An Axial Gap-Type HTS Bulk Synchronous Motor Excited by Pulsed-Field Magnetization With Vortex-Type Armature Copper Windings

Abstract

We studied a high-temperature superconducting synchronous motor assembled with melt-textured Gd-Ba-Cu-O bulk field magnets. The motor is an axial gap-type, brushless synchronous motor with eight rotating bulk field magnet poles. Liquid nitrogen is circulated to cool down the rotor components. Pulsed field magnetization was performed to excite the bulk field magnets by using a pair of the vortex-type armature copper windings under the zero-field cooling. The trapped peak field density on the surface of the bulk was varied from 0.5 T to 0.8 T. The trapped peak magnetic field 0.5 T on the surface of the bulk magnets provided the motor performance of 3.1 kW with 720 rpm. The field density distribution on the pole bulk magnet surface is anisotropic and different from the ideal conical shape. The optimized pulsed current waveform applied to the armature and the employing of a composite of bulk crystal magnets leading to a spatially homogeneous flux trapping are promising methods for reinforcement of the field flux from the rotor and the motor torque.Index Terms-High-temperature super-conducting motor, hightemperature superconductors, melt-processed bulk superconductors, melt-textured Gd123.

Microstructure and superconducting properties in air-properties GdBa2Cu3O7-δsuperconductor with the additives of nano particles

“…Large single-domain RE-Ba-Cu-O superconductors are promising materials for cryogenic applications due to their superior superconducting performance [1,2,3]. For the commercialization, it is important to keep the low cost to fabricate while being the high superconducting properties.…”

“…The corresponded nano-sized inclusions and defects in the superconducting matrix are effective as pinning centers to improve J C of melt-growth bulk superconductors REBa 2 Cu 3 O 7-δ (RE123) [4][5][6][7][8][9]. It is reported that the additions of nano-sized SnO 2 or ZrO 2 to RE123 matrix, as second phase with Gd211 inclusions, form a three-dimensional band structure to enhance J C [8]. Lau et al observed that the Ag-sheathed Bi(Pb)-Sr-Ca-Cu-O tapes with magnetic nano-powder γ-Fe 2 O 3 increase the pining strength [11].…”

Applied HTS Bulks and Wires to Rotating Machines for Marine Propulsion

“…A small-size synchronous machine with Gd-123 bulk-HTS pole-field magnets aimed at the sub-MW class of ship propulsion motors has been constructed in 2002. The evaluation test was conducted in 2003, and a 3.1 kW output with 720 rpm was reported [4]. On the other hand, the machine designed with the Bi-2223 HTS winding offers the convenience of increasing the magnetic flux as a function of applied DC current.…”

Evaluation of magnetic force distribution on a pair of superconducting bulk magnets

“…Since the bulk magnet can generate strong magnetic field exceeding 2 T that is the limit of ordinary iron-cored electromagnets by compact device in a low running cost, various industrial applications such as motor/generator [2], magnetron spattering [3], drug delivery system (DDS) [4] and magnetic separation [5,6] are considered. To propagate an industrial application of bulk magnet in the feature, it is necessary to enhance a magnetic force, as well as amplitude of magnetic field.…”