2017). AC losses in HTS coils for high-frequency and nonsinusoidal currents. Superconductor Science and Technology, 30(9), [095006]. https://doi.Abstract-AC losses in racetrack coils that are wound of YBCO tapes are measured for sinusoidal and non-sinusoidal transport currents with fundamental frequencies up to 1 kHz. An electrical method to measure losses for non-sinusoidal currents is developed for this purpose. The measured losses are compared to the losses calculated by 2D finite element models with power-law material models. The frequency and waveform-dependency of the measured losses are shown, and compared to the results of the models over a wide range of frequencies and waveforms. Finally, it is shown that the finite element models can accurately predict AC losses resulting from non-sinusoidal transport currents as are present in highly dynamic motors with AC armature coils.

No abstract

No abstract

DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:

This paper presents a numerical modeling method for AC losses in highly dynamic linear actuators with high temperature superconducting (HTS) tapes. The AC losses and generated force of two actuators, with different placement of the cryostats, are compared. In these actuators, the main loss component in the superconducting tapes are hysteresis losses, which result from both the non-sinusoidal phase currents and move ment of the permanent magnets. The modeling method, based on the H-formulation of the magnetic fields, takes into account permanent magnetization and movement of per manent magnets. Calculated losses as function of the peak phase current of both super conducting actuators are compared to those of an equivalent non-cryogenic actuator.

The T-A formulation has proved a fast and reliable method for the evaluation of AC losses in superconducting tapes, and has been successfully applied to complex geometries such as racetrack coils, CORC® cables, and twisted stacked tapes conductors in either applied magnetic field or self-field. In particular the T-A formulation was used for the evaluation of AC losses in CORC® cables made of striated superconducting tapes in an external applied field, with a null transport current. In this paper, the T-A formulation is adopted to evaluate the AC losses of stacked striated HTS tapes, representative of the straight section of a racetrack coil, with a sinusoidal transport current.

Abstract-This paper concerns the requirement analysis and implementation of a measurement instrument which can identify the 3D magnetostriction strain. To measure magnetostriction, a high-accuracy magnetic flux density and strain measurement are required, while the mechanical stress in the sample is minimized. The Full Block Tester (FBT) is proposed as a measurement instrument. In this instrument, homogeneity of flux density within the measured sample and the strain measurement resolution are sufficient, but stress caused by magnetic forces is higher than required.

No abstract