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This paper studies the current limiting behavior based on an air-core high-temperature superconducting transformer (HTST) and a group of inductor–capacitor series resonant limiters. The air-core HTST is composed of four same double-pancake type high-temperature superconducting coils made up of Bi-2333/Ag tape, and both of primary and secondary windings include two series superconducting coils. It plays the roles of inductive fault current limiting and transformation impedance; in addition, the magnetic flux saturation can also be avoided. Meanwhile, the inductor and capacitor series with the secondary winding of the air-core HTST in series resonance state are the conventional devices. The influence of them on the circuit can almost be ignored, because they are in series resonant state in normal operation. While the fault current appeared in the primary circuit, it will be limited by the impedance of the air-core HTST and the inductor without quench (the inductor and capacitor would quit the series resonant state). According to the preliminary experiment carried out in our laboratory, this superconducting current limiting module can operate as expected, and its behavior is satisfactory. [ABSTRACT FROM AUTHOR]

Currently, HVDC is in the spotlight for long-distance transmission and power connection between countries. Among them, MMC-HVDC is a new conversion technology that can solve the problems of switching loss and harmonics. MMC consists of many submodules connected in series. And the one submodule is composed of IGBTs, Diode, and Capacitor. At the transient state, the charged capacitor is discharged and added to the fault current. It will generate tens of times the surge current during the delays all IGBTs turn-off. This causes semiconductor device destruction. To solve this problem, we applied SFCL with fast response characteristics to the MMC. The response speed of the resistive SFCL is faster than that of the MMC system protection device, which can effectively limit the capacitor discharge current before the protection device operates. In this paper, AC grid, MMC-HVDC, DC cable and SFCL were modeled using PSCAD/EMTDC. After that, we confirmed the capacitor discharge current, current limiting rate, and interruption characteristics through DC line short circuit failure simulation. As a result, SFCL effectively limits the capacitor discharge current and continuously lowers the level of the fault current. [ABSTRACT FROM AUTHOR]

The medium voltage direct current (MVDC) is a promising direction of future shipboard power system (SPS). However, one of the main limitations encountered in its development is the fault isolation of DC side. This paper reveals the evolution process of short-circuit fault in typical MVDC SPS through equivalent circuit and transient simulation. Based on the analysis of protection needs, a superconducting current-limiting switch (SCLS) topology is proposed, which includes one superconducting coupled coil and two DC circuit breakers (DCCBs). The models of SCLS is built on MATLAB/Simulink and the current limiting principle and current sharing principle of SCLS are verified. The results show that the SCLS has effective current limiting performance and fault clearing effect. [ABSTRACT FROM AUTHOR]

DC fault is one of the most important and critical challenges for stable operation of DC microgrids. Resistive type superconducting fault current limiter (R-SFCL) is an ideal protective solution to limit DC fault current. However, the effect of only using SFCL may further deteriorate the DC bus voltage stability. This paper first analyzes the effect of R-SFCL on DC microgrid under different operation modes and different fault locations, and then presents a coordinated control method of SMES-battery hybrid energy storage system (HESS) and SFCL in ground fault. This method can not only reduce the fault current level but also regulate the DC bus voltage. Finally, the comparative study is conducted in PSCAD/EMTDC, the feasibility and superiority of the proposed method is verified. [ABSTRACT FROM AUTHOR]

DC fault protection is the bottleneck that restricts the development of modular multilevel converter based high voltage direct current (MMC-HVDC) system. Superconducting fault current limiters (SFCL) is an ideal protection device that can significantly limit short circuit current and enhance the fault tolerance ability of MMC-HVDC system. At present, several topologies of SFCLs have been proposed, but there is no systematical study of their current-limiting characteristics in MMC-HVDC. This paper studies the development process of DC short-circuit faults in MMC-HVDC system, and analyzes its demand for fault current limiting. Then, resistive type, saturated iron core type and hybrid type SFCL are modeled and their limiting effect of critical fault current under DC pole-to-pole fault is tested. By comparison, the current-limiting characteristics of three types of SFCL are concluded. Results show that resistive SFCL has best performance in steady state, while saturated iron core SFCL has best performance in transient state. The current-limiting characteristic of hybrid type SFCL is between the other two types. [ABSTRACT FROM AUTHOR]

DC system protection is more challenging than that for AC system due to the rapid rate of rise of the fault current and absence of natural current zero-crossing in DC systems. Superconducting fault current limiter (SFCL) in DC systems is a promising technology to reduce the fault current level and the rate of rise of the fault current, and also SFCLs have no resistance during normal operation. In this paper, the behaviors of an SFCL coil are investigated under both low impedance and high impedance fault conditions in DC systems. In the low impedance fault condition system, the SFCL coil performs effective limitation of the fault current level under different prospective fault current levels. The application of SFCLs with limited inductance in the DC system can be a potential solution to effectively suppress the fault current under low impedance short-circuit faults. The SFCL coil under the high impedance fault condition can only limit the prospective fault current when it is much higher than the critical current of the coil. [ABSTRACT FROM AUTHOR]

As the output power of wind farm is fluctuating, it is one of the important ways to improve the schedule ability of wind power generation to predict the output power of wind farm. The operation mode of tracking planned output takes the planned value issued by the grid dispatching as the control basis of wind power generation. This operation mode is easy to control, which not only meets the needs of power grid dispatching, but also improves the reliability and controllability of new energy generation. This paper introduces the traditional PI control strategy of SMES and combines the advantages of SMES and the characteristics of application scenarios, and introduces sliding mode variable structure control into SMES. Through simulation and comparison of two different control modes, it is verified that SMES adopting sliding mode variable structure control have the advantages of fast response speed and strong robustness, which can make the wind farm output stable power according to the planned value. [ABSTRACT FROM AUTHOR]

Shunt capacitors are deployed for power factor correction (PFC) to reduce the load reactive power and to provide voltage support. Nonlinear loads, such as variable speed drives, can inject harmonics into the network. If the line impedance value produces a resonance with the PFC capacitor and the injected frequency coincides with the resonant frequency, an overvoltage is produced across the capacitor, which can lead to failure or explosion. To protect the PFC capacitor, a reactor can be connected in series with the PFC capacitor and tuned at the harmonic frequency of the system resonance. This paper proposes the use of a high temperature-superconducting reactor (HTSR) as the tuned reactor. The reactor will have an extremely high-quality factor (Q) compared to the normal reactor that can never be manufactured commercially with such a high Q. The performance of the HTSR reactor in terms of its ability to protect the capacitor from overvoltage and to reduce power losses has been investigated. The results are compared with those using the conventional (low Q) reactor and show that the HTSR can significantly improve filter performance and reduce power losses in the filter. [ABSTRACT FROM AUTHOR]

For the future applications of high-temperature superconducting (HTS) cables in the smart grid with power line communication (PLC), it would be unavoidable for HTS cables to experience the PLC signals. For the normal cables experiencing PLC signals, line trap is a commonly used inserted device to block signals from radiating across other cables. With HTS cables working at low temperature, superconducting line trap (SLT) based on HTS coil and HTS electrode capacitor might play a role to achieve a desired transmission path of PLC signals across HTS cables. Since there still remains a research gap of SLT, a prototype is proposed in this paper and its characteristics are presented by principle analysis as well as experimental research. It is found that SLT can offer a higher blocking impedance to carrier signals and produce much smaller loss at power frequency than the line trap made from normal materials. [ABSTRACT FROM AUTHOR]

A capacitor made of high-temperature superconducting (HTS) electrode plates and a dielectric layer, or “HTS capacitor” for short, has the potential advantages of working with other HTS devices at 77 K and producing low conductive loss at high frequency. It may have a specific application to cryogenic systems at high frequency, such as superconducting wireless power transfer (SWPT) systems. Working with HTS resonant coil in an adiabatic container, the HTS capacitor can also reduce the heat leakage of the cooling system. Considering a lack of relevant experimental study at present, an HTS capacitor composed of YBCO (YBa2Cu3O7- $_x$) tapes and a polyimide layer is proposed in this paper and tested in an SWPT system. Its characteristics and influences on the SWPT system are presented in detail by theoretic analysis and experimental investigation. A comparative experiment is carried out between the fabricated HTS capacitor and other capacitors made from normal materials. Finally, it is confirmed experimentally that the HTS capacitor can have a high-quality factor, work with the HTS resonant coil normally at 77 K, and provide the SWPT system with a performance enhancement. [ABSTRACT FROM AUTHOR]

A highly efficient wireless power transfer (WPT) system is required in many applications to replace the conventional wired system. The high temperature superconducting (HTS) wires are examined in a WPT system to increase the power-transfer efficiency (PTE) as compared with the conventional copper/Litz conductor. The HTS conductors are naturally can produce higher amount of magnetic field with high induced voltage to the receiving coil. Moreover, the WPT systems are prone to misalignment, which can cause sudden variation in the induced voltage and lead to rapid damage of the resonant capacitors connected in the circuit. Hence, the protection or elimination of resonant capacitor is required to increase the longevity of WPT system, but both the adoptions will operate the system in nonresonance mode. The absence of resonance phenomena in the WPT system will drastically reduce the PTE and correspondingly the future commercialization. This paper proposes an open bifilar spiral coils based self-resonant WPT method without using resonant capacitors at both the sides. The mathematical modeling and circuit simulation of the proposed system is performed by designing the transmitter coil using HTS wire and the receiver with copper coil. The three-dimensional modeling and finite element simulation of the proposed system is performed to analyze the current density at different coupling distances between the coil. Furthermore, the experimental results show the PTE of 49.8% under critical coupling with the resonant frequency of 25 kHz. [ABSTRACT FROM AUTHOR]

Superconducting inductive pulsed power supplies have attracted a lot of attention due to its lower electrical loss and higher energy storage density than traditional inductors. To effectively improve charging rate and output continuous current pulses, a repetitive inductive pulsed power supply circuit topology based on high-temperature superconducting (HTS) pulsed power transformer was proposed and simulated in our previous studies. This paper aims to further study the feasibility of the repetitive inductive pulsed power supply circuit topology through experiments. A small air-core HTS pulsed power transformer and a bridge-type capacitor switching circuit were used to build the experimental platform. The experimental results show that the bridge-type capacitor switching circuit can shorten the charging time of each new cycle and the repetitive inductive pulsed power supply circuit is feasible for continuous current pulse output. [ABSTRACT FROM AUTHOR]

A quasi-continuous high magnetic field is a special kind of pulsed magnetic field with a flat-top field longer than 100 ms. This paper proposes a hybrid power supply that consists of a capacitor power supply and a generator-rectifier power supply. A dual-coil magnet is powered to generate a 65 T/100 ms quasicontinuous high magnetic field with a ripple less than 500 ppm at the Wuhan National High Magnetic Field Center, Wuhan, China. A protection circuit consists of an R-C branch and a diode array is discussed for the worst short-circuit fault, which occurs between the first turns of inner coil and outer coil. This type of faultwill produce oscillation voltage with a high peak value and high frequency on the rectifiers. A self-adaptive PI controller with the coefficients corrected by a back propagation neural network is adopted to reduce the ripple of a flat-top. [ABSTRACT FROM AUTHOR]

The objective of this paper is to evaluate the engineering feasibility of high-frequency magnet systems for the magnetic hyperthermia cancer therapy. For the effective induction heating properties of the magnetic particles with a short-time cancer therapy, the target specifications of the magnet system are 0.06 T of the peak magnetic field with 200 kHz of the operating frequency and with 300 s (5 minutes) of the continuous or intermittent operation time. From the results, the magnet designed using 200-A copper Litz wires and a magnetic core enables the reduction of one turn voltage of the coil windings to 8.47 kV. The winding loss is 3.89 kW, which suggests that the magnet can be operated without a water cooling system. Single voltage source high-frequency inverter using commercially available SiC-MOSFET (<1.2 kV) can drive the magnet with balancer circuits using variable series capacitors. [ABSTRACT FROM AUTHOR]

The superconducting dipole magnets of the Large Hadron Collider operate in a superfluid helium bath at 1.9 K. As a part of the magnet quench protection system, each dipole magnet is equipped with a bypass diode located in the helium bath. The connection between the superconducting magnet and the cold by-pass diode is made through a clamping system called "halfmoon," located at the lowest point of the cold-masses. This area is prone to receiving metallic debris residual from the assembly technological processes. The metallic debris might move and create an earth fault during helium flows that occur not only during the cool-down, warm-up, and flushing of the cryogenic installation but also during magnet quenches at high currents. In case of appearance, the earth fault is detected by the protection system of the circuit and as a consequence, the current is ramped down to zero. Subsequently, with the circuit current already at zero, the fault can be eliminated using a device denominated as the Earth Fault Burner. The fault elimination must follow a strict procedure as it is not fully risk-free. This paper describes the details of such earth fault elimination, including preliminary diagnostics and necessary hardware. Two examples from the LHC operation are described and discussed. [ABSTRACT FROM AUTHOR]

The objective of this paper is to propose a dc current interruption technology for railway dc traction systems, consisting of a dc vacuum circuit breaker with a superconducting fault-current limiter (SFCL). To this end, a 1.5-kV dc circuit breaker prototype is designed, involving a dc vacuum circuit breaker and a resistive-type SFCL serially connected. The dc vacuum circuit breaker is developed with a commutation circuit to generate a reverse injection current, and the resistive-type SFCL is composed of yttrium barium copper oxide superconducting tape. An LC current source tested the 1.5-kV prototype, showing that, when the precharged capacitor voltage is 1.5 kV, the prospective current is 47 kA increasing at a rate of 9.4 A/μs. The SFCL limits this current to ~3 kA (peak value), and then, decreases the current to 2 kA after 6 ms, followed by successful clearance via the dc vacuum circuit breaker. The proposed 1.5-kV circuit breaker will successfully clear short-circuit faults up to 47 kA by first limiting the prospective current and then interrupting it. [ABSTRACT FROM AUTHOR]

Inductive pulsed power supply (IPPS) based on multiple high-temperature superconducting pulsed power transformer (HTSPPT) modules is a novel technology for electromagnetic launching. In a compact multimodule IPPS, the mutual couplings between HTSPPT modules are unavoidable. In this paper, an IPPS with the method of improved pulse-forming process which proved to be feasible by preliminary experiment is proposed to analyze the effect of the mutual couplings. The characteristics of the mutual coupling effect on the IPPS are presented in detail by theoretical analysis and parametric simulations. The evaluation indices reflecting performances of the IPPS under the mutual coupling effect are derived from simulations, including the energy storage capacity, flux linkage, axial tensile force, output current amplitude, and so on. Parametric simulations are executed with respect to the module arrangement, the number of modules, and the arrangement radius. Finally, the analysis of mutual coupling effect is summarized, and a strategy for exploiting mutual couplings between modules is put forward to improve IPPS performance. [ABSTRACT FROM PUBLISHER]

This paper presents a single-phase ac power supply circuit that based on modified voltage-fed quasi-Z-source inverter topology; it suits to the light or the heavy load and is fit for the resistive, inductive, or capacitive load. The topology, operating principle, voltage gain, control method, and its realization by DSP are described in this paper. The feasibility and rationality of the system is verified by the simulation and experimental results. [ABSTRACT FROM PUBLISHER]

This paper proposes a new circuit topology for SMES (superconducting magnetic energy storage), which is based on a pulse link concept of two converters. A two quadrant dc chopper and a dc/ac converter connected via high frequency dc pulse link voltage. This concept has two advantages. All semi-conductor switches operate under soft-switching condition, which results in low loss generation and possibility to increase switching frequency. The other advantage is eliminating smoothing capacitor between two conversion stages. By these advantages, the proposed converter has possibility to achieve high efficiency and power density with rich controllability. This paper describes operation principles of the proposed converter. First experimental verification of this concept was conducted with small scale setup. [ABSTRACT FROM PUBLISHER]

A bidirectional repeating long pulse magnet system for room temperature magnetic refrigerator has been designed in Wuhan National High Magnetic Field Center. By using ac power capacitor bank and anti-parallel thyristors, a bidirectional magnetic field is generated and the classical crowbar is removed for maximizing the utilization of energy. For the sake of long pulse width and repeating pulse application, a special rapid cooling magnet with large inductance of 87 mH and internal cooling channels is designed. It has a 60 mm bore and 16 layers, with 7 internal cooling channels built by annular sticks between layers. Finally, the proposed bidirectional repeating long pulse magnet system with bidirectional magnetic field of + 6.2\ \T/ -\hskip-2.65pt3.8\ \T and pulse width of 193 ms has been successfully achieved. The design and implementation of the proposed repeating pulsed magnet system will be presented in detail in the paper. [ABSTRACT FROM PUBLISHER]

A repetitive pulsed high magnetic field is a useful tool for scientific research and industrial applications. In this paper, a novel repetitive pulsed power system (RPPS) adopted to generate repetitive pulsed high magnetic fields (RPHMF) at the Wuhan National High Magnetic Field Center (WHMFC) is designed. The capacitors serve as the energy storage elements in the pulsed power system, and the key issue of the RPHMF system is to decrease the loss and to charge the capacitors quickly, safely and efficiently. For this purpose, a new discharge topology is used to feed the energy stored in the magnet back to the capacitor by an additional choke coil and a resonant capacitor. The energy lost during each pulse will be replenished to the capacitor through a high frequency series-parallel resonant capacitor charging power supply (CCPS). [ABSTRACT FROM PUBLISHER]

The purpose of this paper is to propose the high-performance modulation strategy, power control and current regulation schemes for a multiple-channel current source converter (CSC) fed high temperature (HT) superconducting magnetic energy storage (SMES), which can in turn function as the frequency stabilizer and active power filter for the distributed generation system. The key is to design and implement the interleaved space vector modulation technique to suppress the switching harmonics, the dynamic capacitor voltage control to damp LC resonance as well as regulate grid currents accurately, and the DC current balancing strategy to avoid the circulating currents. The multiple-channel CSC fed HT SMES with the proposed control scheme is verified to provide good performance in power compensation and power quality improvement. [ABSTRACT FROM PUBLISHER]

This paper presents the design process and test results of a high-temperature superconducting pulsed-power transformer (HTSPPT). The primary winding of the HTSPPT is constructed out of several double-pancake-type coils connected in series. Every double-pancake-type coil is made of Bi2223/Ag tapes. The secondary winding is constructed out of several single-pancake-type coils made of normal conductors. The configuration of the HTSPPT is designed such that the primary and secondary coils are arranged in interleaving. The testing experiments show that a high-current impulse could be achieved with a small current in the primary, which proves that the designed test circuit and the configuration of HTSPPT are feasible. [ABSTRACT FROM AUTHOR]

This paper presents results of a study, experimental and computational, of a detect-and-activate-the-heater protection technique applied to a magnesium diboride (MgB2) test coil operated in semi-persistent mode. The test coil with a winding ID of 25 cm and wound with \sim500-m long reacted MgB2 wire was operated at 4.2 K immersed in a bath of liquid helium. In this active technique, upon the initiation of a “hot spot” of a length \sim10 cm, induced by a “quench heater,” a “protection heater” (PH) of \sim600-cm long planted within the test coil is activated. The normal zone created by the PH is large enough to absorb the test coil's entire initial stored energy and still keeps the peak temperature within the winding below \sim260 K. [ABSTRACT FROM AUTHOR]

Coils for pulsed magnets in the range of 50-75 T are developed with optimized combinations of conductors and reinforcement for the prototype laboratory of the Wuhan High Magnetic Field Center (WHMFC). The basic design tool is a Pulsed Magnet Design Software package (PMDS) for calculating the capacitor discharge, conductor heating, mechanical stresses and the residual stress, including plastic deformation and winding tension. A 1 MJ capacitor bank is equipped with a thyristor switch, a mechanical switch, polarity reversal switches, a current limiting inductor and a diode crowbar. The design and the test results of the magnets, of the protection inductance and of the capacitor bank are presented and discussed in this paper. [ABSTRACT FROM AUTHOR]

Three small pulsed high magnet field devices (SPHMF) which can continuously operate 20 times in rated power with different maximum magnetic field intensity from 10 T~40 T were developed in Wuhan High Magnet Field Center(WHMFC). The SPHMF systems are used to investigate the sterilization of fruit juice, magnetization of permanent magnet for wind power generator, some industrial applications and so on. The SPHMF consists of pulsed capacitor power supply, charger, control & measurement system, cryogenic system and pulsed magnet. These systems can accommodate sample room size from Φ 12 mm to Φ 18 mm and hold sample room in indoor temperature 300 K for different scientific researches and high magnetic field industrial applications. In this paper, power supply, magnet, control system and cryogenic system are presented. The total experiment results of SPHMF show that the devices are feasible, steady and reliable. [ABSTRACT FROM AUTHOR]

A new Pulsed High Magnetic Field Facility (PHMFF) is under construction at the Huazhong University of Science and Technology (HUST) in Wuhan, China. In order to provide a wide spectrum range, a modular capacitive pulsed power supply is designed to energize 12.5 MJ at 25 kV and a large variety of coils are designed for magnetic fields in the 50-80 T with pulse duration 15-200 ms, respectively. In order to energize multi-coil systems, the 12.5 MJ power supply is divided into 11 independent 1 MJ modules with a short circuit current of 44.7 kA each and 2 independent 0.75 MJ modules for 61.2 kA each. Each module is provided with its own protection inductor, thyristor switch, crowbar circuit, dump circuit, polarity-changing circuit, charging unit and switchgear. The current pulses can be modified in shape, amplitude and duration by varying the charging voltage, the number of modules and the crowbar resistors. For verifying the design scheme and gaining experience in the construction and operation of pulsed power supply, a 1 MJ prototype that is used to energize pulsed magnets for 50-72 T fields with reversible polarity has been developed. In this paper, after the introduction of the system configuration with different module types and system settings, the design of both the 1 MJ and 0.75 MJ modules is described in detail. Finally, test results of the 1 MJ prototype are presented. [ABSTRACT FROM AUTHOR]

We have proposed a superconducting thin-film fault current limiter (FCL) that uses high-resistivity Au-Ag alloy shunt layers for the protection against "hot spots". Its design enables reduction of the total length of FCL elements that can withstand high electric fields E > 40 Vpeak /cm, thus greatly reducing the cost of FCLs. In this paper, two methods to increase current capacity of the FCLs were demonstrated. The first method protects the films from hot spots by using capacitors in addition to external resistors. The capacitors decrease rapid voltage rise in the films at the moment of quenching. The second method maximizes the rated current of two parallel-connected thin films by using parallel connections via superconducting tapes, even if the critical currents of these films are largely different. We then successfully tested 'two parallel-connected YBCO films prepared by a low-cost, metal organic deposition (MOD) method. Over-current tests showed that (a) superconducting transport currents up to 380 Apeak flowed 5 cycles without quenching, which is more than 1.3 times larger than the peak value of the 200 Arms rated current and (b) after switching, E = 45.7 Vpeak/cm was achieved without film degradation. [ABSTRACT FROM AUTHOR]

Multilayer superconducting quadrature hybrids for diplexer applications are reported for the first time in this paper. The hybrids employ highly miniature lumped element components embedded within four metal layers. The thin dielectric layers between the metal layers and the small feature size of the process allow for the miniaturization of lumped element capacitors and inductors. Hybrid-coupled diplexers using lumped element hybrids and filters have been developed, fabricated, and tested. A novel filter configuration that employs inter-resonator tap connections is also demonstrated for implementation in wideband filter applications. The whole integrated high Q (quality factor) diplexer is highly miniaturized being approximately λ[sub0] /60 in size at a frequency of 1.0 GHz. The diplexer structures are amenable to superconductor microelectronics technology and can be integrated monolithically with a superconducting receiver on a single chip. [ABSTRACT FROM AUTHOR]

A pulsed high magnetic field laboratory has been funded to be established at the Huazhong University of Science and Technology (HUST), Wuhan, China by the National Development and Reform Committee. The facility is planned to be open for external users in 2011 with the implementation of various experimental techniques in pulsed magnetic fields up to 80 T. Pulse durations are in the range from 15 to 1000 ms with the magnet bore sizes from 12 to 34 mm. The pulsed power supplies are a 12 MJ, 25 kV capacitor bank and a 100 MVA/100 MJ flywheel pulse generator. The design and analysis of the power supplies and the magnets of short and long pulse durations and the multi-stage pulsed magnets with controllable waveforms are presented in this paper. [ABSTRACT FROM AUTHOR]

ARMS is the acronym for Advanced Research Magnet Systems, a project under the European Union's 5th Framework Research Infrastructures program (HPRI-CT-1999-5007). Eight partners throughout Europe cooperated in ARMS, which was coordinated by the University of Oxford, UK. The objective of the project was to build an 80 T user magnet to be installed at LNCMP, Toulouse, France. The approach chosen was the coil-ex/coil-in method, whereby a large outer coil was energized by LNCMP's unique, 14 MJ capacitor bank. The inner coil was energized by a fast, 100 kJ bank at the peak of the outer coil's field. In this paper the evolution of the coils, the conductors and other materials is outlined as is the testing and ultimate, successful use in physics experiment up to 76 T. A view of the future direction of high pulsed fields in Europe, post-ARMS, will also be given. [ABSTRACT FROM AUTHOR]

A flux-lock type superconducting fault current limiter (SFCL) can change the amplitude of the magnetic field by adjusting either the inserting resistance or the phase adjusting capacitor. However, the magnetic field coil cannot generate enough magnetic field for some time after a fault happens due to resonance between the phase adjusting capacitor and the magnetic field coil. It is also required for the magnetic field generated to be controlled for the application to High-To superconducting (HTSC) elements which have different critical characteristics. This paper proposes a flux-lock type SFCL with a control circuit for the magnetic field, which is composed of solid state switches connected with the magnetic field coil. A current limiting experiment of this model was carried out. We showed that the amplitude of the fault current as well as the magnetic field could be controlled by the sinusoidal pulse width modulation (SPWM) operation, one of the switching techniques for controlling the magnetic field. [ABSTRACT FROM AUTHOR]