Pulsed field magnetization of multiple bulks used as field pole of a high-temperature superconducting rotating machine

An array of three GdBa_(2)Cu_(3)O_(7‐δ)bulk high‐temperature superconductors(HTS)that mimic the field pole of a high‐power superconducting motor had been magnetized by pulsed field magnetization(PFM)while cooled by liquid nitrogen.The bulk array was magnetized by a passive PFM technique using three vortex‐type coils placed over each individual bulk and connected in series.The trapped magnetic flux density distribution was comparable to the distribution obtained with more traditional quasi‐static magnetization such as field‐cooling.This suggests that the use of PFM technique on arrays of HTS bulks is possible.PFM has also been performed using each coil individually,to magnetize each bulk sequentially.The magnetization sequences showed a maximum reduction of the peak trapped magnetic flux density of 12%due to the demagnetization effect of the magnetization sequence,while the trapped magnetization distribution was improved.

Concept design of an HTS linear power generator for wave energy conversion

We show a conceptual structure for a wave energy converter,which features a direct‐drive linear power generator with REBaCuO high‐temperature superconducting(HTS)bulk field poles and driven by a heaving buoy.A dual translator power generation system of the proposed concept structure is a linear generator in which both the HTS bulks and armature copper coils move in opposite directions simultaneously.A performance analysis of our linear generator was conducted using a finite‐element electromagnetic field analysis method.The results of the analysis were compared between the HTS dual translator linear power generator and the HTS single translator linear power generator.The maximum electromagnetic force and the average output power of the HTS dual translator are around 5%and 11%higher than that of the HTS single translator.We further present the results of the analysis regarding the influence of reducing the stroke length of the linear generator translator on the output power,where the output power for the HTS dual translator system increased up to a factor of two,in comparison to the HTS single translator counterpart,for the same reduction of stroke length.