报告题目：AC loss issues in all-superconducting rotating machines for aircraft applications
报告时间：2023年12月18日，10:30
报告地点：信息学馆228室
报 告 人：Prof. Zhenan Jiang （姜哲男 教授）
新西兰维多利亚大学罗宾逊研究所
邀 请 人：杨东升教授 李硕讲师
个人简介：
Zhenan Jiang (Senior Member, IEEE) received a B.Eng. in Electrical Engineering from Chongqing University in Chongqing, China in 1994, and M.Eng., Ph.D. Eng. in applied superconductivity from Yokohama National University in Yokohama, Japan in 2002 and 2005, respectively.
He was a Postdoctoral Research Fellow at Yokohama National University from 2005 to 2008. He joined the Superconductivity Group currently known as the Robinson Research Institute at Victoria University of Wellington, New Zealand in 2008 as Research Scientist. He has a strong track record in characterization of high temperature superconductors (HTS), especially in AC loss. He has an h – index of 35 and more than 3500 citations. He is now Professor in the institute and leading AC loss research in the institute. His recent research interests include AC loss characterization in HTS, HTS applications including transformers, flux pumps, magnets, and rotating machines.
Prof. Jiang has been twice awarded the JSPS (Japan Society for the Promotion of Science) invitation fellowship to Kyoto University, in 2011 and 2015, respectively. From 2021, he became an editorial board member of an Elsevier journal, Superconductivity. He was awarded the 2021 Scott Medal from Royal Society New Zealand for his work on measuring and modelling the response of superconductors.
报告内容：
Electric propulsion for aviation requires high power density and light weight all-superconducting motors and generators. However, superconductors in the armature windings of rotating machines carry AC currents under rotating magnetic fields and large AC loss generated in the armature windings poses a great challenge for the cooling system. Therefore, AC loss reduction in superconducting armature windings is one of critical tasks to underpin the application. Obvious conductor choices for the armature windings are REBCO coated conductors and multifilamentary MgB2 wires. However, YBCO wires may not be the best suitable choice due to their limitation in achievable filament size and difficulty in twisting the filaments. On the other hand, MgB2 wires operating at 20 K are promising for the armature windings. The filament size can be as small as 10 mm which can result in considerable hysteresis loss reduction. Twist pitches have been demonstrated as low as 5 mm, and the copper can be moved, compared to DC MgB2 wires. However, coupling loss in the normal conductors in the MgB2 wires might be the dominant loss component for the application due to the high operating frequency. Therefore, one of urgent tasks is to accurately estimate the AC loss in the MgB2 wires at actual operating conditions. There have been some analytical equations developed for AC loss estimations in MgB2 wires. However, the analytical equations have not been validated by experimental results. Furthermore, the analytical equations have limitations for complex wire compositions and operational conditions. Therefore, we need experimental AC loss data in the MgB2 wires operating under real operating conditions and simulation tools which are validated by experiment and can be extended to predict AC loss for more complicated wire structure and operating conditions which cannot be achieved by experiment.
