Patents by Inventor Douglas C. Folts

Douglas C. Folts 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).

  • Publication number: 20100019776
    Abstract: The present disclosure relates to a system and method for analyzing a superconducting wire. A method in accordance with at least one embodiment described herein may include performing a voltage/current (VI) test for each of a plurality of portions of superconducting wire. The VI test may include determining a plurality of VI data points for each of the plurality of portions of superconducting wire at a first VI datapoint of about (Ic (critical current), Ec (critical electric field)) and at a second VI datapoint of about (Ix, Ex). Ex may be at least 10 times Ec and Ix may be approximately equal to the current resulting at that voltage drop. The method may further include analyzing the plurality of VI data points for each portion of superconducting wire to determine if one or more of the portions of superconducting wire are defective. Of course, numerous other embodiments are also within the scope of the present disclosure.
    Type: Application
    Filed: July 23, 2008
    Publication date: January 28, 2010
    Inventors: Douglas C. Folts, Eric R. Podtburg, Robert C. Diehl
  • Publication number: 20100002475
    Abstract: A system for connecting a wind turbine generator to a utility power network includes a first power converter that converts an AC signal from the wind turbine generator to a DC signal and supplies a controlled amount of reactive current to the wind turbine generator. The system also includes a second power converter, connected in series with the first converter, which converts the DC signal from the first power converter to a line-side AC signal and supplies a controlled amount of current to the utility power network. A power dissipation element is coupled to the first and second power converters for dissipating power from the first power converter.
    Type: Application
    Filed: July 1, 2008
    Publication date: January 7, 2010
    Applicant: American Superconductor Corporation
    Inventors: Douglas C. Folts, David J. Gritter, Michael P. Ross
  • Patent number: 7567160
    Abstract: A reactive power compensation system includes a reactive power compensation device and a transformer electrically connected to the reactive power compensation device and having a cooling unit. The reactive power compensation device has an enclosure housing power electronics and at least one fan which provides an airflow for cooling the power electronics. The enclosure further includes an air outlet through which the airflow exits the enclosure after cooling the power electronics. The air outlet and the airflow are directed toward the cooling unit of the transformer to provide supplementary cooling to the transformer. The transformer cooling unit comprises external cooling fins in a liquid-filled transformer embodiment and comprises an air inlet of the transformer housing in a dry-type transformer embodiment. An optional duct may be provided between the enclosure and the transformer cooling unit.
    Type: Grant
    Filed: February 15, 2006
    Date of Patent: July 28, 2009
    Assignee: American Superconductor Corporation
    Inventors: Douglas C. Folts, Gary J. Bowers
  • Publication number: 20080194411
    Abstract: A cryogenically-cooled HTS wire includes a stabilizer having a total thickness in a range of 200-600 micrometers and a resistivity in a range of 0.8-15.0 microOhm cm at approximately 90 K. A first HTS layer is thermally-coupled to at least a portion of the stabilizer.
    Type: Application
    Filed: March 20, 2007
    Publication date: August 14, 2008
    Inventors: Douglas C. Folts, James MaGuire, Jie Yuan, Alexis P. Malozemoff
  • Publication number: 20080190646
    Abstract: A superconducting electrical cable system is configured to be included within a utility power grid having a known fault current level. The superconducting electrical cable system includes a non-superconducting electrical path interconnected between a first node and a second node of the utility power grid. A superconducting electrical path is interconnected between the first node and the second node of the utility power grid. The superconducting electrical path and the non-superconducting electrical path are electrically connected in parallel, and the superconducting electrical path has a lower series impedance than the non-superconducting electrical path when the superconducting electrical path is operated below a critical current level and a critical temperature.
    Type: Application
    Filed: March 20, 2007
    Publication date: August 14, 2008
    Inventors: DOUGLAS C. FOLTS, James Maguire, Jie Yuan, Alexis P. Malozemoff
  • Publication number: 20080190637
    Abstract: A cryogenically-cooled HTS cable is configured to be included within a utility power grid having a maximum fault current that would occur in the absence of the cryogenically-cooled HTS cable. The cryogenically-cooled HTS cable includes a continuous liquid cryogen coolant path for circulating a liquid cryogen. A continuously flexible arrangement of HTS wires has an impedance characteristic that attenuates the maximum fault current by at least 10%. The continuously flexible arrangement of HTS wires is configured to allow the cryogenically-cooled HTS cable to operate, during the occurrence of a maximum fault condition, with a maximum temperature rise within the HTS wires that is low enough to prevent the formation of gas bubbles within the liquid cryogen.
    Type: Application
    Filed: March 20, 2007
    Publication date: August 14, 2008
    Inventors: DOUGLAS C. FOLTS, James Maguire, Jie Yuan, Alexis P. Malozemoff
  • Publication number: 20080192392
    Abstract: A superconducting transformer system is configured to be included within a utility power grid having a known fault current level. The superconducting transformer system includes a non-superconducting transformer interconnected between a first node and a second node of the utility power grid. A superconducting transformer is interconnected between the first node and the second node of the utility power grid. The superconducting transformer and the non-superconducting transformer are electrically connected in parallel. The superconducting transformer has a lower series impedance than the non-superconducting transformer when the superconducting transformer is operated below a critical current level and a critical temperature. The superconducting transformer is configured to have a series impedance that is at least N times the series impedance of the non-superconducting transformer when the superconducting transformer is operated at or above one or more of the critical current level and the critical temperature.
    Type: Application
    Filed: March 20, 2007
    Publication date: August 14, 2008
    Inventors: DOUGLAS C. FOLTS, JAMES MAGUIRE, JIE YUAN, ALEXIS P. MALOZEMOFF
  • Publication number: 20080191561
    Abstract: A superconducting electrical cable system is configured to be included within a utility power grid. The superconducting electrical cable system includes a superconducting electrical path interconnected between a first and a second node within the utility power grid. A non-superconducting electrical path is interconnected between the first and second nodes within the utility power grid. The superconducting electrical path and the non-superconducting electrical path are electrically connected in parallel. The superconducting electrical path has a lower series impedance, when operated below a critical current level, than the non-superconducting electrical path. The superconducting electrical path has a higher series impedance, when operated at or above the critical current level, than the non-superconductor electrical path.
    Type: Application
    Filed: February 9, 2007
    Publication date: August 14, 2008
    Inventors: DOUGLAS C. FOLTS, James Maguire, Jie Yuan, Alexis P. Malozemoff
  • Patent number: 7265521
    Abstract: The invention features a system and approach for minimizing the step voltage change as seen by the utility customer as well minimizing transients imposed on the fundamental waveform of a normal voltage carried on a utility power network when a reactive power source (e.g., capacitor bank) is instantaneously connected to the utility power. The reactive power source is adapted to transfer reactive power of a first polarity (e.g., capacitive reactive power) to the utility power network. The system includes a reactive power compensation device configured to transfer a variable quantity of reactive power of a second, opposite polarity to the utility power network, and a controller which, in response to the need to connect the shunt reactive power source to the utility power network, activates the reactive power compensation device and, substantially simultaneously, causes the shunt reactive power source to be connected to the utility power.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: September 4, 2007
    Assignee: American Superconductor Corporation
    Inventors: Arnold P. Kehrli, John A. Diaz De Leon, II, Douglas C. Folts
  • Patent number: 7091703
    Abstract: The invention features a system for connection to a utility power network. The system includes a reactive power compensation device coupled to the network and configured to transfer reactive power between the utility power network and the reactive power compensation device; a capacitor system configured to transfer capacitive reactive power between the utility power network and the capacitor system; an electro-mechanical switch for connecting and disconnecting the capacitor system to the utility power network; an interface associated with the electro-mechanical switch; a controller configured to provide control signals for controlling the electro-mechanical switch; and a communication channel for coupling the controller to the interface associated with the electro-mechanical switch.
    Type: Grant
    Filed: March 4, 2004
    Date of Patent: August 15, 2006
    Assignee: American Superconductor Corporation
    Inventors: Douglas C. Folts, William A. Vareka, Arnold P. Kehrli, John A. Diaz De Leon, II
  • Patent number: 6987331
    Abstract: A voltage recovery device is configured to provide reactive power to a utility power network at a level and for a duration sufficient to recover the voltage on the utility power network within a predetermined proportion of the nominal voltage, following a fault condition detected on the utility power network. In operation, the voltage recovery device reduces the overall transmission losses in a utility power system.
    Type: Grant
    Filed: August 31, 2001
    Date of Patent: January 17, 2006
    Assignee: American Superconductor Corporation
    Inventors: Paul Frederick Koeppe, Arnold P. Kehrli, Donald L. Brown, Warren Elliott Buckles, John A. Diaz De Leon, III, Douglas C. Folts
  • Patent number: 6906434
    Abstract: a voltage recovery device is configured to provide real and reactive power to a utility power network at a sufficient level and for a sufficient duration to recover the voltage on the utility power network within a predetermined proportion of the nominal voltage, following a fault condition detected on the utility power network. Moreover, the voltage recovery device reduces the overall transmission losses in a utility power system.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: June 14, 2005
    Assignee: American Superconductor Corporation
    Inventors: Paul Frederick Koeppe, Arnold P. Kehrli, John A. Diaz De Leon, II, Donald L. Brown, Warren Elliott Buckles, Douglas C. Folts
  • Patent number: 6900619
    Abstract: The invention features a system and approach for minimizing the step voltage change as seen by the utility customer as well minimizing transients imposed on the fundamental waveform of a normal voltage carried on a utility power network when a reactive power source (e.g., capacitor bank) is instantaneously connected to the utility power. The reactive power source is adapted to transfer reactive power of a first polarity (e.g., capacitive reactive power) to the utility power network. The system includes a reactive power compensation device configured to transfer a variable quantity of reactive power of a second, opposite polarity to the utility power network, and a controller which, in response to the need to connect the shunt reactive power source to the utility power network, activates the reactive power compensation device and, substantially simultaneously, causes the shunt reactive power source to be connected to the utility power.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: May 31, 2005
    Assignee: American Superconductor Corporation
    Inventors: Arnold P. Kehrli, John A. Diaz De Leon, II, Douglas C. Folts
  • Patent number: 6600973
    Abstract: Power is provided from an energy storage device to a utility network based on a detected condition, such as a fault, in the network. Specifically, it is determined whether a fault on the utility network is a near fault or a far fault relative to the energy storage device. Whether a fault is classified as “near” or “far” is determined based on a voltage drop in the utility network. Power is then supplied to the utility network based on whether the fault is a near fault or a far fault.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: July 29, 2003
    Assignee: American Supercondutor Corporation
    Inventors: Douglas C. Folts, Thomas Gregory Hubert
  • Patent number: 6577108
    Abstract: Power compensation is provided from a power compensation device to a utility power network carrying a nominal voltage. The power compensation device has a steady-state power delivery characteristic. The power compensation is provided by detecting a change of a predetermined magnitude in the nominal voltage on the utility power network and controlling the power compensation device to deliver, for a first period of time and in response to the detected change in the nominal voltage, reactive power to the utility power network. The power compensation device is controlled to deliver, for a second period of time following the first period of time, reactive power to the utility power network at a level that is a factor N(N>1) greater than the steady-state power delivery characteristic of the power compensation device.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: June 10, 2003
    Assignee: American Superconductor Corporation
    Inventors: Thomas Gregory Hubert, Douglas C. Folts, Warren Elliott Buckles
  • Publication number: 20030067285
    Abstract: The invention features a system and approach for minimizing the step voltage change as seen by the utility customer as well minimizing transients imposed on the fundamental waveform of a normal voltage carried on a utility power network when a reactive power source (e.g., capacitor bank) is instantaneously connected to the utility power. The reactive power source is adapted to transfer reactive power of a first polarity (e.g., capacitive reactive power) to the utility power network. The system includes a reactive power compensation device configured to transfer a variable quantity of reactive power of a second, opposite polarity to the utility power network, and a controller which, in response to the need to connect the shunt reactive power source to the utility power network, activates the reactive power compensation device and, substantially simultaneously, causes the shunt reactive power source to be connected to the utility power.
    Type: Application
    Filed: November 24, 1999
    Publication date: April 10, 2003
    Inventors: Arnold P. Kehrli, John A. Diaz De Leon, II, Douglas C. Folts
  • Publication number: 20030026114
    Abstract: Power compensation is provided from a power compensation device to a utility power network carrying a nominal voltage. The power compensation device has a steady-state power delivery characteristic. The power compensation is provided by detecting a change of a predetermined magnitude in the nominal voltage on the utility power network and controlling the power compensation device to deliver, for a first period of time and in response to the detected change in the nominal voltage, reactive power to the utility power network. The power compensation device is controlled to deliver, for a second period of time following the first period of time, reactive power to the utility power network at a level that is a factor N(N>1) greater than the steady-state power delivery characteristic of the power compensation device.
    Type: Application
    Filed: July 15, 2002
    Publication date: February 6, 2003
    Applicant: American Superconductor Corporation a Delaware corporation
    Inventors: Thomas Gregory Hubert, Douglas C. Folts, Warren Elliott Buckles
  • Patent number: 6445555
    Abstract: Circuitry detects a quench in a superconducting magnet and discharges the superconducting magnet into a load, such as a utility system, at a substantially constant voltage. The circuitry can be an inverter, arranged between the superconducting magnet and the load, which may operate in overload mode during discharge. Discharging occurs until the amount of energy in the superconducting magnet is below a predetermined level.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: September 3, 2002
    Assignee: American Superconductor Corporation
    Inventors: Warren Elliott Buckles, Douglas C. Folts
  • Publication number: 20020105231
    Abstract: A voltage recovery device is configured to provide reactive power to a utility power network at a level and for a duration sufficient to recover the voltage on the utility power network within a predetermined proportion of the nominal voltage, following a fault condition detected on the utility power network. In operation, the voltage recovery device reduces the overall transmission losses in a utility power system.
    Type: Application
    Filed: August 31, 2001
    Publication date: August 8, 2002
    Inventors: Paul Frederick Koeppe, Arnold P. Kehrli, Donald L. Brown, Warren Elliott Buckles, John A. Diaz De Leon, Douglas C. Folts
  • Patent number: 6414853
    Abstract: A transfer of power between an energy storage device and a load is controlled by obtaining a DC voltage from the energy storage device, and controlling a phase angle of AC power delivered to the load to keep the DC voltage substantially constant. The phase angle of the AC power is controlled by controlling a current component of the AC power.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: July 2, 2002
    Assignee: American Superconductor Corporation
    Inventors: Warren Elliott Buckles, Douglas C. Folts