Patents by Inventor Ronald John Krefta

Ronald John Krefta 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: 6864667
    Abstract: An electrical generator having a stator, a rotor, two windings, and a rectifying circuit. The stator has a first winding arranged in a wye configuration and a second winding arranged in a delta configuration. The wye winding is wound in a full pitch pattern around three stator teeth while the delta winding is wound in a short pitch pattern around two stator teeth, or vice versa. The wye and delta windings are connected to a single bridge rectifying circuit.
    Type: Grant
    Filed: January 18, 2001
    Date of Patent: March 8, 2005
    Assignee: Delphi Technologies, Inc.
    Inventors: Duane Joseph Buening, Ronald John Krefta
  • Patent number: 6741060
    Abstract: Method and system for controlling a permanent magnet machine driven by an inverter is provided. The method allows for monitoring a signal indicative of a fault condition. The method further allows for generating during the fault condition a respective signal configured to maintain a field weakening current even though electrical power from an energy source is absent during said fault condition. The level of the maintained field-weakening current enables the machine to operate in a safe mode so that the inverter is protected from excess voltage.
    Type: Grant
    Filed: April 5, 2001
    Date of Patent: May 25, 2004
    Assignee: Delphi Technologies, Inc.
    Inventors: Ronald John Krefta, James E. Walters, Fani S. Gunawan
  • Patent number: 6639371
    Abstract: Method and system for controlling a permanent magnet machine are provided. The method provides a sensor assembly for sensing rotor sector position relative to a plurality of angular sectors. The method further provides a sensor for sensing angular increments in rotor position. The method allows starting the machine in a brushless direct current mode of operation using a calculated initial rotor position based on an initial angular sector position information from the sensor assembly. Upon determining a transition from the initial angular sector to the next angular sector, the method allows switching to a sinusoidal mode of operation using rotor position based on rotor position information from the incremental sensor.
    Type: Grant
    Filed: August 17, 2001
    Date of Patent: October 28, 2003
    Assignee: Delphi Technologies, Inc.
    Inventors: James E. Walters, Ronald John Krefta
  • Patent number: 6577097
    Abstract: Method and system for controlling a synchronous machine including a polyphase stator are provided. The machine may be used in a piece of equipment respectively as a generator and as a motor for starting an engine in the piece of equipment. The method allows to sense rotor position of the machine using a sensor assembly configured to supply a respective stream of pulses indicative of rotor position relative to each phase of the machine. The method further allows to process each stream of pulses from the sensor assembly to generate a first set of inverter control signals. The first set of inverter control signals is applied to an inverter circuit coupled to energize the phases of the stator to start the machine. The first set of control signals is configured to provide a first cycle-conduction angle relative to the zero-crossings of the respective phase EMF voltages of the machine to produce a sufficiently high level of torque during start of the machine.
    Type: Grant
    Filed: August 13, 2001
    Date of Patent: June 10, 2003
    Assignee: Delphi Technologies, Inc.
    Inventors: Ronald John Krefta, Tillasthanam V. Sriram
  • Patent number: 6538358
    Abstract: A hybrid electrical machine generator having a permanent magnetic rotor field in addition to an electrically excited rotor field is disclosed. The generator rotor (120) has a wound field coil (124) mounted on the rotor shaft (122) between two opposing claw segments (126, 128). One or more permanent magnets (130) maybe provided about the periphery of the first and/or second claw segments.
    Type: Grant
    Filed: August 28, 2000
    Date of Patent: March 25, 2003
    Assignee: Delphi Technologies, Inc.
    Inventors: Ronald John Krefta, Frederick B. Reiter, Jr.
  • Publication number: 20030034755
    Abstract: Method and system for controlling a synchronous machine including a polyphase stator are provided. The machine may be used in a piece of equipment respectively as a generator and as a motor for starting an engine in the piece of equipment. The method allows to sense rotor position of the machine using a sensor assembly configured to supply a respective stream of pulses indicative of rotor position relative to each phase of the machine. The method further allows to process each stream of pulses from the sensor assembly to generate a first set of inverter control signals. The first set of inverter control signals is applied to an inverter circuit coupled to energize the phases of the stator to start the machine. The first set of control signals is configured to provide a first cycle-conduction angle relative to the zero-crossings of the respective phase EMF voltages of the machine to produce a sufficiently high level of torque during start of the machine.
    Type: Application
    Filed: August 13, 2001
    Publication date: February 20, 2003
    Inventors: Ronald John Krefta, Tillasthanam V. Sriram
  • Publication number: 20030034748
    Abstract: Method and system for controlling a permanent magnet machine are provided. The method provides a sensor assembly for sensing rotor sector position relative to a plurality of angular sectors. The method further provides a sensor for sensing angular increments in rotor position. The method allows starting the machine in a brushless direct current mode of operation using a calculated initial rotor position based on an initial angular sector position information from the sensor assembly. Upon determining a transition from the initial angular sector to the next angular sector, the method allows switching to a sinusoidal mode of operation using rotor position based on rotor position information from the incremental sensor.
    Type: Application
    Filed: August 17, 2001
    Publication date: February 20, 2003
    Inventors: James E. Walters, Ronald John Krefta
  • Publication number: 20020145837
    Abstract: Method and system for controlling a permanent magnet machine driven by an inverter is provided. The method allows for monitoring a signal indicative of a fault condition. The method further allows for generating during the fault condition a respective signal configured to maintain a field weakening current even though electrical power from an energy source is absent during said fault condition. The level of the maintained field-weakening current enables the machine to operate in a safe mode so that the inverter is protected from excess voltage.
    Type: Application
    Filed: April 5, 2001
    Publication date: October 10, 2002
    Inventors: Ronald John Krefta, James E. Walters, Fani S. Gunawan
  • Patent number: 6455978
    Abstract: A hybrid electrical machine having a permanent magnetic rotor field in addition to an electrically excited rotor field is disclosed. The generator rotor (220) has two opposing claw segments (226, 228) mounted at opposite ends of a rotor shaft (222). A third, center claw segment (232) is mounted on the rotor shaft between the first and second claw segments. A first wound field coil (224) is mounted on the rotor shaft between the first and third claw segments, and a second wound field coil (234) is mounted between the second and third claw segments. One or more permanent magnets (230, 231) may be provided about the periphery of the first, second, and/or third claw segments.
    Type: Grant
    Filed: August 28, 2000
    Date of Patent: September 24, 2002
    Assignee: Delphi Technologies, Inc.
    Inventors: Ronald John Krefta, Frederick B. Reiter, Jr.
  • Patent number: 6437477
    Abstract: A hybrid electrical machine having a permanent magnetic rotor field in addition to an electrically excited rotor field is disclosed. The generator rotor (320) has a first claw segment (326) and a second claw segment (328) mounted at opposite ends of a rotor shaft (322). A third, center claw segment (332) is mounted on the rotor shaft, between the first and second claw segments. A wound field coil (324) is mounted on the rotor shaft (322) between the first and third claw segments, and a permanent, axial flux magnet (336) is mounted on the rotor shaft between the second claw segment and the third claw segment. In some embodiments, one or more permanent magnets may be provided about the periphery of the first, second, and/or third claw segments.
    Type: Grant
    Filed: August 28, 2000
    Date of Patent: August 20, 2002
    Assignee: Delphi Technologies, Inc.
    Inventors: Ronald John Krefta, Frederick B. Reiter, Jr.
  • Publication number: 20020093266
    Abstract: An electrical generator having a stator, a rotor, two windings, and a rectifying circuit. The stator has a first winding arranged in a wye configuration and a second winding arranged in a delta configuration. The wye winding is wound in a full pitch pattern around three stator teeth while the delta winding is wound in a short pitch pattern around two stator teeth, or vice versa. The wye and delta windings are connected to a single bridge rectifying circuit.
    Type: Application
    Filed: January 18, 2001
    Publication date: July 18, 2002
    Inventors: Duane Joseph Buening, Ronald John Krefta
  • Patent number: 6342772
    Abstract: Drive circuit and method for driving a switched reluctance machine having at least two winding per pole are provided. The circuit includes first and second direct current links. The circuit further includes a first winding having first and second terminals. The first winding is connectable across said first and second links. A first switch is coupled across the first link and the first terminal of the first winding. A second switch is coupled across the second terminal of the first winding and the second link. A second winding is connectable in series circuit to that first winding. The second winding has first and second terminals. A third switch is coupled across one of the first and second links and the second terminal of the second winding.
    Type: Grant
    Filed: January 19, 2001
    Date of Patent: January 29, 2002
    Assignee: Delphi Technologies, Inc.
    Inventors: Gabriel Gallegos-Lopez, Ronald John Krefta
  • Patent number: 6232739
    Abstract: An apparatus for determining an incremental angular position of a rotating member of an induction motor. A sensor assembly is positioned adjacent a target wheel attached to the rotating member, the target wheel having a plurality of teeth, separated by slots, angularly spaced around the periphery of the target wheel. The sensor assembly is located proximate the periphery of the target wheel, and includes a plurality of sensors each configured to generate a respective output signal that transitions between first and second states at the passage thereby of each leading and trailing edge of the teeth. The apparatus also includes a processing circuit configured to generate an incremental position signal in response to the output signals. Each sensor is spaced from an adjacent sensor by a predetermined distance equal to 180 degrees divided by n, where n is the number of sensors, and 360 degrees is a tooth-to-tooth distance.
    Type: Grant
    Filed: February 11, 2000
    Date of Patent: May 15, 2001
    Assignee: Delphi Technologies, Inc.
    Inventors: Ronald John Krefta, James E. Walters