An air-core higherature superconducting quadruple magnet (AHQM) is composed of higherature superconductor (HTS) coils without an iron yoke. An AHQM exhibits magnetic field characteristics that vary linearly with respect to changes in the operating current. Further, the AHQM is more suitable for use in high heat load regions. A conventional iron-core quadruple magnet (IQM) contains an iron yoke to achieve the specific shape and magnitude of the magnetic field. In the case of IQMs, the iron yoke generates most of the magnetic field. In the case of AHQMs, the magnetic fields are generated solely by HTS coils. Thus, an AHQM requires a larger number of coils to generate a magnetic field, because the iron yoke has been removed. Consequently, the influence of manufacturing errors in the AHQM is high; these errors deteriorate the designed magnetic field. Therefore, magnetic field correction is required to reduce the deterioration in the magnetic field of an AHQM. This paper, proposes a novel active shim method to compensate for the deteriorated magnetic field of an AHQM. This method improves the uniformity, but does not affect the gradient and effective length of the quadruple magnet. The effectiveness of this method is verified by simulation.
Bibliographical noteFunding Information:
Currently, our research team has been working on a project supported by the National Research Foundation of Korea to design an air-core high-temperature superconducting quadruple magnet (AHQM) that replaces LTS wires with HTS wires, and removes the iron yoke from the ILQM , . The AHQM was designed based on the magnetic field characteristics of the quadruple magnet required by the IBS. To examine the performance and characteristics of the AHQM designed in previous paper, we compared it with the IHQM . In Fig. 1, the shapes of the designed AHQM and IHQM are displayed. The designed AHQM can also solve the high heat load problem exhibited by ILQM. The magnet exhibits a linear magnetic field characteristic that varies according to the operating current, because the iron yoke with its nonlinear magnetization characteristics is removed. However, to compensate for the lack of the magnetic field that would have been generated by the iron yoke, the AHQM requires more wires and coils than the IHQM. The more the number of coils used in the magnet, the more the influence of manufacturing errors on the magnetic field characteristics.
Manuscript received October 30, 2018; accepted February 14, 2019. Date of publication February 28, 2019; date of current version April 4, 2019. This work was supported in part by “Human Resources Program in Energy Technology” of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea, and in part by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) under Grants 20184030202270 and 2017R1A2B3012208. (Corresponding author: Tae Kuk Ko.) J. Kim, G. Baek, and T. K. Ko are with the School of Electrical and Electronic Engineering, Yonsei University, Seoul 30722, South Korea (e-mail:, firstname.lastname@example.org).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering