【作者】 吕以亮；

【导师】 李亮；

【作者基本信息】 华中科技大学 ， 电气工程， 2013， 博士

【摘要】 强磁场作为一种极端条件，对物质的作用效果明显，已成为现代科学研究中越来越重要的工具。强磁场可分为稳态强磁场和脉冲强磁场，稳态强磁场持续时间长，但设备和运行成本高，且磁场强度相对较低。脉冲强磁场磁场强度高，但是持续时间短，无法满足某些科学实验的要求，且短脉冲条件下信号的测量较为困难。长脉冲强磁场结合了脉冲磁场磁场强度和稳态磁场持续时间上的双重的优势，能进一步拓展强磁场在科学上的应用，具有重要的科学意义。目前常用的脉冲强磁场电源包括电容器储能电源和脉冲发电机型电源。电容器储能密度较低，场地和成本投入大，因此更适合驱动短脉冲磁体。脉冲发电机电源能量大，且可控性好，但是控制复杂，且输出纹波难以去除。而蓄电池电源能量大，且输出为直流，不存在纹波问题。本文提出采用蓄电池组作为长脉冲强磁场的电源。论文首先对铅酸蓄电池脉冲高倍率放电进行了理论与实验研究。测试了铅酸蓄电池的脉冲高倍率放电极限性能，对放电的电流、电压以及内阻等关键参数进行了实际测试。随机选取一只蓄电池进行了持续性放电，以测试其对脉冲高倍率放电的承受能力，进一步验证蓄电池组脉冲电源建设的可行性。脉冲磁体是脉冲强磁场装置的核心。结合蓄电池脉冲放电参数，作者进行了长脉冲磁体与电源的组合优化研究。针对长脉冲磁体最为关键的温升问题，分析了磁体形状和体积与磁体温升之间的关系，揭示增大体积降低温升的方法和电源容量之间的矛盾关系。结合蓄电池供电电路进行了脉冲磁体的电、磁、热多物理场耦合分析，研究温升导致的参数变化对放电过程和磁场波形的影响，提出通过控制磁体温升改善长脉冲磁场波形的方案。根据本文长脉冲磁体设计理论，优化设计了一套40T长脉冲磁体和电源方案。由于长脉冲磁体电源电压低，电流持续时间长，导致导体截面积增大，带来了磁体结构设计和加工上的问题。本文引入水冷磁体的helix线圈结构，并根据脉冲磁体的特点对helix线圈结构进行了改进。将水冷通道改为优化了的层间加固，并将线圈端部闭合回路切开以避免感应涡流所带来的电磁力。脉冲磁体能否正常工作以及所能达到的最高磁场强度指标，很大程度上取决于磁体加工制造过程，工艺上的任何一点小缺陷都有可能导致脉冲磁体的破坏或寿命缩短。针对helix内线圈在加工、绝缘、加固以及组装等环节上的问题，本文都提出了相应的解决办法。对铜皮外线圈的电极焊接以及绕制过程也进行了详细的介绍。作者在国家脉冲强磁场科学中心(筹)完成了整套长脉冲强磁场装置的建设和调试工作。本文还将对整个装置系统的构成以及其他关键部件进行介绍，并给出电源和磁体的最终测试结果。在长脉冲强磁场系统的基础上，作者还进行了高稳定度长脉冲强磁场实现方法的探讨。通过磁体和电源的组合或施加一些辅助手段，可以达到更高稳定度的长脉冲强磁场。本文对几种方式的可行性以及所能达到的磁场稳定度水平进行了相应的介绍。更多还原

【Abstract】 High magnetic field, as a kind of extreme condition, has become a more and moreimportant tool in modern scientific research. High magnetic field is divided intocontinuous high magnetic field and pulse high magnetic field. The continuous highmagnetic field can last for a long time, but the investment and operation cost is very high,also the field intensity is low. The pulse high magnetic field has high field intensity, butthe field can only last for a very short time. It can’t satisfy some of the scientific research,besides, the signal acquisition is relatively difficult in short pulse magnetic field. Longpulse high magnetic field combined the advantages of field intensity and lasting time, canimprove the use of high magnetic in scientific research.The pulsed power system used in WHMFC consists of parallel capacitor banks andpulsed generator. As a low energy density storage system, the capacitor banks arenormally used for generating short pulsed magnetic field. Although the pulsed generatorhas a high energy density and good control characteristics, it always suffers from thecomplex control method and high harmonic interference output. Compared with the twopower system referred before, the battery bank has the merits of high energy storage, DCcurrent output and no harmonic interference. Hence, a battery bank is adopted as thepower of the pulsed magnetic field.Firstly, the pulsed discharge characteristics of the battery bank are studied in theoryand experiment. The pulsed discharge characteristics of the lead-acid battery are measured,including the current, voltage and the resistance. The experiment results certificates thedesign well.The pulsed magnet is the key of the pulsed magnetic field facility. Based on thepulsed discharge parameters of the battery, the author has done a study about long pulsedmagnets and the optimization of the power supply. For analyzing the most critical problemof temperature rise in the long pulsed magnets, the relationship between the magnettemperature rise with the magnet shape and volume, revealed the contradictoryrelationship between the volume increases to reduce the temperature rise and the capacityof power supply. And Combined with the battery-powered circuit, the author conducted a pulse magnet electric, magnetic, thermal multi-physics coupling analysis, analyzed theinfluences of temperature rise resulting from the parameter change on the dischargeprocess and the magnetic-field waveform. Proposed to improve the long-pulsed magneticfield waveform by controlling the magnet temperature rise, the final magnet optimizationprocess is to seek the optimum configuration relationship between the power supplycapacity and the magnetic field strength and pulse width.According to the design theory of the pulsed magnetic field, a40T long pulsedmagnet system is designed. Due to the large volume of the pulsed magnet, it is difficult instructure design and manufacturing. This paper presents an optimized helix magnet coil,which has inner distribution reinforcement instead of cooling channel and a slit in the endsof the coil in order to avoid the electromagnetic force induced by the eddy current.The manufacture process of the magnet is very important because it often decideswhether the pulse magnet can work properly and the highest magnetic field intensity it canreach. Any small defect in the process may cause damage or shorten the life of a pulsemagnet. This paper has proposed solutions for problems existing in the processing,insulation, reinforcement and assembly process of the Helix inner coil. And the electrodewelding and the winding process of the outer copper coil are also described in detail.The author has completed the construction of the long pulse high magnetic fielddevice at Wuhan National High Magnetic Field Center. The composition of this apparatussystem and other critical components are desired in this paper, and the final test results ofthe power and magnet are also given.Based on the long pulse high magnetic field system, the author has also discussed themethod for building high stability long pulse high magnetic field, which can be realized bythe combination of magnet and power or imposing some auxiliary means. Comparison onthe feasibility and stability level between several methods has been made in the paper.Finally, the author summarizes these studies and discussed on further improvementand development of the magnets and power.更多还原