Patents Represented by Attorney, Agent or Law Firm David H. Hitt
  • Patent number: 4937720
    Abstract: This invention relates to a VSCF system for aircraft power generation having a DC source, the DC source producing a DC signal. An inverter is coupled to the DC source and produces a constant frequency AC signal from the DC signal. It is known that, in converting the DC signal to the AC signal, the inverter distorts the DC signal, producing harmonic content therein. Accordingly, an inverter controller is provided which analytically determines distortion of the DC signal due to inverter action and alters PWM patterns fed to the inverter to precompensate for harmonic content in the DC signal.
    Type: Grant
    Filed: October 13, 1989
    Date of Patent: June 26, 1990
    Assignee: Sundstrand Corporation
    Inventor: Maurice A. Kirchberg
  • Patent number: 4935859
    Abstract: This invention relates to a VSCF system for aircraft power generation having a DC source, the DC source producing a substantially constant voltage DC signal. An inverter is coupled to the DC source and receives the DC signal, applying a PWM pattern of switching transients to the DC signal to produce an AC signal from the DC signal. The subject invention contemplates the addition of a feedback circuit which comprises a transformer providing an inductive coupling between the AC signal at a point of regulation and the DC signal at a point between the DC source and the inverter to eliminate short duration switching transients in the PWM pattern. Modulation of the DC signal allows short duration switching transients in the PWM pattern to be lengthened, thereby avoiding physical minimum time switching limitations in the switches of the inverter. Feedback of the AC signal allows inverter frequency to be changed while maintaining synchronization between the DC signal modulation and PWM pattern fed to the inverter.
    Type: Grant
    Filed: October 13, 1989
    Date of Patent: June 19, 1990
    Assignee: Sundstrand Corporation
    Inventors: Maurice A. Kirchberg, Alexander Cook
  • Patent number: 4935842
    Abstract: A compact, lightweight, high current, feed-through capacitor for variable speed constant frequency aircraft power systems to provide filtering for unwanted higher harmonics and electromagnetic interference produced by the systems which provides a high temperature, high current feed-through capacitor having a hollow conductive housing, a conductive feed-through stud within the housing, an annular capacitive element for conducting electrical energy, and an electrical coupling, comprising a first conductor composed between an outer surface of the stud and an inner surface of the capacitive element, the first conductor providing an electrical path from the stud to the capacitive element for electrical energy present in the stud and a second conductor disposed radially between an outer surface of the capacitive element and an inner surface of the housing, the second conductor providing an electrical path for the electrical energy conducted by the capacitive element from the stud.
    Type: Grant
    Filed: July 12, 1989
    Date of Patent: June 19, 1990
    Assignee: Sundstrand Corporation
    Inventors: William E. Carlson, Mark W. Metzler, Lawrence E. Crowe
  • Patent number: 4935860
    Abstract: This invention relates to a VSCF system for aircraft power generation having a DC source, the DC source producing a substantially constant voltage DC signal. An inverter is coupled to the DC source and receives the DC signal, applying a PWM pattern of switching transients to the DC signal to produce an AC signal from the DC signal. The subject invention contemplates the addition of a DC link modulator comprising a ripple generator which varies the voltage of the DC signal to eliminate short duration switching transients in the PWM pattern. Variation of the DC signal allows short duration switching transients in the PWM pattern to be lengthened, thereby avoiding physical minimum time switching limitations in the switches of the inverter. In the preferred embodiment of the invention, an inverter controller provides a synchronizing signal to the ripple generator, which is coupled to a point between the DC source and the inverter.
    Type: Grant
    Filed: October 13, 1989
    Date of Patent: June 19, 1990
    Assignee: Sundstrand Corporation
    Inventors: Maurice A. Kirchberg, Alexander Cook
  • Patent number: 4930045
    Abstract: A disassemblable capacitor mount for large, high power, high temperature ceramic capacitors is disclosed. The capacitor mount allows the capacitors to be mechanically secured to a printed circuit board or other planar surface and allows for good electrical contact to be made with the capacitors to handle high power. The capacitor mount comprises a pair of substantially parallel, spaced-apart conductors, the conductors provided with a plurality of corresponding spaced-apart lateral slots on facing planar sides thereof. A plurality of compressible contactors are disposed within the slots. A plurality of capacitors having opposed electrode ends are disposed between the conductors, the ends positioned within the slots and contacting the contactors. Finally, a rigid mechanism removably fixes the conductors to a planar surface. The conductors compressingly urge against the capacitors.
    Type: Grant
    Filed: October 26, 1989
    Date of Patent: May 29, 1990
    Assignee: Sundstrand Corporation
    Inventors: William E. Carlson, Mark W. Metzler