Patents by Inventor Vijay Maddali

Vijay Maddali 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: 7466088
    Abstract: A controller estimates a motor position. The controller includes a driver and an injector. The driver generates a fundamental control signal. The injector generates a position carrier voltage that superimposed on the fundamental control signal. The injector alters the magnitude of the carrier voltage signal in response to the corresponding amplitude of the fundamental control signal. In a disclosed example, the injector increases the carrier voltage signal magnitude as the fundamental control current signal approaches a zero crossing. The injector then gradually decreases the carrier voltage signal magnitude as the fundamental control current signal magnitude increases from zero.
    Type: Grant
    Filed: December 16, 2005
    Date of Patent: December 16, 2008
    Assignee: Hamilton Sundstrand Corporation
    Inventors: Charles J. Romenesko, Vijay Maddali
  • Publication number: 20070138880
    Abstract: A controller estimates a motor position. The controller includes a driver and an injector. The driver generates a fundamental control signal. The injector generates a position carrier voltage that superimposed on the fundamental control signal. The injector alters the magnitude of the carrier voltage signal in response to the corresponding amplitude of the fundamental control signal. In a disclosed example, the injector increases the carrier voltage signal magnitude as the fundamental control current signal approaches a zero crossing. The injector then gradually decreases the carrier voltage signal magnitude as the fundamental control current signal magnitude increases from zero.
    Type: Application
    Filed: December 16, 2005
    Publication date: June 21, 2007
    Inventors: Charles Romenesko, Vijay Maddali
  • Publication number: 20060159213
    Abstract: A fault-tolerant synchronisation source for excitation control of a three-phase generator system that combines point of regulation (POR) signals representing parameters comprising voltage and current for each phase at the POR to generate a fault-tolerant synchronisation signal.
    Type: Application
    Filed: January 14, 2005
    Publication date: July 20, 2006
    Inventors: Vijay Maddali, Michael Hanson
  • Publication number: 20060119325
    Abstract: The present invention is a generator control system where each generator in the system has an associated controller. Each controller communicates generator data or information with the other controllers in the generator control system. Each of the controllers includes a digital signal processor for analyzing the generator signal from the associated generator and information from the other controllers in the generator control system. The controllers each compare their generator signal with a system average and adjust the associated generator until the generators all supply equal amounts of power to the system.
    Type: Application
    Filed: December 7, 2004
    Publication date: June 8, 2006
    Inventors: David Mrowiec, William Peterson, Eric Henderson, Vijay Maddali, Wayne Oldenburg
  • Publication number: 20060061319
    Abstract: A carrier injection sensorless (CIS) starting control system that is capable of determining the angular position and velocity of a rotor for a wound field synchronous machine at or near rest and comprises north-south pole determination and a variable or dual frequency carrier signal for improved performance throughout the start sequence for the machine.
    Type: Application
    Filed: September 22, 2004
    Publication date: March 23, 2006
    Inventors: Albert Markunas, Vijay Maddali, William Peterson, Charles Romenesko
  • Patent number: 6850043
    Abstract: An excessive voltage protection system for a variable frequency generating system detects single point failures in a generator control unit and prevents excessive voltages at a point of regulation (POR) in the system. The generator control unit is designed to detect failures, such as a loss of three-phase sensing capability, switch failure in the exciter drive circuit, and/or exciter current loop failure. If a failure occurs, the generator control unit stops operation of the exciter drive circuit, preventing the voltage at the POR from rising to undesirable levels.
    Type: Grant
    Filed: January 30, 2003
    Date of Patent: February 1, 2005
    Assignee: Hamilton Sundstrand Corporation
    Inventor: Vijay Maddali
  • Patent number: 5554923
    Abstract: A voltage regulator for a DC power generation system which is comprised of a prime mover driven generator producing an AC voltage output which is rectified to a DC voltage output for use by the system senses the AC voltage output and the DC voltage output, and selects the lower of these two for comparison with a voltage reference to produce a voltage error output signal for use in controlling the DC voltage output. The voltage regulator further comprises tuned compensation of the error output signal prior to use in controlling the DC voltage output. The tuned compensation comprises a proportional-integral lead-lag network. The voltage regulator additionally senses the AC current generated by the generator, and adjusts at least one zero location of the compensation network in response thereto to improve stability margins during light loading conditions, and to improve transient performance requirements under heavier loading conditions.
    Type: Grant
    Filed: June 1, 1995
    Date of Patent: September 10, 1996
    Assignee: Sundstrand Corporation
    Inventors: Vijay Maddali, John F. Defenbaugh, Hassan Mansir
  • Patent number: 5068591
    Abstract: An electrical generating system is driven by a variable speed prime mover through a constant speed drive. A speed control, as a proportional integrator responsive to frequency error, controls the constant speed drive. Stability and speed of response of the system are improved by the inclusion of one or more of the following in the speed control: a lead/lag filter between the output of proportional integrator and the constant speed drive; an adaptive gain circuit for the frequency error signal ahead of the proportional integrator; an adaptive integrator for delaying integrator operation on occurrence of a load current change; a nonlinear gain circuit in parallel with the proportional integrator to increase the control signal as the error signal increases; or load current or input speed bias signals added to the control signal to reduce the range of integrator output.
    Type: Grant
    Filed: November 15, 1989
    Date of Patent: November 26, 1991
    Assignee: Sundstrand Corporation
    Inventors: Lon Hoegberg, Vijay Maddali