An Improved Self-Consistent Model and Its Application to Estimate the Critical Current of REBCO Magnet

Abstract

There is a growing interest in using HTS magnet to improve the performance of the electric devices such as motor/generator, NMR/MRI and EDS train. For the HTS magnet, the critical current is of importance since it determines the current-carrying capacity, i.e., the ability to generate magnetic field. So, it is imperative to estimate the critical current of HTS magnet. However, the numerical modelling of the magnet is not straightforward due to the field-dependent critical current density, a large number of turns and the ultra-high aspect ratio, e.g., of REBCO (REBa2Cu3Ox, where RE = Rare Earth) coated conductor. To make the estimation of the critical current accessible, this paper aims at developing an improved self-consistent model. First, the analytical expressions of the self-field of a generalized racetrack magnet are derived from the Biot-Savart's law. Secondly, the self-consistent model is introduced and validated by comparing the estimated critical current of a racetrack REBCO magnet with the measured one. Thirdly, based on the homogenized technique, the efficiency of self-consistent model is significantly improved with accuracy preserved. Lastly, we estimate the critical current of a generalized racetrack REBCO magnet for EDS train use with the improved self-consistent model.