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).
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Publication number: 20100019776Abstract: 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: ApplicationFiled: July 23, 2008Publication date: January 28, 2010Inventors: Douglas C. Folts, Eric R. Podtburg, Robert C. Diehl
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Publication number: 20100002475Abstract: 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: ApplicationFiled: July 1, 2008Publication date: January 7, 2010Applicant: American Superconductor CorporationInventors: Douglas C. Folts, David J. Gritter, Michael P. Ross
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Patent number: 7567160Abstract: 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: GrantFiled: February 15, 2006Date of Patent: July 28, 2009Assignee: American Superconductor CorporationInventors: Douglas C. Folts, Gary J. Bowers
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Publication number: 20080194411Abstract: 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: ApplicationFiled: March 20, 2007Publication date: August 14, 2008Inventors: Douglas C. Folts, James MaGuire, Jie Yuan, Alexis P. Malozemoff
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Publication number: 20080190646Abstract: 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: ApplicationFiled: March 20, 2007Publication date: August 14, 2008Inventors: DOUGLAS C. FOLTS, James Maguire, Jie Yuan, Alexis P. Malozemoff
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Publication number: 20080190637Abstract: 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: ApplicationFiled: March 20, 2007Publication date: August 14, 2008Inventors: DOUGLAS C. FOLTS, James Maguire, Jie Yuan, Alexis P. Malozemoff
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Publication number: 20080192392Abstract: 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: ApplicationFiled: March 20, 2007Publication date: August 14, 2008Inventors: DOUGLAS C. FOLTS, JAMES MAGUIRE, JIE YUAN, ALEXIS P. MALOZEMOFF
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Publication number: 20080191561Abstract: 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: ApplicationFiled: February 9, 2007Publication date: August 14, 2008Inventors: DOUGLAS C. FOLTS, James Maguire, Jie Yuan, Alexis P. Malozemoff
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Patent number: 7265521Abstract: 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: GrantFiled: May 24, 2005Date of Patent: September 4, 2007Assignee: American Superconductor CorporationInventors: Arnold P. Kehrli, John A. Diaz De Leon, II, Douglas C. Folts
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Patent number: 7091703Abstract: 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: GrantFiled: March 4, 2004Date of Patent: August 15, 2006Assignee: American Superconductor CorporationInventors: Douglas C. Folts, William A. Vareka, Arnold P. Kehrli, John A. Diaz De Leon, II
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Patent number: 6987331Abstract: 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: GrantFiled: August 31, 2001Date of Patent: January 17, 2006Assignee: American Superconductor CorporationInventors: Paul Frederick Koeppe, Arnold P. Kehrli, Donald L. Brown, Warren Elliott Buckles, John A. Diaz De Leon, III, Douglas C. Folts
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Patent number: 6906434Abstract: 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: GrantFiled: November 24, 1999Date of Patent: June 14, 2005Assignee: American Superconductor CorporationInventors: Paul Frederick Koeppe, Arnold P. Kehrli, John A. Diaz De Leon, II, Donald L. Brown, Warren Elliott Buckles, Douglas C. Folts
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Patent number: 6900619Abstract: 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: GrantFiled: November 24, 1999Date of Patent: May 31, 2005Assignee: American Superconductor CorporationInventors: Arnold P. Kehrli, John A. Diaz De Leon, II, Douglas C. Folts
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Patent number: 6600973Abstract: 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: GrantFiled: November 24, 1999Date of Patent: July 29, 2003Assignee: American Supercondutor CorporationInventors: Douglas C. Folts, Thomas Gregory Hubert
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Patent number: 6577108Abstract: 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: GrantFiled: July 15, 2002Date of Patent: June 10, 2003Assignee: American Superconductor CorporationInventors: Thomas Gregory Hubert, Douglas C. Folts, Warren Elliott Buckles
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Publication number: 20030067285Abstract: 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: ApplicationFiled: November 24, 1999Publication date: April 10, 2003Inventors: Arnold P. Kehrli, John A. Diaz De Leon, II, Douglas C. Folts
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Publication number: 20030026114Abstract: 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: ApplicationFiled: July 15, 2002Publication date: February 6, 2003Applicant: American Superconductor Corporation a Delaware corporationInventors: Thomas Gregory Hubert, Douglas C. Folts, Warren Elliott Buckles
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Patent number: 6445555Abstract: 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: GrantFiled: November 24, 1999Date of Patent: September 3, 2002Assignee: American Superconductor CorporationInventors: Warren Elliott Buckles, Douglas C. Folts
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Publication number: 20020105231Abstract: 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: ApplicationFiled: August 31, 2001Publication date: August 8, 2002Inventors: Paul Frederick Koeppe, Arnold P. Kehrli, Donald L. Brown, Warren Elliott Buckles, John A. Diaz De Leon, Douglas C. Folts
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Patent number: 6414853Abstract: 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: GrantFiled: November 24, 1999Date of Patent: July 2, 2002Assignee: American Superconductor CorporationInventors: Warren Elliott Buckles, Douglas C. Folts