Numerical modelling of dynamic resistance in high-temperature superconducting coated-conductor wires
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In this paper, a 2D numerical model based on the finite element method and implementing the H -formulation is used to calculate the dynamic resistance and total AC loss in a coated-conductor HTS wire carrying an arbitrary DC transport current and exposed to background AC magnetic fields up to 100 mT.Abstract:
© 2018 IOP Publishing Ltd. The use of superconducting wire within AC power systems is complicated by the dissipative interactions that occur when a superconductor is exposed to an alternating current and/or magnetic field, giving rise to a superconducting AC loss caused by the motion of vortices within the superconducting material. When a superconductor is exposed to an alternating field whilst carrying a constant DC transport current, a DC electrical resistance can be observed, commonly referred to as 'dynamic resistance.' Dynamic resistance is relevant to many potential higherature superconducting (HTS) applications and has been identified as critical to understanding the operating mechanism of HTS flux pump devices. In this paper, a 2D numerical model based on the finite-element method and implementing the H -formulation is used to calculate the dynamic resistance and total AC loss in a coated-conductor HTS wire carrying an arbitrary DC transport current and exposed to background AC magnetic fields up to 100 mT. The measured angular dependence of the superconducting properties of the wire are used as input data, and the model is validated using experimental data for magnetic fields perpendicular to the plane of the wire, as well as at angles of 30° and 60° to this axis. The model is used to obtain insights into the characteristics of such dynamic resistance, including its relationship with the applied current and field, the wire's superconducting properties, the threshold field above which dynamic resistance is generated and the flux-flow resistance that arises when the total driven transport current exceeds the field-dependent critical current, I c( B ), of the wire. It is shown that the dynamic resistance can be mostly determined by the perpendicular field component with subtle differences determined by the angular dependence of the superconducting properties of the wire. The dynamic resistance in parallel fields is essentially negligible until J c is exceeded and flux-flow resistance occurs.read more
Citations
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Loss characteristics of HTS coated conductors in field windings of electric aircraft propulsion motors
TL;DR: In this paper, the authors examined the dynamic and total loss characteristics of YBCO-coated conductors in the frequency range relevant to high-speed motors for electric aircraft propulsion.
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Total loss measurement and simulation in a REBCO coated conductor carrying DC current in perpendicular AC magnetic field at various temperatures
Yueming Sun,Yueming Sun,Jin Fang,Gennady Sidorov,Quan Li,Rodney A. Badcock,Nicholas J. Long,Zhenan Jiang +7 more
TL;DR: In this paper, the authors measured the total loss in a 4 mm wide REBCO coated conductor under perpendicular AC magnetic fields up to 105 mT at 77 K, 70 K, and 65 K, with reduced DC current level, i (I dc/I c0), from 0.025 to 0.98, where I dc is the transport DC current value and I c0 is the self-field critical current of the coated conductor at each temperature.
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Numerical Modelling of Dynamic Resistance in a Parallel-Connected Stack of HTS Coated-Conductor Tapes
Justin M. Brooks,Mark D. Ainslie,Zhenan Jiang,Stuart C. Wimbush,Rodney A. Badcock,Chris W. Bumby +5 more
TL;DR: In this article, the authors present a finite element method (FEM) analysis of both the time averaged dynamic resistance and the instantaneous current sharing behavior in a cable comprised of a stack of four YBCO thin films connected in parallel.
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Optimizing Rotor Speed and Geometry for an Externally Mounted HTS Dynamo
TL;DR: In this paper, the effects of varying either the rotor speed or the number of magnets arranged symmetrically upon the rotor were examined for axial-flux HTS dynamos, employing an externally mounted rotor carrying m permanent magnets.
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