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.

Abstract: A composite substrate for superconductors and methods for making the same are described. The composite substrate of the present invention includes at least a core layer having and a sheath layer having a cube texture on at least a portion its surface. In certain embodiments, the core layer can include a nickel-tungsten-molybdenum alloy having about 2-10 atomic percent tungsten and 2-15 atomic percent molybdenum. In some embodiments, the sheath layer can include nickel or a nickel-tungsten alloy having about 0 to 6 atomic percent tungsten. Generally, the core layer is stronger than the sheath layer and an interdiffusion zone can exist between the core layer and the sheath layer.

Abstract: In a general aspect, a power conversion system includes a power converter, a transformer, and a voltage adjustment device. The power converter is configured to receive a variable DC power generated by a power generation device and to convert the received DC power to AC power at a first voltage. The transformer is configured to receive the AC power from the power converter and to deliver AC power at a second voltage to a utility power network. The voltage adjustment device is configured to adjust the first voltage to a target value determined on the basis of a voltage of the DC power.

Abstract: A power plant for providing electric power to a power grid includes energy sources; power conditioning units and a controller configured to cause power provided to the grid to have selected electrical characteristics. The controller is in high speed real-time communication with the power conditioning units and programmed to provide instructions to the power conditioning units.

Abstract: Under one aspect, a laminated, spliced superconductor wire includes a superconductor joint, which includes (i) first and second superconductor wires, each wire including a substrate, a superconductor layer overlying the substrate, and a cap layer overlying the superconductor layer; and (ii) a conductive bridge, the conductive bridge including a substrate, a superconductor layer overlying the substrate, and a cap layer overlying the superconductor layer, wherein the cap layer of the conductive bridge is in electrically conductive contact with a portion of the cap layer of each of the first and second superconductor wires through an electrically conductive bonding material. The spliced wire also includes (b) a stabilizer structure surrounding at least a portion of the superconductor joint, wherein the superconductor joint is in electrical contact with the stabilizer structure; and (c) a substantially nonporous electrically conductive filler, wherein the filler substantially surrounds the superconductor joint.

Abstract: A method for providing electric power to a power system includes receiving, at a slave node of a power converter having a plurality of slave nodes, a first synchronization signal via a first communication channel, the first synchronization signal purporting to represent a master timing characteristic of a master control node of the converter; receiving, at the slave node of the converter, a second synchronization signal via a second communication channel, the second synchronization signal purporting to represent a master timing characteristic of the master control node of the converter; synchronizing an internal timing characteristic of the slave control node with the master timing characteristic of the master control node using the first synchronization signal; determining that the first synchronization signal is invalid; and synchronizing an internal timing characteristic of the slave control node with the master timing characteristic of the master control node using the second synchronization signal.

Abstract: High-current, compact, flexible conductors containing high temperature superconducting (HTS) tapes and methods for making the same are described. The HTS tapes are arranged into a stack, a plurality of stacks are arranged to form a superstructure, and the superstructure is twisted about the cable axis to obtain a HTS cable. The HTS cables of the invention can be utilized in numerous applications such as cables employed to generate magnetic fields for degaussing and high current electric power transmission or distribution applications.

Abstract: A stator assembly for use in a superconducting generator operated at frequencies up to 10 Hz is disclosed. The stator assembly includes a ferromagnetic stator winding support having a plurality of teeth defining slots, the slots configured to receive and support stator windings. The stator winding support is formed so that the ratio of the sum of the widths of the slots to the sum of the widths of the teeth and slots is in the range of 0.65 to 0.90.

Abstract: A direct-drive power train of a wind power plant is protected from over-torque by a torque limiting device. The power train includes a turbine rotor including a hub and blades supported on the hub, and a generator including a stator and a generator rotor rotatably disposed within the stator. The generator rotor includes a generator rotor body, a rotor shaft, and the torque limiting device connects the generator rotor body to the rotor shaft. The torque limiting device is configured to support the generator rotor body within the stator and allow coaxial rotation of the rotor body relative to the stator. The hub and the generator rotor are connected by the rotor shaft, and the rotor shaft rotates at the same frequency as the hub.

Abstract: An article including a substrate and a layer of a homogeneous metal-oxyfluoride intermediate film disposed on the substrate, the intermediate film containing a rare earth metal, an alkaline earth metal, and a transition metal. The intermediate film has a defect density less than 20 percent and, upon thermal treatment, is capable of converting to a homogeneous rare earth metal-alkaline earth metal-transition metal-oxide superconductor film with a stoichiometric thickness greater than 1 ?m and up to 5 ?m. Also disclosed is another article including a substrate and the homogeneous superconductor film with a stoichiometric thickness greater than 1 ?m and up to 5 ?m. Further, methods of making these two articles are described.

Abstract: A method of controlling a static VAR compensator includes providing a static VAR compensator having a reactive component and a thyristor for switching the reactive component into and out of a power distribution network; monitoring a periodic waveform on the power distribution network and controlling operation of the thyristor on the basis of the harmonic frequency content of the waveform.

Abstract: Under one aspect, a laminated, spliced superconductor wire includes a superconductor joint, which includes (i) first and second superconductor wires, each wire including a substrate, a superconductor layer overlying the substrate, and a cap layer overlying the superconductor layer; and (ii) a conductive bridge, the conductive bridge including a substrate, a superconductor layer overlying the substrate, and a cap layer overlying the superconductor layer, wherein the cap layer of the conductive bridge is in electrically conductive contact with a portion of the cap layer of each of the first and second superconductor wires through an electrically conductive bonding material. The spliced wire also includes (b) a stabilizer structure surrounding at least a portion of the superconductor joint, wherein the superconductor joint is in electrical contact with the stabilizer structure; and (c) a substantially nonporous electrically conductive filler, wherein the filler substantially surrounds the superconductor joint.

Abstract: In a general aspect, a power conversion system includes a power converter, a transformer, and a voltage adjustment device. The power converter is configured to receive a variable DC power generated by a power generation device and to convert the received DC power to AC power at a first voltage. The transformer is configured to receive the AC power from the power converter and to deliver AC power at a second voltage to a utility power network. The voltage adjustment device is configured to adjust the first voltage to a target value determined on the basis of a voltage of the DC power.

Abstract: The present disclosure generally relates to a superconducting power grid having one or more AC/DC converters. The superconducting grid may further include one or more pairs of superconducting DC cables connecting each AC/DC converter. Each pair of superconducting DC cables may include a first positive polarity cable and a first negative polarity cable. The grid may also include at least one switching device configured to operatively connect at least one of the first and second AC/DC converters with at least one of the pairs of superconducting DC cables, the switching device further configured to adjust the polarity of at least one of the polarity cables. Other embodiments and implementations are also within the scope of the present disclosure.

Abstract: A direct-drive power train of a wind power plant is disclosed. The power train includes a turbine rotor including a hub and blades supported on the hub, and a generator including a stator and a generator rotor rotatably disposed within the stator. The generator rotor includes a generator rotor body, a rotor shaft, and a torque limiting device connecting the generator rotor body to the rotor shaft. The torque limiting device is configured to support the generator rotor body within the stator and allow coaxial rotation of the rotor body relative to the stator. The hub and the generator rotor are connected by the rotor shaft, and the rotor shaft rotates at the same frequency as the hub.

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.

Abstract: A power electronic assembly includes a pair of thermally and electrically conductive plates, and semiconductor switching elements positioned between contact surfaces of the pair of conductive plates. A first of the semiconductor switching elements is positioned at a first region of the conductive plates, and a second of the semiconductor switching elements positioned at a second region of the conductive plates. At least one of the conductive plates includes an aperture positioned between the first region and the second region of the conductive plates, such that in a compressed state, a contact surface of the conductive plate associated with the first region is substantially parallel to and offset from that of the second region in a direction parallel to the direction of compression.

Abstract: Superconductor precursor solutions are disclosed. The precursor solutions contain, for example, a salt of a rare earth metal, a salt of an alkaline earth metal and a salt of a transition metal. The precursor solutions can optionally include a Lewis base. The precursor solutions can be processed relatively quickly to provide a relatively thick and good quality intermediate of a rare earth metal-alkaline earth metal-transition metal oxide.

Abstract: A system for providing reactive power compensation to a utility power network includes a switch coupled to the utility power network, and a capacitor coupled with the switch for providing a controlled amount of reactive current based on conditions of the utility power network. The system also includes a switchable power dissipation device coupled in series to the capacitor and configured to provide a preselected amount of impedance to the reactive current for a predetermined duration when a line voltage on the utility power network drops below a threshold.

Abstract: An apparatus for power conversion includes an inverter; a converter configurable to function as a DC voltage booster; and a controller for selectively causing the converter to provide a boosted DC voltage to the inverter.