Optimizing coil configurations for AC loss reduction in REBCO HTS fast-ramping magnets at cryogenic temperatures  

作　　者：Zhenan Jiang Honghai Song Wenjuan Song Rodney A.Badcock 

机构地区：[1]Robinson Research Institute,Victoria University of Wellington,Wellington,New Zealand [2]Department of Physics and Astronomy,State University of New York at Stony Brook,New York,USA [3]James Watts School of Engineering,University of Glasgow,Glasgow,UK

出　　处：《Superconductivity》2022年第3期133-142,共10页超导（英文）

基　　金：supported in part by New Zealand Ministry of Business,Innovation and Employment(MBIE)by the Strategic Science Investment Fund“Advanced Energy Technology Platforms”under Contract RTVU2004;2020 Google Excellence Research University Program;US DOE Ernst Courant Traineeship in Accelerator Sciences and Engineering,the educational program of next generation of accelerator physicists and engineer,US Department of Energy,HEP office.

摘　　要：AC loss is one of the critical issues for designing REBCO fast‐ramping magnets operating at cryogenic temperatures.There are many ways to reduce AC loss for coil windings.However,it is not clear which method is the most effective way to minimize AC loss in the coil windings for a given Ampere‐turns.In this work,we numerically studied coil configurations of several small superconducting magnets constructed from 12 mm SuperPower REBCO coated conductors,for fast‐ramping application with the same Ampere‐turns to identify the lowest AC loss among them.The HTS magnets have a total turn number of 50 and inner diameter of 30 cm,carrying AC current operating in the temperature range of 20–40 K at 25 Hz.We incorporated several existing loss reduction strategies including spacing between the turns for single pancake coils,grading Ic values for the solenoid configuration,and applying flux diverters to shape the magnetic field around the coil windings.The simulation was implemented using a homogenized H‐formulation.Across all studied loss reduction methods,the use of flux diverters has the largest impact in AC loss reduction.The AC loss values in the solenoid winding comprising a stack of five single pancake coils with 0.1 mm turn‐to‐turn gap with the flux diverters agree well with those in the single pancake coil for 2 mm turn‐to‐turn gap with the flux diverters.Solenoid type coil configurations with flux diverters generate much smaller AC loss than the single pancake type with flux diverters when they generate the same center magnetic field.

关 键 词：Fast ramping magnet AC loss reduction H‐formulation REBCO Flux diverters 

分 类 号：TM26[一般工业技术—材料科学与工程]