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).
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Patent number: 6864667Abstract: 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: GrantFiled: January 18, 2001Date of Patent: March 8, 2005Assignee: Delphi Technologies, Inc.Inventors: Duane Joseph Buening, Ronald John Krefta
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Patent number: 6741060Abstract: 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: GrantFiled: April 5, 2001Date of Patent: May 25, 2004Assignee: Delphi Technologies, Inc.Inventors: Ronald John Krefta, James E. Walters, Fani S. Gunawan
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Patent number: 6639371Abstract: 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: GrantFiled: August 17, 2001Date of Patent: October 28, 2003Assignee: Delphi Technologies, Inc.Inventors: James E. Walters, Ronald John Krefta
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Patent number: 6577097Abstract: 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: GrantFiled: August 13, 2001Date of Patent: June 10, 2003Assignee: Delphi Technologies, Inc.Inventors: Ronald John Krefta, Tillasthanam V. Sriram
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Patent number: 6538358Abstract: 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: GrantFiled: August 28, 2000Date of Patent: March 25, 2003Assignee: Delphi Technologies, Inc.Inventors: Ronald John Krefta, Frederick B. Reiter, Jr.
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Publication number: 20030034748Abstract: 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: ApplicationFiled: August 17, 2001Publication date: February 20, 2003Inventors: James E. Walters, Ronald John Krefta
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Publication number: 20030034755Abstract: 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: ApplicationFiled: August 13, 2001Publication date: February 20, 2003Inventors: Ronald John Krefta, Tillasthanam V. Sriram
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Publication number: 20020145837Abstract: 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: ApplicationFiled: April 5, 2001Publication date: October 10, 2002Inventors: Ronald John Krefta, James E. Walters, Fani S. Gunawan
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Patent number: 6455978Abstract: 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: GrantFiled: August 28, 2000Date of Patent: September 24, 2002Assignee: Delphi Technologies, Inc.Inventors: Ronald John Krefta, Frederick B. Reiter, Jr.
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Patent number: 6437477Abstract: 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: GrantFiled: August 28, 2000Date of Patent: August 20, 2002Assignee: Delphi Technologies, Inc.Inventors: Ronald John Krefta, Frederick B. Reiter, Jr.
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Publication number: 20020093266Abstract: 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: ApplicationFiled: January 18, 2001Publication date: July 18, 2002Inventors: Duane Joseph Buening, Ronald John Krefta
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Patent number: 6342772Abstract: 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: GrantFiled: January 19, 2001Date of Patent: January 29, 2002Assignee: Delphi Technologies, Inc.Inventors: Gabriel Gallegos-Lopez, Ronald John Krefta
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Patent number: 6232739Abstract: 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: GrantFiled: February 11, 2000Date of Patent: May 15, 2001Assignee: Delphi Technologies, Inc.Inventors: Ronald John Krefta, James E. Walters