Defining what a successful SUPER-conductor for a magnet is, isn’t easy. It is often underestimated to what extend the type of magnet and its application are strongly determining the conductor requirements. Whether it is a one-off magnet where cost is not an issue, a quasi-commercial small series, or a long-term commercial production of magnets, is crucially influencing the conductor choice....
We focusing on investigating the protection of meter-class REBCO no-insulation (NI) coils applied in next generation high-field magnetic resonance imaging scanners. In order to address the issue of controllable contact resistance, we proposed a method is based on an external variable resistance, which is paralleled with an NI coil to realize the controllable contact resistance. It can maintain...
Cryogenic bypass diodes have been installed in all superconducting dipole magnets (1232) and all main superconducting quadrupole magnets (392) of the Large Hadron Collider (LHC) at CERN, and operated during the physics runs since 2009. The by-pass diodes are a fundamental ingredient of the quench protection system for those main dipoles and quadrupoles magnets. Diodes are located inside the...
In general, superconducting magnets operate at high currents, and excessive joule heating due to high currents can damage the magnet when quench occurs. Therefore, a quench protection system that can reduce the magnet current quickly is required when the normal zone occurs in the magnet. For this reason, several quench protection methods are being developed to rapidly reduce the current. In...
The quenching of superconducting magnets is one of the key issues affecting the safe and stable operation of superconducting devices. The effect of Magnetic flux jump and electro-magnetic stress leads to local critical current drop, continuous accumulation of heat of joint resistance, failure of refrigeration equipment or other auxiliary equipment, etc. These effects may cause quenching of the...
Recently, a new quench protection system using capacitor and switches has been announced to rapidly extract energy from high temperature superconducting (HTS) magnets. When a quench occurs, the quench protection system activates four MOSFET switches in sequence, and the energy stored in the magnet is extracted through an external resistor through a capacitor. In previous studies, the system...
Quench protection is critical for superconducting systems, especially those containing enough energy to damage the system during quench. We propose a new quench protection approach for multi-coil low temperature superconducting (LTS) systems that minimizes the number of protection components that must be activated during quench. In this approach, the electrically (and probably also...
Previously, we verified the feasibility of using a Raman-based distributed temperature sensor (RmDTS) system to measure a no insulated (NI) high temperature superconducting (HTS) coil temperature variation during an overcurrent induced quench event. In addition, to reduce the temperature response time of the RmDTS, we further optimized the whole measurement system. However, the combination...
When a quench occurs in a high field no-insulation (NI) high temperature superconductor (HTS) magnet that consists of a stack of double-pancake (DP) coils, a large amount of current is often induced in an NI DP coil that is electromagnetically coupled with neighbor DP coils. Depending on the strength of external magnetic field, the large induced current leads to an excessive magnetic stress...
HTS coils wound with insulated wires are actually quenched, even though HTS wires have a high quench margin and can be easily damaged, if the quench protection system does not work properly, especially in the case that current density of the magnet wires is high, It should be noted that the training effects as in LTS magnets have not been observed in HTS magnets and that damaged HTS magnets...
The superconducting wires have been developed for high field magnet, transformers, motors and so on. The quench detection and protection system are essential for safety operations of the HTS facilities. The high voltage signal conditioner (HVSC) method is generally used for the quench detection and protection, however, especially for high voltage operation magnet such as international...
The Large-scale Superconductor Test Facility (LSTF) serves as an important part of superconducting magnet load testing for fusion research which concerns about the nuclear energy producing. During the testing process, quench protection (QP) is indispensable for protecting the load from being overheated damaged. In this paper, a compatible and flexible QP framework is put forward to meet the...
Electromagnetic forming (EMF) processes of sheet metal are used to manufacture several components in modern industry. The EMF process is a highly nonlinear phenomenon and its understanding is a complex task due to the coupling of the electrical, magnetic, thermal and mechanical problems. The generated electromagnetic forces in this process are directly correlated to the resulting deformed...
Rare earth barium copper oxide (REBCO) coated conductor has been promising conductor for the design of high field magnets due to its high strength, high critical current and high critical field. However, high temperature superconducting (HTS) magnets are challenging to protect due to slow normal zone propagation velocity (NZPV). No-insulation (NI) winding technology has been demonstrated to...
As part of the design justification of the ITER magnet system and in preparation of the commissioning activities, the heat deposition on the ITER cold structures has been computed in order to generate input loads for subsequent thermo-hydraulic analyses, which are essential for the assessment of the temperature margins of the superconducting cables. The Finite Element model of a 40 degree...
In order to control and reduce the vibration of magnetically controlled reactors(MCRs) with gaps core structure, accurate stress computation should be carried out. Previously, researchers proposed a finite element model for reactors core stress calculation considering Maxwell stress theory and magnetostriction effect. Giant magnetostrictive materials are used to be filed into the gaps to...
ABSTRACT: The large range of length scales presents within superconducting magnet and its heterogeneity, a straightforward numerical simulation of a magnet, considering all details of the microstructures would cost enormous time, so incorporation of the multiscale approaches into computational models can facilitate the numerical analysis. Additionally, the superconducting magnet with high...
Computational modeling of superconducting magnets allows for predicting and understanding magnet behavior. The commercial software ANSYS is a widely used finite element software for mechanical, thermal, and electromagnetic modeling of superconducting magnets. ANSYS also allows its user to create custom elements by programming the elements’ properties and its finite element matrices. These user...
FEM simulations are a standard step in the design of accelerator magnets. It is custom for accelerator applications to characterize the field quality in terms of field expansion coefficients. Expansion coefficients are usually calculated by means of a Fourier transform of the local FEM solution evaluated at points on a circle (2D) or cylinder (3D case). The accuracy of the coefficients...
Kai Zhang, Sebastian Hellmann, Marco Calvi
Paul Scherrer Institut, Villigen, CH
Lucas Brouwer
Lawrence Berkeley National Laboratory, Berkeley, CA
Abstract – In this work, we will introduce the feasibility of using A-V formula in ANSYS to simulate the magnetization process of HTS bulk materials. The iterative algorithm method (IAM) based on ANSYS APDL is firstly developed to...
Characterizing the magnetic properties of industrial magnetic materials has great significance on the development of transformers, motors and other electrical equipment. Recently, high-frequency and high-power density electrical equipment has attracted more attention. As the frequency is getting higher and higher, the losses of the magnetic core are much higher than that in the power frequency...
The High-Luminosity LHC Accelerator Upgrade Project (HL-LHC AUP) is approaching the production phase of the US-contributed Q1 and Q3 Interaction Region Quadrupoles (MQXFA). The structures for the MQXFA prototypes were design and inspected by the US-LARP (LHC Accelerator Research Program), AUP developed criteria, which will be used for the pre-series structures. As the first two full-length...
In the frame of the HL-LHC upgrade, assemblies of two 5.5 m long 11 T Nb3Sn dipoles (MBH) are expected to replace 8.3 T NbTi LHC main dipoles (MB). Double and single aperture models, each 2 m long, were built and cold tested in operational conditions. The models have design features that are verified during these tests to provide feedback for the technology development of 5.5 m full-size...
The HL-LHC Project at CERN requires the installation of 11 T Nb3Sn dipole magnets to upgrade the collimation system. Given the high operating field and current density, the quench protection of these magnets is particularly challenging. The baseline protection scheme of the 11 T dipoles is based on the quench heaters technique.
Dedicated quench tests were carried out at CERN on short samples...
In the CERN Large Magnet Facility (LMF), the series production of the Nb3Sn-based 11 T dipole magnets is currently ongoing. Results from magnet tests and observations regarding the conductor irreversible stress limitations have shown that a uniform and well-defined pre-load is crucial. The collaring force in the assembly is adjusted by the thickness of a longitudinal shim derived from the...
In the framework of the HiLumi project, the present LHC low-β superconducting quadrupoles will be substituted with more performing ones, named MQXF. MQXF will have high peak-field on the conductor (~12 T), therefore the Nb3Sn technology is needed in order to reach the target performance.
One of the main technological challenges for the Nb3Sn magnets is the coil fabrication: due to the...
The CERN Large Magnet Facility (LMF) is currently producing 5.5 m long 11 T dipole and 7.2 m long MQXFB quadrupole coils for the HL-LHC project. Both coil types are fabricated with Nb3Sn conductor and therefore produced based on the so-called wind and react process. These coils require a vacuum impregnation process to form the final electrical insulation.
The paper will present the...
The United States High Luminosity Large Hadron Collider Accelerator Upgrade Project (US-HL-LHC AUP) is designing and fabricating 11 Q1/Q3 cold masses for the interaction regions of the LHC. Each cold mass contains two 4.2 m quadrupole magnets. The Nb3Sn quadrupole magnets operate in superfluid He at 1.9 K with a nominal field gradient of 132.6 T/m. The design and fabrication of the through and...
Abstract— A future Electron Ion Collider (EIC) may require high gradient superconducting quadrupole magnets for final focusing of the hadron beam in the interaction region. Due to the closeness to the beam collision point and the narrow 25mr crossing angle these high gradient magnets will reside in close proximity to electron beam magnets, thereby requiring a very compact support structure in...
IMP is developing a Nb3Sn superconducting magnet system for a 45 GHz electron cyclotron resonance (ECR) ion source. To achieve this complicated and difficult Nb3Sn magnet, a prototype with identical cross section but half length of the magnet is proposed. Recently a single sextupole coil about 0.5 m long has been fabricated and tested. The coil has a bore size of 200 mm and was wound by using...
Circular Electron Positron Collider (CEPC) with a circumference about 100 km, a beam energy up to 120 GeV is proposed to be constructed in China. Most magnets for CEPC accelerator are conventional magnets, except some superconducting magnets are required in the interaction region of CEPC collider ring. High gradient final focus doublet quadrupoles QD0 and QF1 are required on both sides of the...
Due to the small size and low power consumption, compact superconducting cyclotron are suitable to be installed in hospital for cancer therapy, which becomes a research hotspot in recent years. China Institute of Atomic Energy has been developing a 230MeV compact superconducting cyclotron CYCIAE-230 to meet the demands of proton therapy in China. Accelerator physics design requires a strict...
A 230 MeV superconducting cyclotron CYCIAE-230 is being constructed by the China Institute of Atomic Energy. The technology of magnetic field measurement and amending processing is the primary task to realize the isochronous acceleration of cyclotron. The CYCIAE-230 has higher magnetic field, higher field gradient and dense rotation orbits. Therefore, the isochronous field and resonance...
Proton beam with an average power of 5MW-10MW have important applications in particle physics towards the intensity frontier, as well as in the advanced energy, and material science. The fixed field alternating gradient (FFAG) accelerator combines the advantages of existing accelerators, which has a higher limitation of beam energy than high power cyclotron and has a higher beam-to-grid...
This paper presents a 3D mechanical analysis study of the mechanical behaviour of the complete magnet structure of the Block-coil Dipole option for the future Circular Collider. The analysis includes three steps: (i) pre-loading with bladders and keys, (ii) cooling down from room to operating temperature, (iii) ener-gization at operating temperature. The main objective of the 3D optimization...
Superconducting accelerator dipole magnets, based on Nb3Sn technology, with a nominal operation field of 16 T in a 50 mm aperture are being considered for the Future Circular Collider (FCC) with a center-of-mass energy of 100 TeV and a circumference in the range of 100 km, or an energy upgrade of the LHC (HE-LHC) to 27 TeV. To demonstrate the feasibility of such magnets, a twin-aperture 16T...
The Italian Institute for Nuclear Physics (INFN), in collaboration with CERN, is going to build the short model in Nb3Sn of the main bending dipole for the Future Circular Collider (FCC). The magnet will be developed on the basis of the baseline design presented in the FCC Conceptual Design Report (CDR) in the end of 2018. The magnet is based on cosine-theta design, with an internal aperture...
The forecast hadronic synchrotron studied in the FCC-hh program aims to reach 100 TeV center-of-mass collision energy using 16 T bending dipole magnets along a 100 km long ring. Gaining such magnetic field occupying a reasonable volume requires new technologies to be tested and validated on demonstrators. In collaboration with CERN, CEA is developing F2D2, the FCC Flared-end Dipole...
As part of an international collaboration, CERN has recently published a Conceptual Design Review of the Future Circular Collider (FCC), a proposed particle accelerator to succeed the LHC. Under the options considered, a proto-proton accelerator with collision energies up to 100 TeV, would require approximately 4’500 Nb3Sn superconducting dipole magnets operating at 16 T fields, installed in a...
We report the design for a hybrid block-coil dipole using advanced cable-in-conduit windings. The dipole is designed for use in the arcs of an energy-doubling lattice in the LHC tunnel.
The block coil design facilitates configuration of hybrid sub-windings of Bi-2212, Nb3Sn, and NbTi, each operating to the same fraction of critical current.
The cryogenics utilizes supercritical helium,...
Aiming to develop a combined superconducting magnet for a fourth-generation ECR source operating at 45 GHz at the Institute of Modern Physics (IMP) in Lanzhou of China, a significant gain in performance can be achieved by using Nb3Sn to allow solenoids and sextupole coils to reach a high field of 12 T. In consideration of special design of the sextupole-in-solenoid shape, the supporting...
The first 100-m iron-based superconductor (IBS) tape was produced by Institute of Electrical Engineering, Chinese Academy of Sciences (IEE-CAS) using the powder-in-tube technique in 2016. Since then, the development of IBS tape provides an opportunity to propel the practical IBS application. In this study, the world first IBS racetrack coil was made using a 100-m 7-filamentary Ba1-xKxFe2As2...
The Institute of High Energy Physics (IHEP, China) has been engaged in the development of shell-based dipole magnet with common-coil configuration for the pre-study of Super proton-proton Collider (SppC) project. The first subscale magnet LPF1, with two Nb3Sn coils and four NbTi coils, reached a bore field of 10.2 T at 4.2 K. Then a higher safety margin model has been proposed as LPF2, which...
MQXF is the Nb3Sn Low-β Quadrupole magnet that the HL-LHC project is planning to install in the LHC interaction regions in 2026 to increase the LHC integrated luminosity by about a factor of ten. The magnet will be fabricated in two different lengths: 4.2 m for MQXFA, built in the US by the Accelerator Upgrade Project (AUP), and 7.15 m for MQXFB, fabricated by CERN. In order to qualify the...
Abstract: Based on the Agreement of Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) and Ministry of Science and Technology of China during the Thirteen Five-Years Plan (so called 13∙5 plan), A dedicated test complex of superconducting magnet for China Fusion Engineering Test Reactor (CFETR) will be constructed in Hefei, China. A pair of high temperature superconducting (HTS)...
Engineering design of China Fusion Engineering Test Reactor (CFETR) Central Solenoid (CS) coil had been started in Institute of Plasma Physics, Chinese Academy of Sciences. The highest field of CS coil is 17.2T when the running current is 60KA. CS magnet system mainly consists of 8 Nb3Sn coils compressed with 8 sets of preload structure. The functions of the preload structure are to apply an...
The Central Solenoid Model Coil (CSMC) project of CFETR that began in 2014 is devoted to develop and verify the manufacturing and testing technology of the large-scale superconducting magnet. The main manufacturing processes for the coil are verified by the mockup coil’s fabrication. For now, the winding for the Nb3Sn inner and outer coils are finished and preparing for its heat treatment, and...
In order to further study fusion, China National Integration Design Group designed and developed a new superconducting magnet tokamak device, China Fusion Engineering Test Reactor (CFETR). As one of the most important components of the CFETR, the CS coil will be constructed to create, form and maintain a stable operation of the plasma. The latest CFETR CS magnet system design requirements are...
Abstract:The China Fusion Engineering Test Reactor (CFETR) Central Solenoid Model Coil (CSMC) is being designed and fabricated by the Institute of Plasma Physics Chinese Academy of Sciences. In order to validate structure strength and reliability of the CS Model Coil, model analysis and seismic response analysis have been carried out. Firstly, the paper established the CFETR CSMC model by...
The design of the China Fusion Engineering Test Reactor (CFETR) has been updated since the end of 2018, the major and minor radius are enlarged to 7.2 m and 2.2 m. The CFETR magnet system consists of 16 TF coils, a eight-module CS coil, 6 PF coil and 18 CC coils. It is decided recently that a TF coil will be designed and fabricated from 2019 through 2024 by the Institute of Plasma Physics...
The CSMC are major components of CFETR to generate the magnetic field for Simulating the Central Solenoid coil manufacturing process.Several trials were performed to qualify and optimize the heat treatment procedure of the Central Solenoid coil. In the trials, gas replacement, temperature controlling, protective gas flow controlling, coil fixture, and assembling procedure were performed to...
The central solenoid (CS) of JT-60SA has four electrically independent modules, and one module is 52-layer coil combined 6 octa-pancake coils and a quad-pancake coil vertically. The CS module is supplied with current through the room temperature busbar and current feeder of the superconductor. The maximum voltage between the CS module terminals is designed to be 10 kV, the voltage between the...
The construction of a full-superconducting tokamak referred as JT-60 Super Advanced (JT-60SA) is in progress under the JA-EU broader approach projects. The magnet system of JT-60SA consists of 18 toroidal field (TF) coils, 4 modules of central solenoid (CS) and 6 equilibrium field (EF) coils.
CS modules are manufactured one by one, then 4 modules are stacked. Finally, the pre-compression are...
In recent years, axial flux hybrid-excited permanent magnet machines with high power density, high efficiency and compact structure have the potential application prospect in the electrical vehicles. Besides, due to the rare earth resource crisis, the less-rare-earth permanent magnet machines have been taken much attention. In this paper, an axial flux partitioned stator hybrid-excited...
In case of Surface-mounted Permanent Magnet Synchronous Motor(SPMSM), PMs are attached to the surface of laminated core. They are connected by adhesion and magnetic force. However, in order to withstand rotation of the motor, thousands of revolutions per minute, rotor-teeth between PMs are essential to hold them strongly in position.
The rotor-teeth are also ferromagnetic material, they...
Recently, much research has been conducted on non-rare-earth magnet motors due to limited reserves and high prices of rare-earth materials. Among them, a magnetic flux concentrating motor using a ferrite magnet is being commercialized in many parts. However, it is disadvantageous to high-speed operation due to the structure of the rotor. In this paper, we propose a hybrid structure of a...
As the price of rare earth permanent magnet (PM) is very high, developing of high performance electrical machines with non rare earth PM is have received extensive attention, and synchronous reluctance machine (SynRM) has show good performance when comparing with other electrical machines. The torque ability of SynRM is proportional to its saliency ration which is determined by the rotor...
Post-assembly magnetization is usually used in manufacturing process of high-speed permanent magnet(PM) rotors. This paper reports the optimization and test of a saddle-shaped post-assembly magnetizing coil for a 300kW 2-pole high-speed permanent magnet (PM) rotor. The required magnetizing space is 85 mm in diameter and 200 mm in length. A saddle-shaped coil structure is proposed, which...
Weihua Huang, Junchen Zhao, Jin Wang*, Libing Zhou
State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Schoole of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
Abstract
With the increasing demand for electric vehicles, electric power steering (EPS) system is in the spotlight. The EPS system has high...
The vibration occurring in an electric motor can be largely divided into mechanical vibration due to nonaligned bearings and shafts, and electromagnetic vibration by the electromagnetic force. For existing industrial electric motors, the mechanical vibration associated with the life of the motor was the most important concern. However, in recent years, electric motors—such as the ones used for...
In order to cope with environmental pollution caused by the recent increase in electric power consumption, 'Minimum Energy Performance Standards(MEPS)' is being implemented in developed countries. MEPS is a policy to regulate the efficiency of the motor, which is a large part of the industrial power consumption, and it is a policy to prohibit the use of low efficiency induction motors....
[Introduction]
Permanent magnet (PM) motors, which have various advantages such as the wide operation range and high power density, are widely developed in various industrial fields such as automobile, aerospace, home appliance, defense industry and so on. The study and development of the slot-less PM motor is actively underway as the servo and driving motor, because it does not have teeth...
The recent next-generation railway vehicles are aiming at energy saving and weight lightening and IPMSM(Interior Permanent Magnet Synchronous Motor) with a more improved efficiency and weight to output ratio than induction motor when rare-earth permanent magnet with high energy density is applied to synchronous motor have been developed a lot. Interior permanent magnet synchronous motor, used...
[Introduction]
It is necessary to develop a motor with high output density, high efficiency, and high control accuracy in various industries like automobiles, robots and defense industry. Among the various types of motors, Slotless permanent magnet (PM) motors having relatively structural and electromagnetic advantages over slotted motors have been continuously developed for the precise...
This paper presents a comparison of cylindrical and plane air gap magnetic couplings in which the tile permanent magnet polarizations can be either radial or tangential or axial.The expressions of the torque transmitted between the two rotors of each coupling are determined by using the finite element method . For this system, a Halbach permanent magnet (PM) array structure is applied as a...
- Introduction
Recently, a new types of high efficiency motors are increasingly receiving attention because of the minimum energy performance standards (MEPS). A permanent magnet assistant synchronous motor (PMA SynRM) has high efficiency since it does not have copper loss of rotor in comparison with induction motor. Therefore, PMA SynRM receive attention as the new type of high efficiency...
- Introduction
Compared to three-phase motors, multi-phase motors have higher torque density, smaller torque ripple, and higher reliability. In addition, multi-phase motors can be operated with other healthy phases, even if one phase fails. Therefore, with the increase in industrial applications that require fault-tolerance and continuous operation, such as EVs, military, and aerospace,...
In this paper, the influence of the change of eddy current loss of the IPMSMG (interior permanent magnet synchronous motor generator) for automotive ISG according to magnet lamination direction on the Demagnetization characteristics and vibration was studied. Reduction of the eddy current loss reduces the heat generation in the magnet and affects the demagnetization characteristics and...
This paper presents the optimal design method of cage-bars in a single-phase line-start permanent magnet synchronous motor considering the starting torque and magnetic saturation. This method consists of two procedures. First, the basic design of cage-bars is made by analytic method of a single-phase induction motor. In this case, the equivalent magnetic circuit method is used but this method...
In semiconductor photolithography equipment, high productivity and nanometer precision of the motion stages are combined to enable shrink in chip dimensions at reasonable cost. High-force density linear and planar motors drive the stages which carry the reticle mask and the wafer with acceleration levels of multiple tens to hundreds of m/s2. Superconducting actuation might be a next step to...
This paper proposes a design and optimization of ferrite assisted synchronous reluctance machine. SRM(Synchronous Reluctance Motor) could be applied in electrical vehicle traction due to its salient advantage. SRM is cheaper than traditional PMSM(Permanent Magnet Synchronous Motor) because it needs no permanent magnet or some ferrite(in Permanent Magnet Assisted Synchronous Machine), which...
Generally, when designing an electric device, the harmonic components in the electric angle of the MMF do not generate the average torque, so only the fundamental component in the electric angle is considered. Also, the back EMF and the torque ripple include only the harmonic components based on the electric angle. Therefore, the conventional MMF wave equation considers only the harmonic...
An important index in determining the performance of a permanent magnet synchronous motor (PMSM) is the maximization of using the permanent magnet (PM) inserted in its rotor. Thus, a process that verifies the demagnetization of PM is generally included in a design process of PMSM. However, the magnetization, which is also one of the important indexes in the design process, has not been much...
The Axial Flux Permanent Magnet Synchronous Motor (AFPMSM), manufacturing 3 Dimensions are limited in few ways. 3D modeling is less mass-produced with high cost of unit production because stator must roll up the amorphous electrical steel plate or be molded. The study shows AFPMSM with 3D printing technique cannot be materialized in existing motor. Under the same conditions of motor design...
In this paper, the demagnetization and vibration characteristics of a 48V 5kW BLDC ISG motor generator are analyzed according to the magnet segments. Particularly, permanent magnet is divided into 3segments and 7segments as a comparison model. According to the operation characteristics of the ISG, the driving area was divided into three areas: motoring 3000rpm, power generation area 4000rpm,...
Permanent magnet synchronous machines (PMSM) with fractional-slot concentrated winding (FSCW) configuration are featured with short end windings, low mutual coupling between phase windings, high self-inductance, high slot fill-factor, reduced losses and easy and cheap manufacturing process, which makes them best choices for many applications. Based on these merits, a novel type of FSCW...
Torque motors for servo valves were created about 50 years ago, and they are used in several military and aerospace applications. Servo valves, which are now widely used in the general industrial and simulator fields, are still the beginning of fusion devices located at the top of hydraulic devices can do. A common torque motor uses a feedback spring for the rotor's alignment. This is a...
Under the construction schedule of the next generation of Circular Electron-Positron Collider building in China, the cryogenic conception design of the detector magnet is completed, and some related preliminary research works have come out good results as well. A network of LHe tubes in the thermosiphon circulating mode, which is attached to the extemal coil wall, is used to cool the coil....
The 3rd generation synchrotron light source will use a lot of insertion device, such as SC wiggler and SC undulator, to generate synchrotron radiation photon. The cryostat of 3W1 SC wiggler magnets have been finished assembling and cryogenic testing, the test results show that in the normal operating mode (no power failures, unexpected quenches etc.) the cryostat work with close to zero liquid...
The high temperature superconducting (HTS) magnets cooled by solid nitrogen (SN2) are of great merits of lower thermal temperature gradient, better thermal uniformity and thermal stability. However, the existing cooling system cannot provide a long-term stable low-temperature circumstance for HTS magnets due to significant heat load, since they are not specially designed for the SN2. Meantime,...
The cryogenic system plays a vital role in the development of superconductivity. In a sense, superconductivity would be in more widespread use now if it were not for the problems associated with the cryocoolers needed to cool the superconducting devices or facilities. For a variety of high-Tc superconducting applications such as transformers, fault current limiters, motors, generators, power...
A conduction-cooled HTS magnet is designed and tested to produce AC magnetic field of maximum 4 T for an adiabatic demagnetization refrigerator (ADR). The magnet equipped with extensive copper thermal drains is conductively cooled by a GM cryocooler to approximately 5 K and stably generates alternating magnetic field between 0 and 4 T at 0.2 T/s. The fastest ramping rate that dictates the...
The design of a large purpose built cryogen-free magnet is reviewed. The system has been manufactured for the Fundamental Neutron Physics Beamline (FNPBL) at the Spallation Neutron Source (SNS), Oak Ridge, Tennessee.
The magnet system will house a custom spectrometer and be used to measure a, the electron-neutrino correlation parameter, and b, the Fierz interference term in neutron beta...
Abstract
High temperature superconducting (HTS) taped stacks have broad application in magnetic levitation because of uniform induced current distribution, good heat dissipation and preferable mechanical properties. Configuration of the stack has a great influence on the uniformity and strength of the trapped magnetic field. In this paper, 3D modeling and experiments of HTS taped stacks with...
Abstract-Stacks of commercial high temperature superconducting (HTS) tape can be magnetized to act as strong magnets for magnetic levitation. Based on our laboratory's high temperature superconducting magnetic levitation platform, in this paper, commercial superconducting tapes are used for stacking to replace the superconducting bulks. We stacked new model round bulk with a diameter of...
The top seed method and the interior seed method are com-bined for the purpose of improving the electromagnetism of the superconductor by removing defects such as processing and cracks in the YBaCuO crystal. The top seed melt growth process is widely used as a process for growing superconducting bulk.When measuring the magnetic levitation force on the upper surface of YBCO superconductor, the...
Dynamic behavior with the hysteresis of the levitation force of a magnet-superconductor system is investigated with application of an alternating magnet field. The effect of a resonance swinging and break-off of the samples from the levitation level is found. Subharmonic resonance associated with the nonlinear of levitation dynamics is shown to the system. The critical amplitude vs. the field...
The levitation properties of permanent magnet-superconductor systems have been studied for a long time. Recently it has been demonstrated extensive possibilities of application of stacks, slabs and windings from HTSC tapes for levitation systems.
In this work a design of a superconducting passive magnetic levitation bearing on the base of HTSC flexible tapes is proposed and implemented. The...
The magnetic gear can prevent the noise, vibration, and damage due to the noncontact drive.
Many papers have been published with regard to the design of magnetic gears. However, most design methods in the study only considered magnetic properties. The structure of the magnetic gear has two voids, and permanent magnets are located on the inner and outer rotor. And, a fixed-pole is located...
At temperatures near absolute zero, the materials used in the superconducting magnetic suspension device are chemically inactive and the electrical losses are very low, which makes the device have a high accuracy in measuring angular velocity and angular displacement. In order to determine the accuracy of the device, it is necessary to carry out the drift test for the device. One of the...
Magnetic gear which is capable of non-contact transfer torque has replaced mechanical gear and has advantages of high-efficiency and improved reliability. Common electrical devices, such as motors and generators, have a single air gap. However, there are two air gaps in the magnetic gear, and a laminated structure called a pole piece is arranged between the two gaps at regular intervals in the...
Because typical electrical devices cannot be driven without a power converter, the use of gears is essential. Various studies have focused on magnetic gears without mechanical losses. In certain linear motion systems, such as wave energy power generators, using linear gears is inevitable. The most important aspect of gears in linear systems is manufacturing feasibility. Recently, research on...
A magnetic bearing uses eddy current sensors or Hall sensors to detect rotor displacement, which results in the problems such as large volume, increased cost and reduced reliability. Therefore, the research on self-sensing methods of rotor displacement for magnetic bearings has theoretical and application value. State estimation method and parameter estimation method have problems such as...
Besides the advantages of the conventional magnetic bearings such as high speed and high precision, AC magnetic bearings also have strengths such as small size and low cost because of the use of mature technology of inverter driving. Therefore, AC magnetic bearing has potential application prospects in industrial manufacturing, aeronautics and astronautics, wind power generation and other...
With the development of energy saving and advanced equipment in the modern industry, the requirement of high-speed and high-power density motor are developing. Compared with the conventional bearings, magnetic bearings have the advantages of no friction, no lubrication and sealing, high speed, high precision, long service life. Thus, Magnetic bearings have been widely used in high-speed...
Comparing with traditional bearings, magnetic bearings have the advantages of no friction, no lubrication, high speed, high precision, long life, etc.. Therefore, magnetic bearings have broad application prospects in the fields of flywheel energy storage, wind-generated electricity, high-speed machine tool and so on. The six-pole hybrid magnetic bearing is driven by a three-phase inverter,...
It is crucial to calculate the levitation force in the designation of superconducting magnetic bearing (SMB). Due to the external disturbances or the time-variable load, it is necessary to study the dynamic levitation behavior in order to ensure the stable levitation of SMB. In this paper, we investigate the dynamic behaviors of the axial levitation force for the radial-type SMB. By adopting...
We are studying magnetic bearings combining multiple cubic superconducting bulks. Calculate the placement by optimum calculation so that the fluctuation of the trapped magnetic flux distribution is minimized according to the cubic bulk arrangement and decide the optimum arrangement for the magnetic bearing.
In this experiment, eight magnetic cubic blocks were arranged in a square to...
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INTRODUCTION
Recently, magnetic levitation techniques have been developed for various fields such as energy storage flywheels and magnetically levitated vehicles. Thus, there are many reports about levitation techniques using high critical temperature (Tc) superconducting magnetic bearings (SMBs) composed of superconducting (SC) bulk and permanent magnet (PM). In this paper, new SMBs...
Studies on coaxial magnetic gears (CMG) have been actively conducted. CMGs can replace mechanical gears as they can perform noncontact power transfer, thereby minimizing loss and damage from friction.
However, the permanent magnet eddy current loss among the electromagnetic field loss of the magnetic gear is pointed out as the biggest problem in the high speed drive. Among other losses, iron...
A HTS linear synchronous motor (LSM) that uses YBCO-coated conductor as the secondary excitation system and double layer concentrated windings as the primary was recently demonstrated in our laboratory. Two YBCO-coated conductor racetrack coils were wound on a fiberglass frame via the epoxy impregnation technique and injected dc currents to provide a high stationary magnetic field for LSM....
Recently non-insulation (NI) HTS coils using coated conductors (CCs) draw extensive attention because of their self-protecting capability. Closed-loop coils are also promising in the application of electrodynamic-suspension (EDS) Maglev train with superconducting magnets since the heat load of the on-board magnet can be significantly reduced, typically >50%. Therefore, closed-loop NI-HTS coils...
Recently, we investigated High Temperature Superconductor (HTS)-ElectroMagnet (EM) interaction characteristics with experiments and computer simulations. In this investigation, new type of EMs with different geometries were designed and built for comparative analysis. We also set up a three dimensional force measurement system to evaluate the levitation and guidance forces with different EM...
In this paper we present a quadratic approximation method for the limit value of magnetic stiffness in a high temperature superconducting levitation system. The levitation configuration discussed is that of a cylindrical permanent magnet (PM) placed above a coaxial high temperature superconductor (HTS). The magnetic levitation force between the PM and the HTS is obtained on the basis of Kim’s...
A new type of electromagnetic guideway for high temperature superconducting maglev was proposed in this paper. The guideway unit is a fan shaped electromagnet that can generate magnetic field for providing enough levitation and guidance forces. A simple multi-object optimization method was used in order to determine the relative optimal geometrical parameters, so that the electromagnet can...
Superconducting permanent magnet such as bulk, stack tapes and ring-shape magnet has been proved to be a potential candidate for superconducting motors. In real applications, especially the superconducting electrodynamic-suspension(EDS) levitation system, vibrations in all directions during high speed operation are unavoidable. This paper focuses on the demagnetization process of...
The “Divertor Tokamak Test” is an experimental machine currently under construction in Italy, at the Frascati research center of ENEA. The main goal of this project is to explore various divertor solutions for defining the best way to manage power and particles exhaust, in view of the realization of the EU-DEMO machine. The DTT magnet system is fully superconducting and it is based on NbTi and...
ReBCO-CORC wires, long dreamed about practical high current density thin conductors, are now reality and feature diameters in the 2 to 4 mm range. They are multi-purpose, but at CERN specifically developed for application in high-field magnets. CERN is interested to further aid the development of such conductors for possible implementation in the next generation of accelerator magnets and...
Superconducting Nb3Sn accelerator magnet technology start to reach maturity and the 11 T dipole magnets based on that technology are prepared to be installed in the LHC. Performing detailed diagnostics on Nb3Sn model magnets has been vital for giving feedback on the design and fabrication of the magnets and for the conductor performance in that particular configuration. In the last few years,...
Advanced Conductor Technologies has been developing high-temperature superconducting Conductor on Round Core (CORC®) cables and wires wound from ReBa2Cu3O7-x coated conductors for use in high-field magnets. Initial development is aimed at CORC® cable performance goals of operating currents exceeding 5-10 kA and engineering current...
Fluctuation of critical current along the length of conductor is commonly observed in the 2nd generation of high-temperature superconductor tapes. In difference to low-temperature wires it seems that an elimination of this adverse feature is not a simple task. Then it would be sensible to incorporate its description in the standard tape characterization. We report on our effort to develop the...
The “Divertor Tokamak Test” is an experimental machine currently under construction in Italy, at the Frascati research center of ENEA. The main goal of this project is to explore various divertor solutions for defining the best way to manage power and particles exhaust, in view of the realization of the EU-DEMO machine. The DTT machine is relatively compact, and the magnet system works at high...
A pancake coil was prepared with a length of 15-strand ReBCO 2G Roebel cable and studied in detail at different operating temperatures between 4.2K and 77K, cooled with either liquid cryogens or flowing liquid helium gas. The coil was impregnated with epoxy and the transient cooling was predominantly by conduction from current contacts. Critical current measurements were carried out with a...
The use of silicon carbide varistors for quench protection of superconducting magnets has previously been reported [1], where the varistor unit is external to the magnet in a room temperature environment. Here it has been demonstrated that, in comparison to similar linear resistors, the varistor has beneficial effects in both limiting the magnitude of clamping voltages as well as limiting the...
Research and engineering design work of superconducting magnet system of CFETR (China Fusion Engineering Test Reactor) is in progress and supported by China government. The major radius and minor radius of CFETR is designed as 7.2 m and 2.2 m, respectively.
For one hands, such big size will bring big challenges to the magnet system because it will be difficult to get high enough volt...
The National High Magnetic Field Laboratory (NHMFL) is in the fortunate situation to put substantial effort into advancing all three high field magnet relevant types of high temperature superconductor (HTS) technologies, REBCO, Bi-2223, and Bi-2212, as a part of its commitment to develop all-superconducting high field magnets. Here we are presenting our work on Bi-2212 coil technology, which...
Winding REBCO conductors on round cores (CORC) has innovatively transformed REBCO thin tapes to round cables which allow high temperature superconductor to meet low-inductance requirement and offer symmetrical electromagnetic and mechanical properties for large-scale high field accelerator magnets. HTS conductors, however, are known for slow quench propagation and large minimum quench energy,...
Design of CFETR TF Prototype Coil
Wu Yu, Shi Yi, Lu kun, Liu Xiaogang, Qin jinggang, Liu Xufeng, Hao Qiangwang, Li Junjun, Hu Yanlan, Xiao Yezhen, Shen Guang, Han Houxiang, Wei Jin, Fang Chao, Yin Dapeng, Li Jiangang.
Abstract
China Fusion Engineering Test Reactor (hereinafter referred to as “CFETR”), based on ITER technology and bridged between ITER and DEMO, has been supported by China...
Two subscale coils of Bi-2212 wire have been made and tested in a DOE STTR collaboration between Cryomagnetics and the Applied Superconductivity Center at Florida State University. The coils are used to test the feasibility of using small-diameter wire in a solenoid configuration where single strand wire performance is crucial. If successful, the implementation of small-diameter wire into high...
Hybrid electric aircraft requires high power density for power transmission, which makes the ReBCO conductor-on-round-core (CORC) cable a powerful candidate for the transmission line used in the hybrid-electric aircraft. However, quenching remains one of the biggest challenges in the development of CORC cable, for it can significantly influence the thermal stability and safety of the CORC...
In DEMO fusion reactor the confinement of the plasma is achieved through the magnetic field generated by superconducting coils. The DEMO magnet system includes 16 Toroidal Field (TF) coils, 6 Poloidal Field (PF) coils and 5 modules for the Central Solenoid (CS) magnet. For the TF coils, four winding pack options are presented: one solution reproduces the ITER concept with radial plates,...
Numerous high current conductor designs based on High Temperature Superconducting (HTS) materials for fusion magnets have been recently proposed worldwide.
One of the most promising is the Twisted-Slotted-Core Cable-in-Conduit-Conductor comprised of an aluminum core with twisted slots in which REBCO tapes are stacked and with an external metal jacket. The coolant flows in a central hole and...
Stacks of high temperature superconducting (HTS) tapes magnetized by pulsed fields have been demonstrated a way for the development of the HTS magnet capable of trapping high field. A novel structure of the flux pump was proposed to magnetize the HTS magnet stacks of RE (RE= rare earth) Ba-Cu-O annular plates in this paper. Prototypes of the flux pump constructed of two types of the solenoidal...
We have shown that a persistent current can be induced in HTS coils with the form of double pancakes or single solenoids by the technique of joint-less winding with 2G REBCO tapes. However, the inevitable gap located at the center of the joint-less coil caused very poor magnetic field homogeneity, which was shown by the magnetic field mapping from the previous experimental work. In this paper,...
The critical current degradation of YBCO coils have been observed in a large number of experiments, which have been explained that the thermal expansion mismatch between the YBCO tapes and resins lead to damage of the conductor. The no-insulation coil can avoid the performance degradation, but it has a poorer mechanical strength without any reinforcement. A new impregnation method by ice was...
The 25 T all superconducting magnet designed as a combination of 14 T low temperature superconductor (LTS) background field magnet and 11 T YBCO insert coil has been developed at Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). The electromechanical properties of YBCO coated conductors and magnetic field intensity and orientation dependence of the critical current were...
The advent of REBCO tape has led to the development of tape-wound coils by a number of organizations. The 32 T magnet at the NHMFL uses two coils made of double-pancakes of REBCO installed within five LTS coils. It reached full field in December 2017. This is the highest field produced by an all-superconducting magnet to date. Since the 1970s it has been known that screening currents exist in...
In this article, we presented a design and experimental results of a Bi2223 superconducting magnet cooling by a free-piston stirling cryocooler. Depending on mechanics, thermal and electromagnetic multi-field couple analyzes results, we winding the coils with the type pancake type. We optimized the magnetic field by iron flange at the end of coils to avoid the vertical field effect of the...
Compared to low temperature superconducting materials (LTS), Bi-2212 is more promising due to excellent current-carrying capability in ultrahigh magnetic field. In order to verify the long-line performance and small-scale superconducting magnet technology, a 2 T Wind & React Bi-2212 solenoid insert coil has been designed and fabricated at Institute of Plasma Physics, Chinese Academy of Science...
High temperature superconductor Bi2Sr2CaCu2O8+δ (Bi-2212) exhibits high irreversibility field Hc2 of nearly 100 T, and high critical current density under high field with the Jc of over 6800 Amm-2 under 4.2 K, 15 T. Therefore, it shows great potential in the fabrication of low temperature, high field magnet. In our institute, Bi-2212 multifilamentary round wires with length over 200 m have been...
Screening currents (SC) induced by varying magnetic fields may not only affect the field quality but also cause overstressing of REBCO coated conductor coils, making it a critical issue for NMR and other high-field magnets. We present in this paper results of an experimental and analytical study, performed with small REBCO pancake coils, on SC-overstressing of REBCO coil. Because SC is...
As a novel structure of second-generation high-temperature superconducting (2G HTS) tapes, narrow-stacked HTS wire with 1 mm width was proposed to reduce AC loss. Its fabricated processes are to cut the HTS tapes into 1 mm wide ones mechanically and stack them into one wire through the soldering furnace. In our previous work, compared with the traditional 5 mm wide HTS conductor, the...
The HTS windings in magnets can provide large current excitation in a limited space. However, under high level excitation condition, especially in the case of fast adjusting process, AC loss will occur and lead to reduction of thermal stability. The H-formulation method is widely used and basically meets the requirements of AC loss calculation for thousand-turns coil group. However, for...
CORC is one of the candidates for high magnetic field and large currents. We are interested in applying CORC to HTS power transformers that require not only large currents but also very low AC losses. We measured and calculated the magnetization losses of short straight CORC samples made of striated YBCO CC. The effect of the striation is certain for reducing the magnetization loss, but the...
Dynamic resistance refers to the emergence of a DC electrical resistance in a superconductor carrying a DC transport current that is exposed to an oscillating AC magnetic field1,2. This phenomenon arises due to the interaction between the transport current and moving fluxons in the superconductor. Quantitatively predicting the magnitude of this effect is important when designing and utilising...
AC loss is an unavoidable problem for a conduction-cooled HTS SMES magnet during dynamic operation, which may cause a temperature raise and affect the reliable operation of the magnet. In this paper, the 3D-model calculation method of 10MJ- annular magnet is analyzed. And then, the “Dimensionality Reduction-Inversion” method based on H-equation and homogenization modeling method is proposed,...
Our research group have proposed the introduction of transposed parallel conductors which are generally used in conventional electric power machines and devices in order to realize a large current capacity, uniform current sharing and low AC loss. In previous studies, the additional AC loss due to the formation of the parallel conductors composed of two REBa2Cu3Oy (REBCO) superconducting tapes...
AC loss is an intractable and inevitable issue on high temperature superconducting (HTS) coils and magnets. The HTS coils used in HTS applications will suffer from distorted currents when operate in malfunction. Based on this, AC loss of the double-layer racetrack coil (DRC) carrying harmonic contents in phase or out of phase has been measured with laminated silicon steel sheets (SSS) or not....
We will describe the first persistent-mode medium magnetic field (400 MHz, 9.39 T) NMR magnet which uses superconducting joints between high-temperature superconductors (HTSs). As an ultimate goal, we aim to develop a high-resolution 1.3 GHz (30.5 T) NMR magnet operated in the persistent-mode [1]. The 1.3 GHz NMR magnet requires superconducting joints between HTSs and those between an HTS and...
High magnetic field uniformity is important for various applications, including NMR, MRI and quantum computing. A novel scheme has been developed to significantly improve magnetic field uniformity in a good field region, defined by (Bmax-Bmin)/Bmin, to levels well below 1X10-6 limit achievable in modern NMR and MRI magnets with shimming. This novel scheme can achieve theoretical field...
A portable nuclear magnetic resonance (NMR) superconducting magnet with conduction-cooled cryostat system was under development with central field strength 7 T. The designed diameter of spherical volume (DSV) of the magnet is 0.05 m and the peak-peak homogeneity is 8 ppm. After shimming, the field homogeneity will be improved to 0.1 ppm over a DSV 0.01 m. The magnet is actively-shielded with a...
In this paper, we propose a new concept of “multi-bore” NMR (nuclear magnetic resonance) magnet, where multiple high temperature superconductor (HTS) NNR magnets are closely positioned to form a magnet array. A key benefit of the multi-bore NMR system over its single-bore counterpart may be that it shares some common parts, especially cryogenic system and current lead, thus the overall...
In this paper, a new design method using a stacked multilayer ferromagnetic shim is proposed and experimentally verified. Because of large harmonic errors caused by the screening-current induced magnetic field (SCF) and absence of superconducting active shim coils, ferromagnetic shimming is one of the most important technologies to develop the homogeneous high temperature superconducting (HTS)...
In the ultra-high field NMR (nuclear magnetic resonance) and MRI (magnetic resonance imaging) application with using high-temperature superconducting (HTS) materials, the elaborate analysis of multiple coaxial solenoid coils is essential for the magnet design. The inductance and force were calculated by some authors using analytical and semi-analytical expressions based on double integrations...
A joint method for enlarging the length of a superconducting coil should be developed in order to cope with the power demand of industrial society. There are many kinds of joint methods are proposed to enlarge the length of a superconducting coil with high electrical reliability. Among them, a stop joint box method is known as the most promising method to enlarge the length of a...
With the rise of power level of high power device like magnetic power supply systems of fusion device, the section size of smoothing and current-limiting reactor becomes larger and larger. To keep the linearity of inductance, the structure of air-core with vacuum pressure impregnation (VPI) casting is widely used. In this paper, a numerical method based on equivalent model is adopted to study...
Two types of new organic resins are under development at KEK for the magnet insulation materials. One is Cynate ester resins which will be used in warm magnet insulation instead of usual epoxy resins. One of its typical (possible) characteristics is its radiation hardness. We have already developed a new type of the insulation resin based on Bismaleimide-Triazine (BT) resin. BT resin was...
The insulation system is a key component of Nb3Sn superconducting accelerator magnets under construction for the LHC High Luminosity upgrade (HL-LHC). It needs to ensure the magnet operation at 1.9 K and to guarantee the functionality during the complete service life of the magnet in the accelerator under high mechanical stress and irradiation dose up to 35 MGy. A first set of experimental...
A study on the cryogenic dielectric characteristics for developing a high voltage superconducting magnet system such as a superconducting fault current limiter, a superconducting transformer, and a superconducting cable has been performed. A high voltage superconducting magnet system uses liquid nitrogen as an insulating medium as well as a cooling medium by immersing a superconducting magnet...
The construction of high-performing magnets has to take into account the mechanical properties of the employed materials, and insulation adhesion to the conductor is one of the key factors. ICAS, the Italian Consortium for Applied Superconductivity, after an R&D phase, set up a new production line to process copper conductors in order to prepare, apply and cure a cyanate ester based primer,...
Abstract-High-temperature superconductors motors driven by power electronics or its startup requires an insulation system which prevents pulse voltage in Liquid Nitrogen.Materials like polyimide(PI) or fiber reinforced plastic materials are usually used in insulation system because of its high performance.Due to driven by power electrics,repetitive square wave voltage(RSWV) will be more...
PITHIA is an advanced simulation tool, in-house developed by FEAC Engineering P.C., with currently three available modules for electromagnetic, cathodic protection and fluid-structure interaction problems (either 2D or 3D), which can effectively treat large-scale problems as well. This paper describes PITHIA’s electromagnetic module, focusing on applications such as superconducting accelerator...
Several investigations have shown that ReBCO coils wound without turn-to-turn insulation are self-quench protecting due to the current bypass through layers. However, some of the obstacles that this type of magnets face are charging and discharging delays, directly related to the generation of eddy currents increased by the low contact resistance between turns. The inter-tape contact...
Electrical equipment is tending to miniaturization and high frequency in modern industry development. High frequency transformer (HFT) has a broad application prospects whose volume obeys the law of inverse-squares of the operating frequency. Magnetic properties of its core materials under actual conditions need to be studied.
The soft magnetic ferrites, amorphous and nanocrystalline alloys...
The superconducting magnetic bearing (SMB) has great application potential in flywheel energy storage system (FESS), because of the merits of wear-free, low-drag torque, self-stable, unlubricated and vacuum-compatible operation. A fully high-Tc superconducting (HTS) FESS with a 300 kW power has been established in Japan, 2015. The next generation MW-class FESS needs a larger weight and...
Toroidal magnets are widely exploited in industry and scientific research, involving a vast spectrum of applications, such as thermonuclear fusion, particle detectors, SMES systems and medical devices. Toroidal configurations may involve different number of coils of different planar and three-dimensional geometries; to properly analyse these systems, it is crucial to determine the magnetic...
High temperature superconducting (HTS) materials are nowadays considered as possible candidates for high field magnets, e.g. for fusion and high-energy physics, and for AC or DC power applications. The development of HTS conductors requires extensive information about the impact of the main characteristics of the cable architecture on the electrical performances of the superconducting tapes or...
Recently, there have been a number of studies using empirical machine learning approaches to extract useful insights on the structure-property relationships of superconductor material. Especially, these approaches are bringing extreme benefits when superconductivity data often come from costly and arduously experimental work. However, this assessment cannot be based solely on an open “black...
Transcranial magnetic stimulation(TMS), as a new medical technology with great development prospect, has been shown to be effective in treating a variety of mental illnesses. The stimulation intensity and focality of the transcranial magnetic coil are often used to measure its biological effects. In order to improve its performance, a magnetic core can be added to the existing coil to enhance...
A 9 T NbTi superconducting magnet with large bore is designed and will be fabricated for EMPS (Electro-Magnetic Property measurement System) whose sample space is 50 mm in diameter. To satisfy the large sample space of the system, winding bore of the magnet should be larger than 100 mm in diameter. Since the winding diameter is larger than that of conventional 9 T class NbTi superconducting...
ENEA is currently working on the design of an experimental fusion reactor named DTT (Divertor Test Tokamak).
DTT magnetic system will be realized using superconductor materials thus implying the need for specific protection strategies. In particular, in case of magnet quench, detection and protection devices are needed and they represent a significant cost. The design of quench protection...
In order to protect superconducting magnets, quenches must be detected on time. Unfortunately, conventional simulation predictions are not accurate enough, because they often overestimate the quench detection thresholds. These false triggers lead to frequent and unneccessary shutdowns, which considerably reduce the availability of the entire system and become even more critical for the newly...
Quench detection of high-temperature superconducting (HTS) magnet is carried out using various signals like voltage, current and temperate from the magnet. Normally, the detection point is set to a fixed value, and when the measured value exceeded detection point, it is detected as a quench. The problem of this method is that the detection system may malfunction in a sequence that the user has...
This paper presents a summary of protection studies being performed within the scope of the High-Luminosity Large Hadron Collider (HL-LHC) upgrade with the STEAM (Simulation of Transient Effects in Accelerator Magnets) simulation framework.
The HL-LHC upgrade features new technologies that are to be introduced into the Large Hadron Collider (LHC). This includes challenging Nb3Sn-based...
Quench protection system aims to protect superconducting magnets in Large Superconducting Fusion Device (LSFD) from long time and severe conducting current. A 100kA super-high pulse current with very short pulse width produced by LC commutation circuit, flows reversely into the Vacuum Circuit Breaker (VCB) to force the magnets current cross zero, which ensures the reliable turn-off of VCB to...
The International Thermonuclear Experimental Reactor (ITER) is an international project aimed to build a fusion reactor using a magnetic confinement (Tokamak) for the high-energy plasma. This magnetic confinement it created by a set of various very large superconducting coils, mainly round poloidal field (PF) coils (upto 24 m wide) and D-shaped toroidal field (TF) coils (as high as 16m). The...
The International Tokamak Experimental Reactor relies in magnetic confinement of hot plasma. The main driver for the confinement is played by the Toroidal Field Coils (TFC). These magnets are composed by a winding pack, made of Nb3Sn superconductors, and a surrounding stainless steel structure or coil case (TFCC) which is closed by welding once the WP is inserted in the TFCC. The closure GTAW...
The ITER magnetic system includes the Toroidal Field (TF) Coils. To cope with the fatigue exercised on the TF Coils, and with the deformation resulting from the powerful magnetic fields, 3 Pre-Compression Rings (PCRs) will be placed on top of them and 3 below them. An extra set of 3 will be manufactured as spare and installed below the ITER machine in case there is a need in the future to...
The Pre Compression Ring (PCR) system is a key component of ITER magnetic system that radially constraints the Toroidal Field (TF) coils against the out of plane magnetic forces. Due to its peculiar characteristics (one of a kind component, unidirectional S2 fiberglass in epoxy matrix) an experimental campaign has been planned on both reduced and full scale specimens. The tests purpose is...
The electrical performance degradation of Nb3Sn cables in the Cable-in-Conduit Conductors design has been well documented in literature. The Nb3Sn composite strands exhibit a critical current density that strongly depends on the strain state of the superconducting filaments. During the machine operation, the conductors are submitted to several electromagnetic and thermal cycles affecting the...
Modelling by analytical approach the coupling losses of CICCs used in tokamaks remains a challenge to be reliable at all frequencies. This is usually done using either CPU consuming numerical approaches or heuristic models such as MPAS now used for ITER.
A recently developed analytical model COLISEUM (COupling Losses analytIcal Staged cablEs Unified Model) applies at various scales going...
The cryogenic circuit used to cool a large superconducting magnet such as a tokamak system must be designed while considering the cooling conductance due to the many branches.The KSTAR PF1~2 upper and low magnet have ten and eight cooling channels parallel respectively. The pressure drop of the magnets is adjusted by cryogenic valve and is maintained by a supercritical helium circulator. The...
Typical tokamak fusion device uses CS (Central Solenoid) coil to initiate plasma heating by ramping up the coil with steadily increasing current which induces the plasma inside the vacuum vessel. For the case of the KSTAR (Korea Superconducting Tokamak Advanced Research) which uses superconductor for all of its magnets, this operation brings various AC losses to the magnets including...
Conceptual design of the K-DEMO magnet system has been under way. From the up-to-date design activities, the TF magnets use two different types of cable-in-conduit conductors (CICCs) where high field region uses quite an amount of superconducting wires, but in relatively low field region, substantial amount of superconducting wires should be replaced by copper wires. The stored magnetic energy...
China Fusion Engineering Test Reactor (CFETR) is the next device in the roadmap for the realization of fusion energy in China, which aims to bridge the gaps between the fusion experimental reactor ITER and the demonstration reactor (DEMO). CFETR will be operated in two phases: Steady-state operation and self-sufficiency will be the two key issues for Phase I with a modest fusion power of up to...
The KSTAR magnet system has stably operated since the first plasma in 2008. Scientifically important results have been achieved such as long-pulse plasma operation up to approximately 80 seconds, ion temperature more than 100 million degrees, the world-longest ELM suppression, and so on. During more than 20,000 shots, the CS magnet has experienced temperature rise especially due to AC losses...
The pressure drop in Cable-in-Conduit Conductors cooled by a flow of liquid or supercritical helium is one of the key parameters for the design of the large superconducting magnet systems, which determines the heat removal capability and the thermal stability. In this paper, a new model for predicting pressure drop in Cable-in-Conduit conductors is derived based on an analogy between the...
To perform fast beam switching during spot scanning procedure, the kicker system is adopted in HUST-PTF (Huazhong University of Science and Technology Proton Therapy Facility). The rise and fall time is about 100us, and the maximum repetition rate is 250Hz. A high dynamic performance power supply is required to implement the kicker function. Utmost care should be taken to avoid...
A superconducting multi-coil magnet system has been designed, analyzed and optimized, serving as demonstrator for a high filed Magnetic Resonance Imaging (MRI). The designed superconducting magnet inductance is 3500H. The operating current is 230A. The stored energy is as high as 93MJ. The superconducting material is NiTi/Cu. The normal excitation and demagnetization are completed by the power...
The pulsed magnets power supplies systems to affect injection and extraction of the electron beam have been realized for the Taiwan Photon Source (TPS) and Taiwan Light Source (TLS). The control systems of these pulsed magnets power supplies have been achieved as the well operation interfaces. To accomplish higher reliability operation, the advanced real-time diagnostic toolkit of pulsed...
High-Tc superconducting (HTS) dynamos are simple devices that provide an effective alternative to current leads for driving DC currents in superconducting coils. The simple geometry of these devices consists of some arrangement of superconducting stators and exciter magnets. With recent advances in our ability to model such systems, we investigate the relationship between width of the...
HTS flux pump is a contactless charging method for a superconducting magnet, which can reduce the cryogenic losses associated with current leads. Rotating type flux pump is a simple and practical flux pump, which has great application in charging HTS magnets. For the rotating flux pump, the design of rotor has great impact on the performance of flux pump. In this study, we will change the...
Flux pumps are capable of injecting flux into an HTS circuit without electrical contact. They are ideal alternatives to traditional current sources and current leads to power HTS magnets. These devices make it possible for HTS magnets to be smaller, lighter, and more accessible.
In recent years, our group in Cambridge has developed a transformer-rectifier HTS flux pump switched by...
Recent progress in material science has proved that high temperature superconductors have a great potential to trap significant magnetic flux due to the characteristics of flux pinning, which makes them particularly attractive for a variety of engineering applications. However, using traditional methods to magnetise a superconductor, the applied field needs to be at least as high as the...
Recently, several high temperature superconductor (HTS) companies, such as SuperPower, SuperOx, Shanghai Superconductor Technology (SST), and THEVA, succeeded in improving current-carrying performance of their REBCO products under high magnetic field at low temperature. However, except HTS coils made of SuperPower REBCO tape, there are insufficient reports regarding thermal, electrical and...
As a novel high-temperature superconducting (HTS) conductor structure composed of the stacked 1-mm wide REBCO tapes, Narrow-Staked (NS) wire has been demonstrated to have a significant reduction effect of AC loss and screening current induced field (SCIF) in the insulated HTS coils. Thus, NS wire is a promising HTS conductor design for the practical magnet applications. Meanwhile, due to the...
Abstract:
Comparing with conventional insulated high temperature superconducting (HTS) coil, the no-insulation (NI) one has advantages of high stability, self-protection and fast quench recovery. However, the unstable and non-uniform magnetic field appear in NI coil during exciting owing to too low transverse resistivity among turns. This paper proposed a method for increasing stability and...
When high temperature superconducting (HTS) devices run in the power system, the superconducting tapes may quench due to power system fault. Therefore, quench characteristic is one of the most important characteristics of superconducting tapes. In this paper, in order to obtain the quench characteristics of YBCO coated conductor, we have established an over-current experiment system based on...
NI (no-insulation) winding method have been widely used to develop high field superconducting magnets using REBCO wires due to excellent mechanical and electromagnetic stability. When REBCO magnets are operated in a bath of cryogens such as liquid helium and liquid nitrogen, sufficient cooling is achieved by pool boiling of the cryogen. However, conduction-cooled REBCO magnets must ensure...
We have been studied the no-insulation (NI) technique and co-winding method with various metallic tapes. The improved thermal stability of NI test coils by bypassing the transport current into the transverse direction was experimentally confirmed and reported. However, there are the problems of the transient stability and the reduction of critical current of NI HTS coils due to the thermal and...
The no-insulation coil is expected as a technology that can realize both high current density and high thermal stability which are originally trade-off relationship in REBCO coil application. And this technique has been mainly studied for application to small diameter inner coil of NMR magnet exceeding 30T. In this case, the coil is cooled by 4.2 K liquid helium. On the other hand, we have...
We have tested an intermediate-size HTS stainless steel double pancake coil (132 turns per coil) and discovered dynamic effects during sudden discharge on millisecond scale. Two main approaches have been compared: soft and hard breaks. The soft break is when the power supply is turned off suddenly but the shunt resistors (168 milliohm) is still connected. The hard break uses a high voltage...
Brushless dc motor (BLDC) has high output and high efficiency characteristics. It is possible to reduce the size and weight of the device and is used throughout the society. Among them, vibration and noise reduction are becoming important issues as they are used in household appliances and automobiles adjacent to people.Vibration and noise are caused by electrical causes such as spatial...
Currently, the ISG is commercialized and under active research in the 48V hybrid system. However, in a typical vehicle using a 12V system, the starter motor and generator are operated separately. In this paper, we report the development of a general advanced integrated starter-generator(AISG) for vehicles using 12V power supplies. The specifications of the power source are lower than that of...
1) Introduction
Brushless DC motor (BLDC) have wide operating range and can high power density and high torque. Therefore, BLDC is used in various fields such as vehicle, aviation, home appliances. However, there is a problem that a torque ripple occurs in a phase commutation section in which a current flows. In order to overcome such problems, various studies have been conducted to improve...
Flux-modulated permanent magnet (FMPM) motors have attracted widespread attention in many applications due to the superiority of low-speed large-torque, such as the electric vehicles. In the type of motors, the flux modulation effect is the key to obtain the excellent torque performances, which realize the electric gear operation by forming the matching between the magnetic fields with high PM...
Flux-modulated permanent magnet (FMPM) motors have attracted considerable attention due to the predominant torque performance in low speed condition. Recently, the flux modulation principle is always to be developed in diverse PM motors. Intensive study results demonstrate that the harmonics in motor airgap are abundant, and they are essentially the deliverer during the process of the motor...
Brushless direct current (BLDC) motors have the advantage of power density and low maintenance cost compared to DC motors. DC motors are increasingly being replaced with BLDC motors due to low cost of driving devices and the development of control technology. In particular, outer rotor type BLDC motors have higher power density than inner rotor type BLDC motors since permanent magnets (PMs)...
A bearingless permanent magnet slice motor(BPMSM) has compact structure and high efficiency, which can realize the rotor magnetic suspension at five degrees of freedom. Bearingless pumps have been established in applications that demand high temperature and corrosion. The extreme environment, especially the high temperature environment, will cause the PM demagnetization fault and so on. As one...
A novel axial-radial flux permanent magnet machine (ARFPMM) is proposed to improve the performance of PM machine. The ARFPMM is capable to reach higher torque density and lower cogging torque than traditional axial and radial PM machine when designed properly. To reach higher performance, T-type SMC core, reluctance rotor, and PM rotor are applied. The T-type stator core is made of soft...
The vibration occurring in an electric motor can be largely divided into mechanical vibration due to nonaligned bearings and shafts, and electromagnetic vibration by the electromagnetic force. For existing industrial electric motors, the mechanical vibration associated with the life of the motor was the most important concern. However, in recent years, electric motors—such as the ones used for...
Spoke type Permanent magnet synchronous motors (PMSM), which are superior to other PMSM in terms of output density by maximizing the surface area of permanent magnet (PM), have recently been actively studied. However, spoke type PMSM are magnetically separated by connecting each pole of the rotor core to a magnetically saturated rib or bridge. Therefore, there is a rotor structure in which...
Nowadays, hybrid electric vehicles (HEVs) have been employed and developed extensively for promoting the rapid development of resource-conserving and environment-friendly society. Due to the multi-mode operations of the HEVs, the high integrated electric drive system with the motors which features the high torque density, high efficiency, and wide speed range are becoming the main trend in the...
This study shows the novel rotor shape of the spoke-type PMSM for a washing machine to improve power and widen operating range by changes of inductance in the rotor and air gap. Applying a new shape to the rotor results in an inductance change in some areas of the rotor in which low magnetic flux density existing, which in turn changes the magnetoresistance in the air gap. As the inductance...
Our group has been conducting various studies of high-temperature superconducting induction/synchronous motor (HTS-ISM) for next generation transportation equipment. The HTS-ISM has various advantages, such as co-existence of synchronous and slip rotation modes, high efficiency for variable speed control, high torque density. For the HTS-ISM with copper stator winding, the torque density and...
Due to the high thrust density and operational speed, superconducting linear synchronous motor is considered a favorable propulsion system for high-speed ground transportation. Korea Railroad Research Institute (KRRI) has researched on high-Tc superconducting linear synchronous motor (HTS LSM) to develop new high-speed transportation of which speed is over 500 km/h. As a feasibility study for...
Axial flux permanent magnet machines (AFPM) are being increasingly used in a great of industrial applications e.g. the electrical vehicle and wind generators, due to its very compact structure and high torque density. The single stator and single rotor configuration is the basic structure of axial flux machine. For AFPM the fractional slot concentrated winding and surface mounted PM structure...
Superconducting tape-based stacks used as trapped magnetic flux magnets in electrical machines are subject to an AC-demagnetizing field. This study provides analysis of trapped flux and demagnetization of several stacks’ architectures for electrical machines applications. This work is an application-driven enhancement of a previous study on stacks architecture in regards of trapped flux...
Flux reversal permanent magnet machine (FRPMM) is a special kind of permanent magnet machine with the permanent magnet (PM) installed on the stator side and there is no winding or PMs on the rotor side. Claw pole machine (CPM) is a special kind of transverse flux machine (TFM), with the adopted claw pole teeth, the torque ability and power factor of CPM can be even higher than those of TFM....
The objective of this paper is an analysis method for traction motor which targeting to electric bus and trailer. The type of the studied motor is IPMSM(Interior Permanent Magnet synchronous motor) which has delta type magnet topology of the rotor. It is possible to maximize reluctance torque and output characteristics by arranging the permanent magnet arrangement of the rotor in delta...
Low-speed and high-torque permanent magnet motors (LSHT-PMM) are widely used in many industrial fields. Due to the inherent characteristics, the outer diameter of the LSHT-PMM is large. Therefore, in order to make full use of the internal space of the motor, a double stator structure is proposed in this paper. In order to reduce the amount of permanent magnets (PMs) and reduce the cost, a PM...
Our group has been developing a High Temperature Superconducting Induction/Synchronous Motor (HTS-ISM) for highly efficient transportation equipment. So far, the 20 kW class prototype, which consists of BSCCO rotor and copper stator, has already been developed and shown its excellent characteristics based on experiment and analysis. Furthermore, the 50 kW class model, in which both the rotor...
Transformer is important in power system. No-load loss and apparent power of amorphous alloy transformer core change obviously with temperature. Moreover, the inner temperature varies in large scale. At present, little research has been done on no-load loss of amorphous alloy cores with temperature change. Therefore, it is very important to study the no-load loss at different...
Fully turboelectric propulsion systems with lightweight and high power density are one of the solutions to realize future electric aircrafts. Our research group started to develop 10 MW fully superconducting synchronous generators and 2 MW motors. In this system, we designed so that the generators supply electric power at the voltage of 6.9 kV, however, the motors operate at the low voltage of...
Insulation materials have different electrical characteristics according to temperature and voltage frequency. These characteristics are very significant factors for the insulation design of high voltage power apparatus. Since there are not always consistent overvoltages, it is necessary to ensure the dielectric strength against various overvoltages. In particular, high voltage power...
Residual flux of the power transformer will accelerate the magnetization saturation of transformer core and generate high transient inrush current. Generally, the peak value of inrush current generated by residual flux in the core can reach 6-8 times of the rated current, which endangers the mechanical stability and insulation strength of the power transformer windings and destroys the normal...
Conductor on Round Core (CORC®) cables with scalability, flexibility, strong mechanical strength and high current density are of large potential for different power applications. In this paper, CORC® Cables are proposed to be the secondary winding for superconducting fault current limiting transformer (SFCLT). In order to evaluate the working performance of CORC® cable in SFCLT, firstly, a...
Abstract: Based on the finite element method (FEM), a simulation model of a single-phase HTS transformer was established according to a developed HTS transformer, and the simulation results are in good agreement with the experimental data. On this basis, a 120kVA/6kV single-phase HTS transformer was designed, the primary windings were solenoid coils consisted of 8 helically wound layers, and...
Traction transformers are key components for the Chinese high speed train system, and it is hoped that a superconducting version will replace oil-based conventional transformers in this application. Since 2018 Beijing Jiaotong University has been leading a six partner project, funded by the Chinese Ministry of Science and Technology (MOST), to develop a 6.5 MVA HTS traction transformer. The...
When a large power transformer is switched on, the residual flux in the iron core may cause inrush current, which may cause the transformer to no longer be put into operation, thus affecting the continuity of power supply in the power grid. However, the traditional methods can only estimate the residual flux. It is impossible to effectively weaken the residual flux. Therefore, the study of...
This paper is a the fault current limiting characteristics of superconducting fault current limiter due to three phase ground fault in power system.
In this system, two superconducting elements are connected to a-phase and c-phase respectively, and a transformer type superconducting fault current limiter is proposed to limit the fault current in case of a ground faults.
In order to measure...
The distributed power generation has increased due to the development of the electric power industry and the active generation of renewable energy. This causes a large increase in the fault current when fault occurs, which exceeds the capacity of the existing protective device. Thus it creates a risk of shutdown failure. The superconducting fault current limiter (SFCL) has been demonstrated by...
A Wireless Power Transmission (WPT) system for a railway vehicle has been investigated to reduce the greenhouse gas emissions in a diesel vehicle. However, the WPT system is required to transmit the electric power of several hundred kW in a short time while the railway vehicle is stopping at a station. Since there are power converters and control devices under the floor of the railway vehicle,...
45 T is the highest continuous magnetic field available to the scientific user community, and this now since practically 20 years. We address the question of how to access the next level, defined as 60 T, with a hybrid magnet. The outsert, wound from low-temperature superconductors (LTS) will generate the highest field possible: 18 - 20 T in a 1 m bore. For the inner part, two approaches are...
A design study started in 2014 at CERN for a Future Circular Collider. A new 100 km ring-tunnel for the collider magnets is foreseen as well as new particle detectors to probe electron-positron (ee), electron-hadron (eh) and hadron-hadron collisions (hh). A conceptual design report is due in 2019 for all FCC collider and detector options. Baseline designs for the various Detector magnets were...
The design for a new approach to cable-in-conduit (SuperCIC) for use in the high-field windings of tokamaks. Two layers of high-field superconductor wires are cabled onto a thin-wall perforated center tube. An overwrap is applied and the cable is inserted as a loose fit into a sheath tube. The sheath tube is drawn down onto the cable to compress the wires onto the center tube and immobilize...
A 100 T pulsed magnet of triple coils was developed in WHMFC in 2018, the outer coil was powered by a 100MJ/100MW pulsed generator, and the middle and inner coils are energized by capacitor banks. The inner and middle coils are made of CuNb wire, and copper wire for the outer coil, the outline size of the magnet is 800 mm in O.D. and 1200mm high. The magnet failed at about 83 T during test,...
The magnet system of the Muon to electron (Mu2e) experiment at Fermilab consists of three solenoid magnets: the Production Solenoid (PS), the Transport Solenoid (TS), and the Detector Solenoid (DS). The S-shaped TS contains 52 coils grouped into modules, which are typically 2 coils shrink fitted into Al shells. These modules are further grouped into units made of 1-3 modules. As part of the...
The Dresden High Magnetic Field Laboratory (HLD) is a pulsed-field user facility which provides external and in-house researchers with the possibility to perform a broad range of experiments in pulsed magnetic fields [1]. Being a member of the European Magnetic Field Laboratory (EMFL), HLD receives more than 100 scientific proposals annually.
The Dresden High Magnetic Field Laboratory...
The ALPHA-g experiment at CERN aims to be the first-ever to precisely weigh antimatter under Earth’s gravity, by “dropping” antihydrogen atoms with a magnet system. The anti-atoms are initially confined inside a vertical octupole and between two end cap coils. The currents in the coils are then gradually decreased to release the anti-atoms. The up -down balance of the escapes depends on...
ReBCO-CORC Cable-In-Conduit Conductors are high-current multi-strand conductors aimed for application in large scale magnets, for example in magnets for particle detectors and fusion experiments; but also for use in bus lines feeding high currents to magnets or other devices. ReBCO based conductors open up the operating temperature range of 20 to 50 K, not accessible by any other practical...
Ultra-high field pulsed magnets must simultaneously satisfy a number of often competing electrical, electromagnetic, structural, thermal, and economic constraints. To produce the highest field possible, nondestructive pulsed magnets are designed to operate at the limits of mechanical strength and electrical capacity of conductors. In this presentation, we will introduce a coupled...
The MADMAX (MAgnetized Disc and Mirror AXion) project is a dark matter experiment that aims at finding axion particles with masses in the range of 100 µeV. In order to achieve this goal, the chosen approach is to use a detector comprised of many magnetized dielectric discs put in parallel in front of a mirror. The relevant level of magnetic induction needed to increase the probability of...
Material is a key issue for the high field magnet development. For DC resistive magnets, copper alloys with high strength and high electrical conductivity from room temperature up to 200 °C are required.
Steady high field resistive magnets developed worldwide used mainly two technologies: the Bitter and the polyhelix one. Each technology encounters material limits.
In the case of Bitter,...
Searching for axion like particles is one of the top priorities in particle physics. Using helioscopes is a promising technology to detect solar axions. The conceptual design of the state-of-the-art facility, the International Axion Observatory (IAXO), has resulted in a 22 m-long / 660 MJ stored energy, toroidal magnet system comprising 8 racetrack coils. In order to ensure readiness of the...
The EUROfusion DEMO is being designed as the fusion machine to be built after ITER. During the preconceptual phase, several design options are investigated by theoretical analyses as well as tests on newly developed conductor prototypes.
One design option for the toroidal field magnet (TF) and central solenoid (CS) is based on flat Nb3Sn forced-flow conductors made with react&wind technique....
Copper-based conductive wires with both a high strength and a high electrical conductivity could find applications in aerospace and power engineering as well as in niche scientific applications such as materials for the production of high-field pulsed magnets. Indeed, in order to produce non-destructive fields, the coils must be wound of wires with a very high mechanical strength to resist...
The Precision Experiment on Neutron Lifetime Operating with Proton Extraction (PENeLOPE) will use a large superconducting multipole magnet to trap ultracold neutrons. To achieve this, a large volume of 750$~$L needs to be enclosed within a steep magnetic-field gradient of at least 2$~$T, requiring a unique multipole arrangement with a high current density of 316$~$A/mm$^2$ and thin support...
The engineer design for CFETR, “China Fusion Engineering Test Reactor”, has start since 2017. Its magnet system includes the Toroidal Field (TF), Central Solenoid (CS) and Poloidal Field (PF) coils. The maximum field of TF will get around 14.5 T, which is much higher than that of other reactors. One full-scale TF coil will be built. Tremendous investigations need to be made in the development...
With the faraway goal of a 100 TeV new hadron-hadron collider, the ambition for very high field accelerator magnets has never been so broad. The technology choice between Low Temperature Superconductor (LTS) Nb3Sn and High Temperature Superconductors (HTS) for such a machine remains to be made and might lead to a hybrid solution. In all cases, the challenges are ahead of us: from...
The design of a large purpose built cryogen-free magnet is reviewed. The system has been manufactured for the Fundamental Neutron Physics Beamline at the Spallation Neutron Source in Oak Ridge, Tennessee.
The magnet system will house a custom spectrometer and be used to measure a, the electron-neutrino correlation parameter, and b, the Fierz interference term in neutron beta decay.
The...
Abstract—An 10T superconducting split magnet with a room-temperature bore of 40 mm was designed, manufactured and tested for X-ray diffractometer at The High Magnetic Field Laboratory in Hefei, China. The superconducting split magnet provides room-temperature splitting gap of 10 mm and scanning angle of 160 degrees for X-ray beam. As a result of magnetic field intensity considerations, the...
As a significant research method, quasi-continuous high magnetic field (QCMHF) can meet scientific experimental requirements for higher magnetic intensity, longer flat-top pulsed width and lower ripple in the field of physics, biology and other scientific fields. In this paper, a QCMHF system designed by multi-objective optimization method is present to obtain the magnetic intensity of 70T...
The repeated pulsed high magnetic field system is widely used for neutron diffraction, terahertz radiation, guiding magnetic field and so on. In these applications, more and more attentions are paid on magnetic field waveform consistency. The pulsed generator power supply, with large energy storage and controllable output voltage, is suitable for generating repeated controllable pulsed...
Repetitive pulsed high magnetic field (RPHMF) provides a novel solution for the frontier researches in the areas of condensed matter physics, materials science, biomedicine, and so on. Significant amount of attentions have been paid to the study of RPHMF by researchers. As the higher demand for magnetic field intensity and pulse frequency of RPHMF, the repeated supplement of energy storage and...
As an important extreme experimental condition, high magnetic field plays an irreplaceable role in the frontier scientific research, such as condensed matter physics, new materials processing. The main pulsed high magnetic field laboratories in the world are constantly working to generate higher pulsed magnetic field. A nondestructive magnet aimed at generating very high pulsed magnetic field...
We developed a 600kW pulsed DC power supply employing two pairs of a self-excited induction motor/generator (IMG) and a flywheel for toroidal field coils (TFCs) of Plato. Plato is a new tokamak device to measure plasma turbulence precisely, which is under construction at Kyushu University in Japan. In the presentation, we will describe the details on the structure and experimental results of...
The Deep Underground Neutrino Experiment (DUNE) has formed a near detector design group (NDDG) tasked with delivering a CDR by the end of the year. The DUNE Near Detectors will be housed in an underground hall on the Fermilab site. The two main detector systems are a liquid argon detector and a high-pressure gas time projection chamber (HPgTPC). The HPgTPC requires a magnet that generates a...
The ultimate frontier of the particle physics beyond the Standard Model is the research of axion-like particles, to explain the absence of CP violations in the strong interaction and provide dark matter candidates. In the MADMAX (MAgnetized Disc and Mirror AXion) experiment, the principle of axions detection relies on their predicted emission of an electric field proportional to the square of...
The proposed IDEA Experiment (International Detector for Electron-positron Accelerator) for probing ee+ collisions at the Future Circular Collider FCC is conceptualised around an ultra-thin, radiation transparent 150 MJ superconducting solenoid of 6 m length and 4 m free bore providing a magnetic field of 2 T for the inner tracking detector. Positioning the solenoid around the inner detector,...
The ALPHA experiment at the CERN Antiproton Decelerator facility underwent a major upgrade in 2018. Amongst other improvements, key is the rotation of the atom magnetic trap axis, which is now vertical. Bilfinger Noell designed and fabricated the 2 m long superconducting vertical solenoid, which provides the 1 T background field for the experiment. This is an active shielded, conduction...
This work was performed as part of the international Project 8 collaboration. The goal of the Project 8 experiment is to measure the absolute neutrino mass using tritium beta decays, which involves precisely measuring the energies of the beta-decay electrons in the high-energy tail of the spectrum.
The experimental installation of the Project 8 Atomic Tritium Demonstrator requires a magnet...
The Jefferson Lab 12 GeV Upgrade of Experimental End Station Hall B required a new detector system that would be more sensitive to forward going particles and handle higher luminosity. This new detector is CLAS12 and includes two superconducting iron-free magnets – a torus and a solenoid. The Torus magnet consists of 6-trapezoidal racetrack-type coils while the solenoid is an actively shielded...
Nuclotron-based Ion Collider state-of-art design involves innovative solutions in superconductive applied technology. Thanks to its consolidated experience, ASG has been directly involved into the program by providing to Joint Institute for Nuclear Research (JINR) a large 0.5 T Nb-Ti superconductive magnet (5.8m diameter, 8.1m length) equipped with active (resistive) modulation system. Typical...
The extraction line of the future synchrotron SIS100 will have a series of three normal-conducting magnetic septa which deflect the beam upwards. Underneath the third septum there will be a beam stop for emergency extraction. Therefore, the entire region will be very likely activated with anticipated doses that forbid manual installation of a heating jacket. A mechanism which would...
In high intensity circular accelerators such as Rapid Cycling Synchrotrons (RCS) and Fixed Field Alternating-gradient (FFA) synchrotron, maximum beam intensity is limited by beam loss. Suppression of beam scatterings occurred in beam extraction system, especially in septum magnets, is one of the key issues to achieve low beam loss rate. Application of massless septum may be a promising way...
An electron lens – a novel instrument in accelerator physics to manipulate hadron beams with a magnetically confined electron beam - is under development at GSI, Darmstadt. It will be used to compensate the ion beam’s space charge by an overlapping electron beam and therefore may help to increase the intensity of primary beams in the low energy booster synchrotron SIS18 for FAIR. The main...
The new accelerate facility HIAF is under constructing in IMP (Institute of Modern Physics), Chinese Academy of Sciences. It consists of a linac, a booster of BRing and a spectrometer ring of SRing and some terminals for experiments. The electron cooling technology is applied in the SRing, which is composed of solenoids and racetrack coils. In this paper, the magnetic field of the electron...
Fast kickers such as strip-lines along with lambertson magnet or thin septum magnet could support on-axis injection for Diffraction Limited Storage Ring (DLSR), in which traditional off-axis injection becomes inadequate. This paper focuses on the designing, manufacturing and process optimization of thin septum magnet. The scheme of eddy-current type thin septum magnet (the thinnest portion is...
The design of focusing solenoids used in accelerator magnets or other charged particle beam applications usually has some general design requirements such as focusing strength, stray field, and eddy current losses. In superconducting solenoids specific requirements often include mechanical stress, cryogenic performance, and quench protection. In resistive solenoids specific requirements...
The design of the compression magnet in the magnetic trap type magnetic compression device has an important influence on the compression effect. Due to the large diameter (0.3m) of the vacuum chamber, and the severe eddy current in the metal cylinder induced by the rapidly changing current (700-1100kA/100μs) of the coil, the radial distribution of the magnetic field in the magnetic mirror...
This paper develops and summarizes analytical formulations of radial and tangential stresses of superconducting, no-impregnated solenoids, based on a multilayer model. The analysis takes into account the fabrication steps (pre-winding and reinforcement), cooling-down and energization of the coil (magnetic loading). Both isotropic and orthotropic cases are considered.
Representative...
This paper deals with the mechanical characteristic and strain profile in a 5 T NbTi superconducting split magnet system, which provides a strong background field for the multi-field test facility established in Lanzhou University of China. The design of the split magnets, composed of 14 coils wound with NbTi wires, was adopted to satisfy a large test space (Φ100mm*800mm) for mounting the...
An electromagnetic force has an important effect on the performance of high temperature superconducting magnet. The superconducting magnet can be impregnated with composite resin in order to improve its mechanical stability. A three dimensional model was established by COMOSL finite element analysis software to analyze the electromagnetic stress and strain. The results show that the maximum...
Compressive magnetic radial stress is favored, over tensile one, for a high field magnet, mainly because it lowers the overall peak magnetic stress within the windings of the magnet. It is of particular importance for a no-insulation (NI) high temperature superconductor (HTS) magnet, because the compressive radial stress leads to “good” turn-to-turn contact that is essential for current...
It is well-known that REBaCuO, where RE denotes rare-earth elements, superconducting bulk materials can trap large magnetic field in the compact space. Since REBaCuO bulk materials are subjected to electro-magnetic force, improvements of the mechanical properties of REBaCuO bulk materials are indispensable for the development of high-performance devices. However, conventional REBaCuO bulk...
In designing high field magnets, the enormous mechanical stress on the magnets due to the Lorentz force must be considered. However, the common stress–strain calculations with BJR and/or force balance equation barely considered the frictional force between the superconducting tapes. In this study, the effects of frictional force between these tapes on the stress–strain characteristics were...
REBCO coated conductor (CC) has been applied to high field magnets due to its high critical current density ($Jc$) and high tensile strength. In order to further improve in-field $Jc$, we have developed EuBCO CCs doped BaHfO$_3$ (BHO) as artificial pinning centers (APCs)$^{[1]}$. Since the EuBCO nanocomposite films with the BHO secondary phase is similar to the structure for improving the...
The research and development on the applications of REBCO superconducting coil to the high field magnets for NMR, MRI, accelerator and so on are in progress. In coils wound with REBCO tapes, large screening currents are induced by the radial component of the magnetic field. The magnetic field due to the screening current (hereinafter referred to as screening current-induced field) is generated...
Understanding the human brain in neuro scale is one of the main scientific challenges in the future. The sub-micron Magnetic Resonance Imaging (MRI) is significant to the structural and functional research of the human brain. The important way to improve the resolution of MRI scanner is increasing the magnetic field B_0, as it is well known that the signal to noise ratio (SNR) is proportional...
The Nb3Sn Rutherford cable and composite conductor is developed for 14T Magnetic Resonance Imaging (MRI) magnet project in China. Part of the project is devoted to the Electromagnetic (EM) behaviors studies of the deformed Nb3Sn strands from the cabling process. The magnetization characteristic of deformed Nb3Sn strands by artificial rolling method which simulates the transverse deformation is...
The objective of the magnet design for MRI is first to ensure the field intensity and homogeneity in the central imaging area, and meanwhile to minimize the magnetic leakage of the stray field. Based on this, an optimal design method of 14T actively shielded MRI magnets is proposed in this paper. Firstly the current carrying region of the magnets is subdivided into two-dimensional array grids,...
A 7 T superconducting magnet was designed and under fabrication for animal magnetic resonance imaging (MRI). The magnet includes two primary coils, four compensating coils and three shielding coils. All the coils together produced a homogeneous magnetic field over an imaging sphere with diameter 0.130 m and the stray field was actively-shielded within an area at longitudinal length 3 m and...
We present FEM results of a magnetic design study for 7 T, whole body, actively shielded MRI using Nb3Sn conductor. Nb3Sn strand was used to enable the development of short (1.4 m) segmented coil designs, as opposed to the nearly 2 m long compensated solenoid designs needed for NbTi machines. The use of Nb3Sn strand will allow a conduction cooled design, if quench is properly managed. We...
In superconducting magnetic resonance imaging (MRI) systems, time-varying eddy currents in the conducting cryostat structures are induced by switched gradient coils. These eddy currents increase thermal loads of the cryostat, create acoustic noise, lead to image distortion and limit the application of fast MR sequences. In this paper, a fast coupled circuit network method is employed to...
In magnetic resonance imaging (MRI) system, the magnetic field homogeneity of the imaging area plays a decisive role in the quality of images. Due to assembly errors or the effects of the surrounding ferromagnetic material, the homogeneity fails to meet the design value, which makes the images deformation, and it is necessary to take measures to shim. Passive shimming uses the magnetization of...
The Magnetic Resonance Imaging system(MRI)is an important diagnosis and treatment method of modern medicine. Benefiting from the advancement of superconducting magnet technology, the performance of MRI is continuously improved. In superconducting MRI, the main coils, as the most critical components, greatly determines the quality of images, further affecting the diagnosis. Therefore, the...
In ultra-high field magnetic resonance imaging (MRI) systems, the wavelength of the radiofrequency (RF) field is comparable to the size of imaging object, thus causing complicated coil-tissue interactions, which can lead to detrimental changes of the magnetic field (B1 field) and thermal intensity in human tissue. However, the homogeneity of B1 field and safety is critical for the RF coil,...
We have finalized the design of a full-scale tabletop 1.5-T/90-mm MgB2 “finger” MRI magnet system for osteoporosis screening based on our preliminary test results of small coils and superconducting joints. The magnet will operate in persistent mode at 10 K with an additional 5 K temperature margin. The magnet design satisfies the required specification of a field homogeneity of <5...
This paper presents the design, manufacturing and testing of a 2 + 3 T high field MgB2 ø178 bore solenoid magnet demonstrator (around 55 kgs). The magnet was designed to produce 2 T standalone at 10K and to be operated in a homogenous background field of 3 T. The magnet is helium free and is cooled down by a cryocooler. Three lengths of Columbus MgB2 conductors (1.6 kms) were used to wind the...
Recently, we developed a 0.5-T/300 mm MgB2 magnet using the partial insulation (PI) winding technique that only employs layer-to-layer insulations without the turn-to-turn insulations; the magnet was self-protective but has a significant charge–discharge delay. In this study, the use of Cr-coated MgB2 wires was proposed as an alternative solution to enhance the characteristic resistance of the...
The temporal stability of the magnetic field generated by an MRI magnet is of critical importance for higher resolution medical imaging. However, large screening currents are induced in High Temperature Superconducting (HTS) tapes such as REBCO tapes during the excitation, and attenuated after the excitation due to the flux creep of the HTS tapes. The temporal variation of the magnetic field...
A magnet consisting of five no-insulation (NI) double pancakes (DPs) has been constructed and tested. In this paper, operating currents in each excitation mode were optimized to achieve the highest magnetic field and three excitation modes of the magnet have been conducted in 77 K to compare. Test results showed the central magnetic field increased by multiple sources. Charging performance and...
Generally, MgB2 wires possess a niobium diffusion barrier to prevent an unacceptable reaction between magnesium powder and copper stabilizer. However, given that niobium is costly, extensive studies were conducted to replace the niobium diffusion barrier with iron. Nevertheless, the MgB2 wire with iron diffusion barrier is not yet practically applied to magnetic resonance imaging magnets...
Since UHF MRI offer the possibility to study in a deeper way the brain functionality, these kind of magnets are becoming essential in neuroscience research. ASG is involved in this sector with an active shielded, zero boil-off 7T/700 bore magnet. The magnet with stringent dimensional parameters has been designed and developed by ASG superconductors team for Magnex MS Inc., in order to fulfil...
The radioactive dose rate in the area behind the target of the Super-Fragment Separator (Super-FRS) will be so high that most organic materials will be destroyed in a short period of time. After 20 years of operation an accumulated dose of more than 280 MGy is expected at the most critical parts. Special magnets consisting of radiation resistant materials must be used. Three dipoles, three...
The East Area (EA) is a facility for experiments, beam tests and irradiation operated at the CERN Proton Synchrotron since over 55 years. The experimental area requires high availability, which has been increasingly jeopardized due to the age and reduced reliability of the installed components, in particular magnets and power supplies.
The CERN management has then decided to completely...
The CERN PSB (Proton Synchrotron Booster) is currently under-going a major upgrade with an increase in both injection and extraction energy. With the connection of the new LINAC 4, which replaces the now decommissioned LINAC 2, the energy of the beam to be transported to the PSB is increased from 50 MeV to 160 MeV. Simultaneously, the PSB will be upgraded to provide protons to the CERN PS...
Proton beam is an effective means of radiotherapy for tumors. During the transmission of the proton beam from the accelerator to the treatment head, the direction of the beam is usually changed by the magnetic field generated by dipole magnet. A variety of magnets are arranged in a radiotherapy system using a rotating gantry for proton beam transmission. The 90 degree magnet is placed above...
Proton beams have several features that make them very effective in radiation therapy applications. These include high dose localization as well as high biological effect around the Bragg peak. Moreover, magnetic scanning methods allow one to spread an ion beam to an exact image of a complex tumor shape. The ion scanning system usually consists of two magnets, each scanning horizontal and...
Proton therapy is regarded as one of the most advanced radiotherapy methods for its unique Bragg Peak. As a medical apparatus, the proton therapy facility must deliver stable and accurate dose or proton beams to patients. Huazhong University of Science and Technology (HUST) was funded in 2016 to build such a machine, known as HUST-PTF. The HUST-PTF uses a superconducting cyclotron to produce...
Correction magnets with permanent magnets are investigated. They need to generate both polarities of magnetic fields, which can be realized by rotating permanent magnet rods. Such a magnet system will reduce not only electricity but also maintenance cost. The structure and the field adjustment scheme of a trial conceptual design will be discussed.
Strong magnetic fields are demanded for advanced accelerators. As a cost-effective option other than HTS (High Temperature Superconductors), permanent magnets may be applied in the hybrid magnets to generate the strong magnetic field. One of the most promising permanent magnetic materials for the hybrid magnets is praseodymium permanent magnets (PrFeB). Although the remanent field of...
We prepared a series of 2G HTS wires with systematically varying gadolinium content in the GdBCO layer grown by pulsed laser deposition (PLD) and characterized by them by transport Ic measurements over wide ranges of temperature (T) and magnetic field (H). The samples were fabricated using commercial production equipment at SuperOx and contained different concentration of Gd, starting from the...
REBCO coated conductors (CCs) are promising for high field magnets because of their high in-field critical current density (Jc) performance and high tensile tolerance. To further enhance the in-field Jc, doping artificial pinning centers (APCs) such as BaMO3(M : Zr or Hf etc.) into REBCO film is well known technique. We have developed BaHfO3 (BHO) doped EuBCO CCs using a hot-wall type...
The development of second generation high temperature superconductors (HTS) cable with larger current capacity and lower AC loss are very promising for building fast cycled accelerator magnets. In order to enhance the properties of HTS cable under the different physical fields, several HTS cable structure suitable for magnet application have been proposed by twisting, transposition, stacking,...
High Temperature Superconductors (HTS) are currently considered as promising candidates for high current Cable-In-Conduit Conductors (CICC) for large high-field magnets. In many cases, these CICC are formed from several HTS strands which themselves are formed from individual HTS tapes. These stranding concepts often use stacks of tapes or wrapped-tape arrangements.
Large effort is presently...
Abstract —This paper mainly presents an AC loss numerical calculation of the superconducting strand in AC magnetic fields at 4.2K. Quasi-isotropic strands fabricated by second generation wires are stacked to a center symmetric structure. A 2D simulation model of strands was established based on the finite element simulation software Comsol Multiphysics,from which the distribution of magnetic...
High Temperature Superconductor CrossConductor (HTS CroCo) is manufactured by soldering REBCO tapes of two different widths in a cross-shape form. In a new long length fabrication process, the HTS CroCos are already embedded in solder to obtain a round outer shape. This allows to add an outer copper tube around such an HTS CroCo for increased mechanical and electrical stability. The mechanical...
Superconducting Conductor on Round Core (CORC®) cables with scalability, flexibility, strong mechanical strength and high current density have become practical conductors in high-field magnets for fusion machines and particle accelerators. However, when it works in a high background magnetic field, the high mechanical stresses that generated in the CORC® conductor can result in irreversible...
High temperature superconducting tapes are subject to periodic stresses and strains during AC applications, which may cause performance degradation of HTS tapes. In response to this problem, we built a periodic stress fatigue test platform for HTS tapes, and tested the critical current degradation characteristics of YBCO tapes with two different stabilizing layers under periodic stress. The...
The performance degradation of High Temperature Superconducting (HTS) tape, which may be influenced by various heat exchange conditions due to device structure, is of significant for life assessment of HTS devices under repetitive overcurrent. In this paper, considering stabilizing layer materials and heat exchange conditions, a series of repetitive overcurrent experiments were carried on YBCO...
Abstract-- In order to improve the engineering current density of high-temperature superconducting strand, we developed a kind of quasi-isotropic superconducting strand stacked by 2mm wide REBCO tapes. Minumum quench energy (MQE) and quench propagation velocity (QPV) of quasi-isotropic superconducting strands with copper, aluminum and stainless steel sheaths in liquid nitrogen (LN) were ...
A structural model has been developed for the Cable-in-Conduit Conductor (CICC) made with 2G HTS superconductors inserted in a helically slotted aluminum core (concept proposed by the ENEA Superconductivity laboratory [1]). The cable is particularly suited for high-field applications and consists of a twisted aluminum core and five helical slots. Each slot accommodates a stack of twenty REBCO...
High current superconducting CORC® cable or wire is composed of spiraled HTS REBCO tapes in multiple layers. The cable combines isotropic flexibility and high resilience to electromagnetic and thermal loads. The flexibility of the cable is limited by the critical strain value damaging the REBCO layer in the tape. In order to optimize the manufacture conditions and operating performance, the...
Material scientists have been leading the R&D of coated conductors, and they have been focusing on increasing critical currents and lengths of coated conductors. Thanks to their efforts, long coated conductors with large critical currents are commercially available now. However, when we look back over the history of R&D of low Tc superconductors, stabilization using copper was a breakthrough...
Interconductor contact resistance (ICR) is a key property in determining the stability and current sharing of coated conductor cables. Most coated conductor cables have relatively high contact resistance and low current sharing as fabricated because of surface asperities and the oxide layer that forms on the Cu-stabilizer. Here we work to quantify the induced differences in using three methods...
Spatial homogeneity is one of the most important issues for practical applications of REBCO based magnets. Reel-to-reel Ic measurement is now widely used for the investigation of local Ic variation, however, these measurements are limited at low magnetif field around self-field and at 77 K in most cases, whereas practical operation condistions of superconducting magnets are higher magnetic...
The filamentation of tape shaped RE123-coated conductors is important to reduce the shielding current from RE123 superconducting layer [1] in development of a high-field magnet such as NMR and MRI. In last year, we reported the development of split wire with 16-main-core by electrical separating by bending stress (ESBS) method [2]. In this study, to obtain more main-core, an electrical...
High-temperature superconducting (HTS) tapes are promising materials for developing high-field magnets for fields exceeding 30 T. Therefore, it is important to characterize their properties at high fields, in particular, the critical current, $I_{\rm c}$. One of the promising types of HTS tape is produced by THEVA where the architecture of the tape is unique and simple. Nowadays, these tapes...
High-temperature superconductors are becoming engineering materials, e.g. as commercially available long-length tapes (coated conductors, CCs). Among them, REBa2Cu3O7-x (REBCO, RE rare earth) compounds have emerged as excellent candidates due to their high-field current carrying capacity. Their properties enhance even further when REBCO nanocomposites are formed, i.e., nanoscale...
Due to high flexibilities and high critical current densities, the conductor on round core cable wound with REBCO coated conductors are currently being developed for the next generation of high field magnets. One of the primary challenges in the development of REBCO cable is quench protection, as the cable is prone to be burned out once the quench initiates. However, quench study of REBCO...
A project to develop a Korean-type large scale floating off shore wind power system with a superconducting wind power generator has started. It is an innovative wind power project on the development of high-temperature superconducting (HTS) magnet, test facility, offshore floating system, and network connection technologies for the design of 10 MW class floating offshore wind power system with...
High-temperature superconducting (HTS) materials, including bulks and tape stacks, have shown high current-carrying and field-trapping capacity in previous studies, which makes them employed in the synchronous motors (SMs) as a substitute of permanent magnets (PMs). When used as rotor magnets, hybrid magnets (HMs) made of HTS tape stacks and PMs show remarkable advantages compared with bulks...
Superconducting magnetic levitation (maglev) is developing rapidly in recent decades for its incomparable features like ultrahigh cruising speed. To develop the second generation high tempera-ture superconducting (2G HTS) maglev, a serious of work has been done by us including design of propulsive system, optimiza-tion of 2G HTS magnet system, energizing tests and over-current duration tests....
Linear oscillating machines (LOMs) can control linear reciprocating motions through stroke cycles at specific frequencies. A single-phase, short stroke LOM has been developed for use in refrigeration compressors and other similar devices, because of their high transmission efficiency and simple structure. Generally, conventional LOMs are designed as cylindrical structures. However, such...
Permanent magnet synchronous machines (PMSM) are becoming an essential technology for applications such as home appliances, industrial tools, and electrical vehicles. Todays, consumer demands for noise and vibration of products are increasing, and studies on the noise and vibration characteristics of motors that generate power are actively being conducted. One of the factors contributing to...
In recent years, flux-modulated principle is investigated extensively in diverse permanent magnet (PM) motors due to the prominent advantages of low-speed and large torque capability. And then, a new electrical machine family, nominated as flux-modulated PM (FMPM) motor, is formed gradually. Interestingly, the FMPM motors break through the traditional motor design rule that the pole-pairs of...
This paper presents the research work for a novel dual-stator composite-rotor synchronous machine (DSCRSM). Ferrite permanent magnets (PMs) are used for the composite rotor with flux barriers, while the axis of each PM pole is located as 45 degree (electrical) with respect of the axis of the corresponding flux barrier. Compared with the conventional permanent magnet-assisted synchronous...
Recently, permanent magnet synchronous motors (PMSMs) have been widely used in the industry owing to their various advantages, such as high-speed operation, high efficiency, and compact design. However, PMSMs have the drawback of noise and vibration, which is caused by local force generated by the interaction between the stator and rotor magnets having high magnetic energy, significantly...
Dual mechanical port flux-switching permanent magnet (DMP-FSPM) machine with high power density, high torque density, and wide operation range has potential application prospect in electric vehicles (EVs). The DMP-FSPM machine is consist of inner rotor, outer rotor and middle stator which can be regarded as the combination of two conventional flux-switching permanent magnet (FSPM) machines....
Tubular flux-switching permanent magnet motor (TFSPMM) is a special kind of permanent magnet machine with the permanent magnet (PM) installed on the stator side and there is no winding or PMs on the mover side. Among various kind of linear machines, TFSPMM draws a great interest from researchers for its robust structure, high drive force density and low material cost required. Compared with...
Compared with Linear Induction Motor (LIM) which is widely applied in urban railway transit system, Linear Flux-Switching Motor (LFSM) has the merits of high power density, high efficiency, while the secondary of LFSM is robust and simple. Hence, LFSM is claimed to be promising for urban railway transit system.
Generally, LFSPM can be classified as Linear Wound Field Flux-Switching (LWFFS)...
This paper describes a study on the shape design of Magnetic-geared synchronous Motor for improvement of performance and securing rigidity. The Magnetic-Geared synchronous Motor(MGM) is an all-in-one structure of a magnetic gear and a permanent magnet synchronous motor, and is an electric machinery capable of operating both functions. In this study, the existing surface-mounted type is set as...
1) Introduction
Currently, drones are used in various fields such as logistics, transportation and filming in the military field. However, there is a disadvantage that it is difficult to operate for a long time due to the battery limit of the drone. In order to overcome these disadvantages, studies have been conducted to improve the efficiency of the motor and to increase the power per...
In the past two decades, a bearingless synchronous reluctance motor (BSynRM) was proposed and developed. Besides the advantages of the traditional bearingless motor, the BSynRM has the advantages of simple structure, low cost, low losses and can realize high speed operation using weak magnetic speed regulation. A permanent magnet assisted bearingless synchronous reluctance motor (PMa-BSynRM),...
- Introduction
The BLDC motors(Brushless DC Motors) have been used for different kinds of industries due to the high power density, low maintenance and simple design. BLDC motors are used in variety of applications such as home appliances, electric vehicles and aerospace applications. Recently, aerospace applications like drones raise a demand for a permanent magnet BLDC motor with high...
Permanent magnet (PM) machines have been a research hotspot for EV propulsion due to their merits of high power density and high reliability [1]. Recently, considering the high price and unstable supply of rare-earth PM material, the non-rare-earth PM (NRE-PM) motor has drawn increasing attention. However, the relatively low magnetic energy product of non-rare-earth PM makes it difficult to...
High power motors and generators with compactness and lightweight are required for turboelectric propulsion system for future electric aircrafts. Fully superconducting rotating machines have the potential to realize high power density. In this study, we aim to design high-power-density synchronous motors composed of superconducting field windings and superconducting armature windings,...
High power density motors are required for electric propulsion systems of future electric aircrafts, flying cars and electric vehicles. The highest power density of the conventional motor for aircrafts is reported as 5.5 kW / kg. Superconducting rotating machines have a potential to realize higher power density due to its high current density and low loss property. In this study induction...
EV & HEV are being studied to increase fuel economy and driving efficiency in a variety of ways. Especially, mechanical compressor is critical reason of reducing fuel efficiency. The brushless direct current motor (BLDC) is considered as the most suitable model to satisfy the characteristics of electric compressors. Segmented permanent magnet was used to improve the efficiency of the...
An experimental platform of high temperature superconducting (HTS) synchronous motor with brushless HTS flux pump exciter has been designed and built. The support structure of HTS field windings was designed with a cantilever beam and was manufactured. In this paper, an HTS racetrack coil wound with YBCO tapes was designed and fabricated to verify the reliability of the motor employing a...
Generally, brushless DC (BLDC) motors use three low-cost Hall sensors to obtain information regarding the position of the rotor and operate using a 120° commutation method. Furthermore, BLDC motors require an ideal trapezoidal back-EMF waveform owing to an input current. However, it negatively affects the motor performance owing to the notch phenomenon of current. In addition, torque ripple,...
Linear switched reluctant motors(LSRMs) have received more attention in variable speed drive applications such as urban railway transportation due to their simple structure and minimum use of power switching devices. However, the thrust/power capabilities is not high enough in certain circumstances. To incorporate the merits of simple and robust structure of LSRM and high thrust force density...
Flux-switching permanent magnet (FSPM) machine is extensively investigated own to its advantages of robust motor structure, low torque ripple and high efficiency. Recently, considering the high price and unstable supply of rare-earth PM, less-rare-earth or none-rare-earth PM motors have drawn increasing attention. Due to the relatively low magnetic energy product of non-rare-earth PM, the...
Recently, flux-modulated permanent magnet (FMPM) motors which based on flux-modulation principle have been extensively investigated, due to inherent high torque density at low speed. With the increasingly critical operating environments for traction machines, high-reliability operation of machines has gained much attention. Especially when traction machines operate under extreme conditions,...
Finite Element Method (FEM) modeling of stability and current sharing in Nb3Sn Rutherford cables was performed. The modeled cables had 32 strands and they were three twist pitches long. Different values of contact resistances Ra and Rc were selected based on previous values extracted from ac loss measurements, as well as a set of design values. Current sharing was then projected for these...
The superconducting dipole magnet for the Compressed Baryonic Matter (CBM) experiment at FAIR houses the Silicon Tracking System (STS), and provides a magnetic field integral of 1 Tm which is needed to obtain a momentum resolution of Δp/p = 1% for track reconstruction at FAIR beam energies. The magnet gap has a height of 140 cm and a width of 250 cm in order to accommodate the STS with a polar...
The High Intensity Heavy Ion Accelerator Facility (HIAF) is a new engineering project proposed by Institute of Modern Physics of China. Superconducting magnets will be used as part of the accelerator magnets. When operating at fast-pulsed cycled mode, the superconducting cable will dissipate power (AC loss), which affects the stability of magnet. The main contribution of the AC losses in...
With extremely high critical current density (Jc) and excellent strain tolerance, Nb3Al superconductor is considered as an alternative to Nb3Sn for application of high-filed magnets. However, complexity in the phase formation of Nb3Al hinders the Nb3Al superconducting wires to satisfy the requirement of engineering applications at present. Here, we have reported the improved performance of...
National Institute for Fusion Science (NIFS) in Japan is considering about FFHR-d1 (Force Free Helical Reactor) for their future R&D project. Its magnet system will be needed a pair of helical typed coils with the major radius of 15.6 m. Since the maximum magnetic field on the helical coil of FFHR-d1 reaches 11.9 T, the NbTi cable is not applicable. The practical Nb3Sn cable was selected...
This work compared the phase structure and superconducting properties of RHQT Nb3Al wires fabricated by static and reel to reel (R2R) rapidly heating and quenching conditions. The time for static and dynamic heating of the wire is 0.8s and 0.4s. Rapid heating current (IRHQ) of 67A~69A for static RHQ and 120~122A for R2R dynamic RHQ can fabricated ductile precursor wires and obtain single phase...
In order to develop future particle colliders such as the HiLumi - Large Hadron Collider (HL-LHC) and the Future Circular Collider (FCC), high field superconducting Nb3Sn magnets are necessary. Following the winding, the conductor requires a heat treatment at 650 °C during which significant dimensional changes occur. If dimensional changes are not allowed by the tooling, mechanical stresses...
The advantages of superconducting Rutherford cables are that it can reduce the inductance and increase the stability of superconducting magnets. Due to its high critical field strength and high current carrying capacity Nb3Sn Rutherford cable is one of the best choices for making high field accelerator superconducting magnets. But Nb3Sn superconducting wire has poor mechanical properties and...
U.S. Magnet Development Program (MDP) has developed a 15 T Nb3Sn dipole demonstrator for a post-LHC pp Collider. The magnet design is based on 60-mm aperture 4-layer shell-type coils, graded between the inner and outer layers to maximize the magnet performance. The cable in the two innermost layers has 28 strands 1.0 mm in diameter and the cable in the two outermost layers has 40 strands 0.7...
ABSTRACT BODY:
HTS tapes, because of their widths and large shape aspect ratios, have not been readily manufacturable into Rutherford or Roebel cables, even though these kinds of cables are required for many large coil applications. A type of transposed Roebel cable is under development with 2G tape, but its design flexibility is very limited, and its processing very complex, as well as...
Neurospin is a neuroscience research center located in France at CEA Saclay. The facility is already hosting several MRI magnets and Iseult, an innovative Whole Body 11.7 T MRI system, will be available very soon. The core part of Iseult is an actively shielded NbTi magnet cooled with a superfluid helium bath at 1.8K, that will provide a homogeneous field of 11.7 T within a 90 cm warm bore....
Advanced Conductor Technologies is developing high-temperature superconducting Conductor on Round Core (CORC®) cables and wires wound from REBCO coated conductors for use in high-field magnets. Magnet applications on which the conductor development is focused on include compact fusion magnets that operate at currents between 50 and 100 kA at fields of 12 – 20 T and accelerator magnets that...
Within the US Magnet Development Program (MDP) a 15 T Nb3Sn dipole was developed, to demonstrate a magnet design for a post-LHC pp Collider. The magnet design is based on 60 mm aperture 4-layer shell-type coils, graded between the inner and outer layers to maximize the magnet performance. The cable in the two innermost layers has 28 strands 1.0 mm in diameter and the cable in the two outermost...
Brookhaven National Laboratory (BNL) is building a 25 T, 100 mm cold bore HTS solenoid for the Center for Axion and Precision Physics (CAPP) at the Institute for Basic Science (IBS) in Korea to be used in their search for Dark Matter Axions. The magnet is wound using - Second Generation (2G) High Temperature Superconductor (HTS) tape from SuperPower. The combination of high magnetic field (>20...
F2D2, the FCC Flared-ends Dipole Demonstrator, is a 15 T single-aperture short model being developed within a collaboration between CEA Paris-Saclay and CERN. The design phase is ongoing at CEA; the magnet will be fabricated at CEA and then tested at CERN. The 2D magnetic and mechanical designs have been optimized previously and allowed defining the operating points and the required structural...
The use of REBCO inner coils is a promising option for developing high-field magnets since the coil can be designed at high-hoop stress typically at >400 MPa. Such a coil, however, sometimes suffers from the appearance of a normal voltage even at medium hoop stress such as 200 MPa, i.e., unexpected degradation [1]. We believe that those degradations are caused by strong electromagnetic forces...
Research and development for the practical application of a medical-use magnetic resonance imaging system (MRI) superconducting magnet that requires without liquid helium started as the New Energy and Industrial Technology Development Organization's (NEDO) supported project in fiscal 2016. Development of a liquid helium-free medical MRI superconducting magnet is desired. Another purpose is to...
High field superconducting magnet technology is the key to the success of the high energy particle accelerators. China is pursuing high field magnet R&D for future particle colliders like the Super Proton Proton Collider (SPPC). SPPC will need thousands of high field (12-20 T) superconducting magnets in around 20 years. A long term R&D roadmap of the advanced superconducting materials and high...
Rare Earth-Barium-Copper-Oxide (REBCO) coated conductor (CC) tapes are promising conductors for high energy and high field applications. In the case of epoxy-impregnated REBCO superconducting coils, however, excessive transverse stresses generated from cooling, and Lorentz forces on the CC tapes can cause delamination, resulting in reductions in the load-carrying capacity as well as...
Coils for rare-earth barium copper oxide (REBCO) high temperature superconductor (HTS) magnets are often wound with insulation between turns (i.e. effectively infinite resistance). In this case, magnetic field generated by the coil is linearly related to the transport current in the coil, allowing voltage-limited magnet ramping. However, quench protection has been shown to be hard to...
High field dipole magnets with common-coil configuration are under development at IHEP (the Institute of High Energy Physics, Chinese Academy of Sciences) for key technology pre-study of high energy colliders like SPPC (Super Proton-Proton Collider). A model magnet named LPF1 has been fabricated and tested in 2018, which was made up of 4 flat racetrack NbTi coils and 2 flat racetrack Nb3Sn...
Recently, we developed a superconducting joint between two multi-filamentary Bi2223 tapes with the joint by incongruent melting (JIM) method [1]. During the incongruent melting process, Bi2223 phase is separated to Bi2212, Bi2201, and liquid phases. Since the Bi2212 is also high-temperature superconductor, the superconducting joint can be obtained without recrystallization of Bi2223 from the...
In this study we performed magnetic, mechanical and thermal modeling of a 3T actively shielded whole body MRI (Magnetic Resonance Imaging) magnet. The final design had an overall magnet length and conductor length which can lead to conduction cooled designs which are comparable to NbTi helium bath cooled 3 T designs. The design had a magnetic field homogeneity better than 10 ppm...
For realizing HTS magnets equipped with a persistent current circuit, the development of superconducting joints between HTS tapes with enough large current capacity in external magnetic fields is indispensable. On the other hand, the Ag-sheathed Bi2223 (Bi2223/Ag) commercial tapes, DI-BSCCO, show high critical current (Ic) characteristics of ~ 200 A at 77 K in self-field and...
In this paper, we present construction and persistent-mode operation results of a half-scale 1.5-T/54-mm room-temperature bore MgB2 MRI-quality magnet for the development of a tabletop “finger” MRI system. A half-scale magnet, composed of 5 coil sections and a persistent-current switch, was wound with a single ~590-m long unreacted/monofilament MgB2 wire having a...
New high temperature superconductor (HTS) technology is actively being pursued to achieve fields beyond those available with the present Nb3Sn technology (~23 T). In an effort to further drive Bi2Sr2CaCu2O8-δ (Bi 2212) round wire technology, better understanding of the performance of coils wound with this conductor is paramount. Work presented in this body demonstrates that the limiting strain...
This paper presents the design of a high field and portable MRI magnet system for the rapid and early diagnosis of brain trauma. Early diagnosis and therapy stratification can reduce the risk for critically brain ill patients with the use of near patient imaging, and can aid with precision medicine. High temperature superconductors have the ability to carry large currents at higher...
This paper reports a design and performance estimation of a 20 T no-insulation (NI) high temperature superconductor (HTS) standalone user magnet currently being developed at the National High Magnetic Field Laboratory. It consists of a stack of 17 double pancake coils wound with tapes from two different vendors, SuNAM and SuperPower, in consideration of their complementary in-field critical...
This paper presents our analysis of the electromagnetic characteristic and thermal stability of 2G high-temperature superconductor (HTS) pancake coils depending on the turn-to-turn contact resistance. Numerical simulations for investigating electromagnetic characteristic, mechanical stress and thermal stability of HTS pancake coils were performed by taking into account different contact...
This article analyzes the charging behavior of no-insulation high temperature superconducting (HTS) ReBCO double-cake coils under conduction cooling and liquid nitrogen cooling in detail. A partial equivalent circuit model of a determined parameter ReBCO coil is applied to evaluate charging behavior under different cooling conditions. At the same time, the finite element method is used to...
This paper is to study the practical critical current of No-insulation (NI) high temperature superconducting (HTS) coils under local heat disturbances. Based on a multi-physics model that built from an electric network model, a thermal coil model and a magnetic field model, behaviors of a HTS coil under different currents and heat disturbances are compared in this paper. A balance model of HTS...
The no-insulation (NI) method has provided dramatic progress on the high-field magnet technology in the last decade. An NI REBCO pancake coil can operate at a very high current density supported by a self-protecting behavior. However, it was recently demonstrated that asymmetric distributions of axial forces due to electromagnetic forces during the quench propagation results in serious...
Recently, we have reported that screening currents in REBCO high field magnets may be a source of large electromagnetic stresses and consequently cause mechanical damage to the superconducting tape. To better estimate the electromechanical behavior of a REBCO magnet even in the initial design stage, we have modeled the distribution of screening currents in an NI REBCO magnet and compared the...
Due to the special rectangular cross section of the REBCO tapes, the screening current-Induced magnetic field (SCIF) in a REBCO high temperature superconducting (HTS) coil will deteriorate the spatial homogeneity and temporal stability of the superconducting magnet, which is a key issue for the application of HTS magnets in the Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging...
The NHMFL has commenced with the development of an all-superconducting 40 T magnet that will be installed in its DC-Field User Facility. At present various high temperature superconductor technologies are being investigated as candidates for the magnet construction. It is the objective of this early development stage to address questions regarding the application of a type of superconductor...
Tokamak Energy are developing large scale REBCO HTS magnets for application in spherical tokamaks for fusion energy. As part of our HTS technology development plan, a series of quality assessment (QA) coils have been manufactured and tested. These are non-insulated coils containing ~100 m of HTS tape. The manufacture and testing of these magnets has allowed us to assess the performance of HTS...
The National High Magnetic Field Laboratory (NHMFL) has successfully operated its 20 Tesla 195mm large bore magnet for over 20 years. Eventually, as there was a certain slowdown in demand for that magnet at the time, it had been decommissioned in 2016 and its two outer coils have been re-used for parts in a higher energy density configuration to facilitate the fast construction of the word...
The High Field Magnet Laboratory of the Radboud University is cons