Analysis And Design Of The Large-scale Static Magnetic Field Coil System For Immunity Test

The high-intensity static stray magnetic field of the large tokamak fusion devices will lead to the failure of the electrical and electronic apparatus,which becomes a potential threat to the reliable operation of tokamak devices.Magnetic field immunity test is the main technical method to perform the access qualification of the apparatus.The large-scale static magnetic field coil is the core component of the immunity test system,which is mainly used to generate the required large-scale high-intensity homogeneous magnetic field.In order to perform the magnetic field immunity tests for the apparatus of China Fusion Engineering Test Reactor(CFETR),a 2.1 m/500 m T static magnetic field immunity test platform is planned to be developed under the program of Comprehensive Research Facility for Fusion Technology(CRAFT).Since the scale and field intensity of the CRAFT test coil are large and the design parameters are the first in the world,its design and development lack of reference.In addition,the total electrical power and conductor mass of the test coil are high,and thus the low-power and low-weight optimization design and multi-physics coupling analysis are of vital importance,the prototype development is also a challenge.This dissertation focuses on the research of the analysis and design of the large-scale static magnetic field coil.The main contents are as follows:(1)Aiming at the limited space of the homogeneous magnetic field of the traditional coil system,the optimized coil configurations and their normalized mathematical models for magnetic field immunity tests were proposed.Based on a comprehensive definition of the homogeneous magnetic field,the normalization design method of the coaxial coil was studied,and the optimized coil configurations were proposed.Further,several groups of practical design formula were proposed,and a performance improvement of 11.5%～24.8%was achieved compared with the traditional Merritt coils.(2)Aiming at the low-power low-weight optimization and other design requirements of the large-scale high-intensity immunity test coil system,a fast and elitist non-dominated sorting genetic algorithm based optimization design method was proposed,and the optimization design of the CRAFT 2.1 m/500 m T test coil was implemented.The general constrained multi-variable and multi-objective optimization model of the large crosssectional test coil was established.The influence of the coil structural parameters on the Pareto-optimal front was studied,and the optimization design of the CRAFT coil was implemented.Further,aiming at the operation stability and such issue of the large-scale high-intensity test coil,the multi-physics coupling analysis and engineering design including electromagnetic,thermal,and structural of the CRAFT test coil were implemented.(3)Based on the static magnetic field test facility procurement project of the International Thermonuclear Experimental Reactor(ITER)organization,a 1 m/275 m T test coil was developed and tested,which owns the highest comprehensive test parameters in the world.On the basis of the optimization design and engineering analysis,the ITER test coil was developed.Further,the magnetic field distribution,the resistance and inductance characteristic,and the temperature rise were tested.The experimental outcomes verify the effectiveness of the optimization design method and the key techniques.(4)The new design scheme of the test coil based on the magnetic enhancement of the ferromagnetic material was explored,which provides an innovative idea for the low-power and low-weight design of the test coil.The magnetic field analytical model of the test coil under ferromagnetic boundary was established through multi-reflection theory,and the design method based on magnetic enhancement was proposed.The analysis indicates that the ferromagnetic material can improve the magnetic field generation efficiency by 175.4%,and reduce the total electrical power by 84.1%,even considering the weight of the ferromagnetic material,a reduction of 43.4% can be achieved.The research work of this dissertation has laid a solid foundation for the development of the CRAFT large-scale static magnetic field coil,and also provides references for the analysis and design of such coils.In addition,it also provides valuable guidance for the optimization design and engineering analysis of other high-power large-volume magnet systems.