This paper studied the alternating current (AC) loss of stacked high-temperature superconducting (HTS) tapes based on the finite-element method (FEM). By solving the partial differential equation (PDE) of H formulation, this research analyzed the effects of the frequency, amplitude and phase of the current and magnetic field on the AC loss of the three-layer stacked HTS tapes which works under...
AC loss reduction in HTS coils can help reduce the cryogenic demands and increase the performance of HTS machines. In an HTS coil, most AC loss is generated in the end windings due to the large radial magnetic field in these parts. Therefore, one of the effective methods to reduce AC loss in HTS coils is using ferromagnetic flux diverters to reduce the radial components of the magnetic field...
Electric machines have been applied to every industrial and transport applications today and are required to realize high-output density.
Superconducting technology is one of the most effective methods for realizing the high-output density motors. The superconducting coils at ultra-low temperature can energize several hundred times higher current density in comparison with copper wires; it...
Rare earth barium copper oxide (REBCO) coated conductors (CC) have high thermal stability and high current density. REBCO CCs are suitable for generating high magnetic fields. It is expected that magnets wound with REBCO CCs are utilized for high magnetic field applications, such as magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR), medical-use accelerators, and compact...
No-insulation (NI) high-Tc superconducting (HTS) coils process much higher thermal and electrical stability than the conventional insulated coils. In some rotating machines and Maglev trains, HTS coils carry persistent current and serve as the permanent magnets. For these applications, the main issue is that the demagnetization of HTS coils caused by the local external alternating fields. This...
As is well known all types of superconductors are affected by AC losses.
Those losses occur when a time varying current flows in a superconductor or when it’s subjected to a variable magnetic field.
The main effect of these losses on the conductor is temperature rise due to the energy dissipation within the superconductor. Many methods were previously studied in order to reduce the magnitude...
High temperature superconductor (HTS) coil has superior current-carrying ability, and can trap higher magnetic fields, thus shows a promising application on machines with super high power density. Winding coils with bare tapes without any insulation, which is called no-insulation (NI) coil, can significantly enhance the thermal stability and reliability of HTS coils. However, in many...
In order to examine the applicability of superconducting technology to fields of industrial applications such as linear conveyor, transfer, and transport systems, we investigated AC loss characteristics of HTS sample coils under conditions assumed for use in power electronics devices. Since inverters are used in the drive circuit of power electronics devices in a linear transfer system and so...
Nb3Al has better the strain properties than that of Nb3Sn, but it is difficult to manufacture as a wire. In recent years, a research group of the National Institute for Materials Science (NIMS) in Japan has developed a new shape of ultra-fine and flexible Nb3Al superconducting. Jelly-rolled Nb/Al composite monofilamentary wires with an outer diameter of 30 m, and multi-strand wires were...
