Distribution of Trapped Magnetic Flux in Superconducting Stacks Magnetised by Angled Field

Lukasz Tomkow,Anis Smara,Vicente Climente-Alarcon,Bartek A Glowacki

doi:10.1007/s10948-019-05375-3

Abstract

Some novel energy applications require the use of complex shapes of stacks of superconducting tapes as trapped-flux magnets. A trapped-flux magnet magnetised in a superconducting motor may experience an angled magnetising field rather than a field normal to its surface. This will affect the trapped magnetic flux distribution. This work presents the results of the numerical and experimental analyses of the stacks magnetised in an angled magnetic field. The finite element model using H-formulation is developed to compute the induced superconducting currents. The measurements are performed on stacks with different thicknesses and with different orientations against a magnetising field. The resulting distribution of the magnetic flux as well as the electric currents is computed, presented and discussed in details. The importance of the observed distribution patterns is assessed in the context of the implementation of such stacks in a fully superconducting electric motor.

Highlights

Stacked superconducting tapes can be applied as a very efficient trapped-flux magnet
Thin stacks maintain the direction of the flux perpendicular to the surface in a wide range of angles of magnetising field
The total trapped flux becomes weaker with the increase of the magnetising field angle

Summary

Introduction

Stacked superconducting tapes can be applied as a very efficient trapped-flux magnet. Induction values as high as 17.7 T were achieved [1]. Simplicity and high thermal stability, they can outperform bulk superconductors in some applications with pulse magnetisation [2]. It is proposed to apply such magnets in a rotor of a superconducting synchronous motor for an aircraft [5]. The major advantage of the application of superconductors in an aircraft motor is the increase of power to weight ratio, achievable by using the superconducting stator windings [6, 7]. Other applications that may benefit from the decreased weight of the motors are marine propulsion [8] and wind turbines [9]

Methods

Results

Conclusion