Showing papers in "IEEE Transactions on Applied Superconductivity in 2011"

HTS Pancake Coils Without Turn-to-Turn Insulation

Abstract: This paper reports a study of HTS pancake coils without turn-to-turn insulation. Three no-insulation (NI) pancake coils were wound: each single and double pancake coil of Bi2223 conductor and one single pancake of ReBCO conductor. An equivalent electrical circuit for modeling NI coils was verified by two sets of test: 1) charge-discharge; and 2) sudden discharge. Also, an overcurrent test in which a current exceeding a coil's critical current by 2.3 times was performed, and analysed, to demonstrate that in terms of stability NI HTS coils outperform their counterparts. The new NI winding offers HTS coils enhanced performance in three key parameters: overall current density; thermal stability; and mechanical integrity.

Energy-Efficient Single Flux Quantum Technology

Abstract: Figures of merit connecting processing capabilities with power dissipated (OpS/Watt, Joule/bit, etc.) are becoming dominant factors in choosing technologies for implementing the next generation of computing and communication network systems. Superconductivity is viewed as a technology capable of achieving higher energy efficiencies than other technologies. Static power dissipation of standard RSFQ logic, associated with dc bias resistors, is responsible for most of the circuit power dissipation. In this paper, we review and compare different superconductor digital technology approaches and logic families addressing this problem. We present a novel energy-efficient single flux quantum logic family, ERSFQ/eSFQ. We also discuss energy-efficient approaches for output data interface and overall cryosystem design.

Zero Static Power Dissipation Biasing of RSFQ Circuits

Abstract: We present a novel, resistor-free approach to dc biasing of RSFQ circuits, known as Energy-efficient RSFQ (ERSFQ). This biasing scheme does not dissipate energy in the static (non-active) mode, and dissipates orders of magnitude less power than traditional RSFQ while operating. Using this approach, we have designed, fabricated and successfully tested at low and high speed a D flip-flop with complementary outputs and several static frequency dividers. We present the method, demonstrate experimental results, and discuss future implementations of ERSFQ.

10 MW Class Superconductor Wind Turbine Generators

Abstract: High temperature superconductor (HTS) technology enables generators with one third the weight and one half the losses of conventional machines. These technologies enable a significant reduction in the size and weight of 10 MW-class generators for direct-drive wind turbine systems and reduce the cost of clean energy relative to conventional copper and permanent-magnet-based generators and gearboxes. With compact and light-weight 10 MW-class HTS generators, installation and low maintenance operation of high power wind turbine systems becomes practical and enable cost-effective access to wind resources. Under a program funded by the NIST-Advanced Technology Program, key generator technologies for a 10 MW class generator have been developed. This paper summarizes work under the NIST and internal programs.

Full Power Test of a 36.5 MW HTS Propulsion Motor

Abstract: This paper discusses the full-power testing of a 36.5 MW High Temperature Superconductor (HTS) propulsion motor at the Navy's Land Based Test Site (LBTS) located in Philadelphia, PA. This motor was developed under funding from the Office of Naval Research and passed no-load factory testing at Philadelphia in March 2007. The Naval Surface Warfare Center (Carderock Division - Philadelphia site) designed and installed a test facility at LBTS to support full-power/full-torque testing of the HTS motor delivered to the Navy in 2007. The facility, test plan and full-power and full-torque test results of the HTS propulsion motor are presented. These test results provide the final substantiation that this technology is ready for integration in to a Navy electric drive combatant.

Two Level System Loss in Superconducting Microwave Resonators

Abstract: High quality factor, i.e. low loss, microwave resonators are important for quantum information storage and addressing. In this work we study the resonance frequency and loss in superconducting coplanar waveguide resonators as a function of power and temperature. We find that there is increased loss at low power and low temperature. The increased loss is attributed to the existence of two-level systems (TLS) at the surfaces, interfaces, and in the bulk of insulators deposited on the structures. We show that both the temperature dependence of the resonant frequency and the power dependence of the loss can be used to find the TLS contribution to the loss. The TLS intrinsic loss tangent derived from the frequency shift data at high power is shown to agree well with the direct loss measurement at low power. The former allows for a relatively fast measurement of the TLS loss. As an example, we measure the properties of amorphous AlOX deposited on the resonators and find a TLS loss tangent of 1 × 10-3.

Advances in Whole-Body MRI Magnets

Abstract: Magnetic Resonance Imaging (MRI) is the largest commercial application of superconductivity. MRI is a powerful diagnostic tool that the medical community considers as a procedure of choice for visualization of soft tissue. The recent decade has marked substantial progress in MRI magnets and systems. The 3.0 tesla horizontal field and 1.0 tesla vertical field open whole-body MRI systems have become commercially available. The superconducting magnet is the largest and most expensive component of an MRI system. The magnet configuration is determined by numerous competing requirements including optimized functional performance, patient comfort, ease of siting in a hospital environment, minimum acquisition and lifecycle cost including service. The factors that drive the magnet requirements are increased center field, maximized uniformity volume, minimized field decay and stray field, magnet compactness, long helium refill period, and more. Advances in the cryogenic technology and magnet design practice provide means for improvements in magnet performance while meeting the market requirement for continuous system cost reduction.

Flux Pump for HTS Magnets

Abstract: Magnets fabricated with HTS wire can not be operated in a true persistent mode as superconducting joints of sufficient technological quality have not been achieved to date. In order to maintain a constant magnetic field in a HTS magnet a power supply has to be permanently employed, which then leads to heat losses in the cryo-system through the employment of current leads. By using a flux pump these losses can be minimized. We present a new flux pump based on 2G HTS wire. This device energized at 77 K a 2.7 mH 2G HTS double-pancake coil to its critical current of 49 A within 112 seconds. The operating principle will be described and data of the current ramping is shown. Considering the simplicity of the device and the potential to increase the generated current to 200 A and more, this new flux pump is very promising for many superconducting devices including HTS and LTS magnets and rotating machines.

Progress With Physically and Logically Reversible Superconducting Digital Circuits

Abstract: We continue to develop a new Superconductor Flux Logic (SFL) family based on nSQUID gates with fundamentally low energy dissipation and the ability to operate in irreversible and reversible modes. Prospective computers utilizing the new gates can keep conventional logically irreversible architectures. In this case the energy dissipation is limited by fundamental thermodynamic laws and could be as low as a few kBT s per logic operation. Highly exotic and less practical logically and physically reversible circuit architectures are more attractive for us because they enable a reduction of the specific energy dissipation well below the thermodynamic threshold kBTln2. The reversible option is of interest to us because we can then experimentally demonstrate that all technical mechanisms of the energy dissipation could be cut below the fundamental thermodynamic limit. In other words, we like to set the energy dissipation record for all conventional digital technologies that (if measured in kBT ) is about one million times below the best figures achieved in commercially available semiconductor circuits. Besides, we believe that diving below the thermodynamic threshold would have impressive scientific and philosophical impacts. In the paper we introduce a new timing belt clocking scheme and present new circuits. While we still work with test circuits, some of them contain two 8-stage shift registers, one with direct and the other with inverted outputs. The energy dissipation per nSQUID gate per bit measured at 4 K temperature is already below the thermodynamic threshold. We are confident that we passed through the critical phase of the project and we simply need more time to make more sophisticated circuits. The extremely low energy dissipation converts our circuits into a natural candidate to support circuitry for any sensors operating at milli-Kelvin temperatures.

Development and Deployment of Saturated-Core Fault Current Limiters in Distribution and Transmission Substations

Abstract: Zenergy Power has been developing an inductive-type of fault current limiter (FCL) for electric power grid applications. The FCL employs a magnetically saturating reactor concept which acts as a variable inductor in an electric circuit. In March 2009 Zenergy Power, with funding from the California Energy Commission and the U.S. Department of Energy (DOE), installed an FCL in the Avanti distribution circuit of Southern California Edison's Shandin substation in San Bernardino, CA. Rated at 15 kV and 1,250 amperes steady-state, the “Avanti” device is the first superconductor FCL installed in a US utility. In January 2010, the “Avanti” device successfully limited its first series of real-world faults when the circuit experienced multiple single-phase and three-phase faults. After successfully validating the performance of a new “compact” saturated-core FCL, Zenergy Power received contracts to install a 12 kV, 1,250 amperes compact FCL in the CE Electric UK grid in early 2011 and a 138 kV, 1,300 amperes FCL at the Tidd substation of American Electric Power in late 2011.

Towards Faster FEM Simulation of Thin Film Superconductors: A Multiscale Approach

Abstract: This work presents a method to simulate the electromagnetic properties of superconductors with high aspect ratio such as the commercially available second generation superconducting YBCO tapes. The method is based on a multiscale representation for both thickness and width of the superconducting domains. A couple of test cases were successfully simulated and further investigations were made by means of structured (mapped) meshes. Here, large aspect ratio elements were used to simulate thin material layers with a reduced number of elements. Hence, more complex geometries can be studied at considerable lower computational time. Several test cases were simulated including transport current, externally applied magnetic field and a combination of both. The results are in good agreement with recently published numerical simulations. The computational time to solve the present multiscale approach in 2D is estimated as two orders of magnitude faster than other 2D methods.

Progress and Status of a 2G HTS Power Cable to Be Installed in the Long Island Power Authority (LIPA) Grid

Abstract: Underground high temperature Superconductor (HTS) power cables have attracted extensive interest in recent years due to their potential for high power density. With funding support from the United States Department of Energy (DOE), the world's first transmission voltage level HTS power cable has been designed, fabricated and permanently installed in Long Island Power Authority (LIPA) grid. The HTS cable was successfully commissioned on April 22, 2008. In 2007, a new DOE Superconductor Power Equipment (SPE) program to address the outstanding issues for integrating HTS cables into the utility grid was awarded to the current project team (LIPA II). The goal of the LIPA II is to develop and install a replacement phase conductor manufactured using AMSC's second generation wire. In addition to the replacement of the phase conductor, the team will also address the outstanding components development necessary for full scale integration into a power grid including integral management of thermal shrinkage of the cable conductor, optimization of the cryostat design to mitigate the implications of potential cable damage, and the development and demonstration of a field splice in the operating utility grid and modular higher efficiency refrigeration system. This paper will report on the progress and status of LIPA II program. In addition, in-grid operation experience of existing 1G HTS Power cable is presented.

Study of 10 MW-Class Wind Turbine Synchronous Generators With HTS Field Windings

Abstract: We study the electro-magnetic design of 10 MW-class wind turbine generator with high temperature superconducting field winding by using the FEM analysis. The design examples are presented and the generator characteristics are investigated. The 10 MW-class HTS wind turbine generator is considered to be feasible from the stand point of the electro-magnetic design. In this study, 8-pole and 12-pole generators are investigated. From the results, it is considered that the 8-pole design is preferable compared with the 12-pole design. The analysis also reveals the small synchronous reactance of the HTS wind turbine generator. Therefore, proper protection is necessary for the large short circuit current.

Feasibility Analysis of the Positioning of Superconducting Fault Current Limiters for the Smart Grid Application Using Simulink and SimPowerSystem

Abstract: One of the most important topics regarding the application of superconducting fault current limiters (SFCL) for upcoming smart grid is related to its possible effect on the reduction of abnormal fault current and the suitable location in the micro grids. Due to the grid connection of the micro grids with the current power grids, excessive fault current is a serious problem to be solved for successful implementation of micro grids. However, a shortage of research concerning the location of SFCL in micro grid is felt. In this work, a resistive type SFCL model was implemented by integrating Simulink and SimPowerSystem blocks in Matlab. The designed SFCL model could be easily utilized for determining an impedance level of SFCL according to the fault-current-limitation requirements of various kinds of the smart grid system. In addition, typical smart grid model including generation, transmission and distribution network with dispersed energy resource was modeled to determine the location and the performance of the SFCL. As for a dispersed energy resource, 10 MVA wind farm was considered for the simulation. Three phase faults have been simulated at different locations in smart grid and the effect of the SFCL and its location on the wind farm fault current was evaluated. Consequently, the optimum arrangement of the SFCL location in Smart Grid with renewable resources has been proposed and its remarkable performance has been suggested.

Progress in Performance Improvement and New Research Areas for Cost Reduction of 2G HTS Wires

Abstract: Second-generation (2G) HTS wires are now being produced routinely in kilometer lengths using Metal Organic Chemical Vapor Deposition (MOCVD) process with critical currents of 300 A/cm. While this achievement is enabling several prototype devices, in order to reach a substantial commercial market, the cost-performance metrics of 2G HTS wires need to be significantly improved in device operating conditions. Zr-doping has been found to be an effective approach to improve in-field critical current performance of MOCVD-based HTS wires. In this work, we have explored modifications to the Zr-doped precursor compositions to achieve three and two-fold increase in deposition rate in research and production MOCVD systems respectively. Production wires made with modified Zr-doped compositions exhibit a self-field critical current density of 50 MA/cm2 at 4.2 K and a 55 to 65% higher performance than our previous wires with Zr-doping, over magnetic field range of 0 to 30 T. We have also developed an alternate, low-cost technique, namely electrodeposition, to deposit silver overlayer on superconducting film. Wires made with electrodeposited silver are able to sustain the same level of overcurrent as sputtered silver layers. This process has been successfully scaled up to 100 m lengths.

Loss Dependence on Geometry and Applied Power in Superconducting Coplanar Resonators

Abstract: The loss in superconducting microwave resonators at low-photon numbers and low temperatures is not well understood but has implications for achievable coherence times in superconducting qubits. We have fabricated single-layer resonators with a high quality factor by patterning a superconducting aluminum film on a sapphire substrate. Four resonator geometries were studied with resonant frequencies ranging from 5 to 7 GHz: a quasi-lumped element resonator, a coplanar strip waveguide resonator, and two hybrid designs that contain both a coplanar strip and a quasi-lumped element. Transmitted power measurements were taken at 30 mK as a function of frequency and probe power. We find that the resonator loss, expressed as the inverse of the internal quality factor, decreases slowly over four decades of photon number in a manner not merely explained by loss from a conventional uniform spatial distribution of two-level systems in an oxide layer on the superconducting surfaces of the resonator.

New Concept for Flywheel Energy Storage System Using SMB and PMB

Abstract: Since a few years ago, electrical energy storage has been attractive as an effective use of electricity and coping with the momentary voltage drop. Above all, flywheel energy storage systems using superconductor have advantages of long life, high energy density, and high efficiency. Our experimental machine uses a superconducting magnetic bearing (SMB) together with a permanent magnet bearing (PMB) and plans to reduce the overall cost and cooling cost. Flywheel energy storage systems operate by storing energy mechanically in a rotating flywheel. The generating motor is used to rotate the flywheel and to generate electricity from flywheel rotation. The generating motor consists of a 2-phase 4-pole brushless DC motor and a Hall sensor. A purpose of this study is the development of a compact flywheel energy storage system using SMB and PMB with new concept. This paper shows the new model of flywheel by using the concept of yajirobei (balancing toy) that the center of gravity of mass is lower than supporting point. By using this concept, the flywheel has higher storage energy compared with conventional ones. Furthermore, we also purpose to improve and evaluate motor drive (DC motor) to increase the rotational speed, and estimate the system at momentary voltage drop.

Cabling Method for High Current Conductors Made of HTS Tapes

Abstract: A small-scale test of a twisted stacked-tape conductor made of coated YBCO tapes was performed using four-tape cable. The critical current degradation and current distribution of this four-tape conductor was evaluated by taking account the twist-strain, the self-field and the termination resistance. The critical current degradation for the tested YBCO tape may be explained by the perpendicular self-field effect solo. The critical currents of the twisted stacked-tape conductor with four-tape cable have been confirmed not to degrade up to 120 mm twist pitch length. This type of conductor design is proposed to make it possible to fabricate highly compact, high current cables from multiple flat HTS tapes.

Status of Superconducting Cable Demonstration Project in Japan

Abstract: The HTS cable demonstration project, called the Yokohama Project, supported by Ministry of Economy, Trade and Industry and the New Energy and Industrial Technology Development Organization, was initiated in Japan in 2007. The aim of this project is to operate a 66 kV, 200 MVA high-temperature superconducting (HTS) cable in a network of the Tokyo Electric Power Company to demonstrate cable reliability and stable operation. Total project period was changed from 5 years to 6 years. Chosen as the demonstration site was the Asahi substation in Yokohama. Based on the analysis of the network conditions of the demonstration site, specifications of the HTS cable system were determined. Element technologies were developed and various preliminary tests using short core samples were conducted to confirm the HTS cable design. A 30-meter HTS cable system was manufactured and tested prior to initial demonstration tests. Long-term demonstration tests of the HTS cable system in an actual grid at the Asahi substation are scheduled to be started in 2011.

Assessment of the Impact of SFCL on Voltage Sags in Power Distribution System

Abstract: This paper assesses and analyses the effects of superconducting fault current limiter (SFCL) installed in power distribution system on voltage sags. First of all, resistor-type SFCL is modeled using PSCAD/EMTDC to represent the quench and recovery characteristics based on the experimental results. Next, typical power distribution system of Korea is modeled. When the SFCL is installed in various locations from the starting point to end point of feeders, improvement of voltage sag is evaluated using the Information of Technology Industry Council (ITIC) curve of customer's loads when a fault occur. Finally, future studies needing to apply SFCL to power distribution system are presented.

Lap Joint Resistance of YBCO Coated Conductors

Abstract: The National High Magnetic Field Laboratory is constructing a 32 T all superconducting magnet. The high field insert coil, which produces about 17 T field, will be made of YBCO coated conductor. Due to the limited available coated conductor piece length, solder splice joints are necessary in the insert coil. In order for the magnet to achieve stable operation with reasonable liquid helium consumption, it is important to minimize the resistance of the joints. In this paper, we prepared 40 mm long lap joints made by 4 mm wide SuperPower coated conductors. Joints made from different conductor batches are soldered with Sn63Pb37 solder at different temperatures using different soldering method. The joint resistivity measurements were performed at both 77 K and 4.2 K in high magnetic fields with different field orientations. We found that the joint resistivity is strongly correlated with conductor batch number. The joint resistivity temperature, magnetic field and field angle dependence is not strong. Therefore the joint resistivity measured at 77 K self field can be used to approximate that at 4.2 K in magnetic field.

Magnitude of the Screening Field for YBCO Coils

Abstract: Screening current induced in a YBCO-coated conductor coil causes two major problems; (i) reduction in the central magnetic field and (ii) temporal magnetic field drift due to flux creep. They constitute disadvantages for YBCO coil applications such as NMR, MRI, accelerator and high field magnets. The second problem is effectively suppressed by current sweep reversal, while the first remains unsolved. The present paper demonstrates that the screening current-induced magnetic field (screening field) is dominated by (a) the YBCO coil shape, (b) the YBCO-coated conductor width, (c) the coil inner diameter and (d) the ratio of operating current to the coil critical current. The dependence on these quantities is systematically investigated by numerical simulations. We conclude that coils with a smaller width of YBCO-coated conductor, a larger inner diameter and a higher ratio of operating current to the coil critical current generate a smaller central screening field ratio.

SMES Based Excitation System for Doubly-Fed Induction Generator in Wind Power Application

Abstract: This paper proposes a Superconducting Magnetic Energy Storage (SMES) based excitation system for doubly-fed induction generator (DFIG) used in wind power generation. The excitation system is composed of the rotor-side converter, the grid-side converter, the dc chopper and the superconducting magnet. The superconducting magnet is connected with the dc side of the two converters, which can handle the active power transfer with the rotor of DFIG and the power grid independently. Utilizing the characteristic of high efficient energy storage and quick response of superconducting magnet, the system can be utilized to level the wind power fluctuation, alleviate the influence on power quality, and improve fault ride-through capability for the grid-connected wind farms. According to the system control objective, the system can contribute to the stability and reliability of the wind power grid-connected system. Using MATLAB SIMULINK, the model of the SMES based excitation system for DFIG is established, and the simulation tests are performed to evaluate the system performance.

Tests on a Superconductor Linear Magnetic Bearing of a Full-Scale MagLev Vehicle

Abstract: A full-scale MagLev vehicle prototype has been developed by the team of the Laboratory for Applied Superconductivity from the Federal University of Rio de Janeiro. This vehicle is named MagLev-Cobra (cobra means snake in Portuguese), because it is composed by several modules and its motion in curves resembles the movement of a snake. The suspension technology proposed for this vehicle is the levitation of bulk superconductors above a rail made with Nd-Fe-B magnets and steel. The main advantages of the MagLev-Cobra vehicle are low energy consumption, negligible noise emission, curvature radius of 45 meters and capability to ascend ramps of 15%. These properties allow the vehicle to be perfectly adjusted to big cities layout and to be constructed along roads and rivers. One of the most important parts of this project is the superconductor linear magnetic bearing (SLMB) development for the MagLev. In this work, some new results of the SLMB are presented. Measurements of the vertical levitation force of the SLMB and the effect of the flux creep on this force are presented. Also, some tests were made to investigate the influence of the load variation on the levitation force and the SLMB levitation gap. Finally, some tests were made to measure the levitation force and torque in the cryostat for an angular displacement between it and the magnetic guideway. These tests simulate the vehicle operation in real conditions.

High Temperature Superconducting Degaussing From Feasibility Study to Fleet Adoption

Abstract: The need for increased magnetic signature control on Navy ships has lead to the development and adoption of a three axis advanced degaussing system. While this system is effective in reducing the ship magnetic signature, it requires significantly more copper cable than the legacy two axis systems. Degaussing only requires DC currents for field manipulation. Since DC applications is where HTS use excels, a feasibility study was conducted in FY04 to determine the benefits of HTS when used in an advanced degaussing system. Results showed reduced system size and weight, while remaining cost neutral. A series of lab based demonstrations were conducted proving out key aspects of an HTS DG system, most notably cooling a long length of flexible cryostat with gaseous helium. This led to an at sea demonstration of a single HTS DG loop aboard the USS Higgins. This was the first HTS system installed on an active combatant, and it made a successful magnetic range run in April 2009 demonstrating its capability to perform in a naval environment. This paper details the development of the HTS DG system from the initial feasibility study through the successful demonstration onboard the USS HIGGINS.

SQUIDs vs. Induction Coils for Ultra-Low Field Nuclear Magnetic Resonance: Experimental and Simulation Comparison

Abstract: Nuclear magnetic resonance (NMR) is widely used in medicine, chemistry and industry. One application area is magnetic resonance imaging (MRI). Recently it has become possible to perform NMR and MRI in the ultra-low field (ULF) regime requiring measurement field strengths of the order of only 1 Gauss. This technique exploits the advantages offered by superconducting quantum interference devices or SQUIDs. Our group has built SQUID based MRI systems for brain imaging and for liquid explosives detection at airport security checkpoints. The requirement for liquid helium cooling limits potential applications of ULF MRI for liquid identification and security purposes. Our experimental comparative investigation shows that room temperature inductive magnetometers may provide enough sensitivity in the 3-10 kHz range and can be used for fast liquid explosives detection based on ULF NMR technique. We describe experimental and computer-simulation results comparing multichannel SQUID based and induction coils based instruments that are capable of performing ULF MRI for liquid identification.

Development and Testing of a 10-kA Hybrid Mechanical–Static DC Circuit Breaker

Abstract: This paper presents the development and testing of the prototype of a hybrid mechanical-static dc circuit breaker (CB) for quench protection of superconducting magnets based on a mechanical switch paralleled to a static CB. In normal operation, the mechanical switch is closed and it handles the continuous flow of dc current, minimizing the on-state losses. In case of intervention, the mechanical switch opens, commutating the current into the static CB that quickly interrupts and transfers the current into a discharge resistor, withstanding the reapplied voltage. This paper was carried out to face and solve some issues of this design solution being not available in the literature examples of similar applications rated for significant power levels. The operation of the hybrid CB has been successfully tested up to a current of 10 kA with a recovery voltage of about 1 kV. Special tests have been dedicated to characterize the reliability and the repeatability of the current commutation from the mechanical switch to the static CB and to characterize the arc voltage under different conditions.

8-Bit Asynchronous Wave-Pipelined RSFQ Arithmetic-Logic Unit

Abstract: We have designed and demonstrated an Arithmetic-Logic Unit (ALU) based on RSFQ technology as a required step toward building an 8-bit RSFQ processor datapath. The circuit was designed and fabricated with HYPRES' standard 4.5 kA/cm2 process. The target clock frequency of the ALU is 20 GHz. In this paper, we present the design and functionality (low-speed) test results of the 8-bit ALU.

Modular, Multi-Function Digital-RF Receiver Systems

Abstract: Superconductor digital receiver systems of increasing functionality, modularity and user-friendliness have been developed. The modular design methodology ensures that within its input-output and heat load capacity, the system can be reconfigured to perform a different function by changing the chip module and by reprogramming FPGA-based digital signal processors. One of the systems (ADR-004), originally equipped with a 10 × 10 mm2 channelizing receiver chip for signals intelligence application, was reconfigured with a 5 × 5 mm2 1.1-GHz bandpass ADC chip to perform world's first multi-net Link-16 demonstration at a U.S. Navy facility. Substantial improvements in system integration have been obtained in each successive generation of digital-RF receiver systems. The latest (third) generation system (ADR-005), hosting a 5 × 5 mm2 7.5-GHz bandpass ADC chip and an FPGA channelizer, successfully repeated the over-the-air SATCOM demonstration performed previously using a 1-cm2 single-chip bandpass digital receiver with an on-chip superconductor channelizer. This system ran error-free for over 12 hours with and without a low-noise amplifier. To our knowledge, this is the first time an X-band SATCOM receiver has been operated without analog amplification and down-conversion in a military application.

Commercial Induction Heaters With High-Temperature Superconductor Coils

Abstract: The induction heater for aluminum, copper and brass extrusion billets is an application where high-temperature superconductors (HTSs) provide clear benefits compared to conventional technology. With an energy efficiency of just some 50% for conventional technology and limitations in processing speed, the potential for improvements is evident. A novel heater design based on superconductors, and a fast product development have led to an industrial breakthrough. With one unit in operation since August 2008 and four more sold, the superconducting induction heater has become the first true commercial HTS product. Radical efficiency increases, improvements in process speed, quality and cost have been demonstrated in a rough industrial environment. In this paper we explain how to fully utilize the superconductor in this application by altering the established concepts of induction heating. The electromagnetic realization as well as cryogenic integration based on off-the-shelf cryo-coolers are described. Furthermore, operational experience from heating up 10,000 tons of aluminum (350,000 billets) in the first commercial installation is presented.