of an impedance to zero comprising a positive current feedback of a prescribed functionalism and a negative voltage feedback to ensure stability of the system. The prescribed functionalism of the current loop uses arithmetic elements as well as voltage and current measurements to provide for a parameter-free synthesis of the converter whereby the converter operates in the measurement-based mode, the measured variables being the voltage and the current associated with the impedance of interest, without a need to supply values of both resistive and reactive components of the impedance of interest. The converter is used in synthesizing electric motor drive systems, incorporating any kind of motor, of infinite disturbance rejection ratio and zero-order dynamics and without specifying the resistive and the inductive values of the motor impedance.
    Type: Grant
    Filed: February 26, 1990
    Date of Patent: November 27, 1990
    Inventors: Novica A. Losic, Ljubomir Dj. Varga