稳态磁场交流阻抗测量系统及其电磁兼容研究

发布时间：2018-03-13 15:33

本文选题：交流阻抗测量　切入点：PPMS　出处：《华中科技大学》2014年博士论文　论文类型：学位论文

【摘要】：同时具有磁有序和铁电有序的多铁性材料具有广泛的研究价值以及技术应用前景。因此,此类材料的磁电耦合特性受到研究者的广泛关注。另外,交流阻抗测量能够探索材料内部的微观结构以及导电机制,对磁电耦合特性材料的研究具有重要意义。因此设计并搭建了一个基于稳态磁场的交流阻抗测量系统,用以探索材料学领域中的相关问题。本文主要研究内容如下：介绍交流阻抗测量的原理以及基本公式,在此基础上给出介电常数的计算方法以及Cole-Cole圆的绘制方法。介绍测量系统的基本组成,给出各部分模块及设备的连接方式、功能型号、性能参数。逐一分析了在整个测量过程中遇到的问题,针对性地提出了样品杆的设计方案。研究行驻波对测量结果的影响以及传输线参数的变化原理。讨论精密阻抗分析仪的高频补偿校准无法通过的原因以及解决方法。建立基于多导体模型的4+1传输线模型。在不同的屏蔽层假设条件下,计算了单位长度传输线的参数并针对测量系统提出预测。实际测量结果与预测吻合,验证了电路模型的正确性。最后,对模型进行了电场与磁场仿真。根据测量系统可能受到的电磁干扰途径,将测量系统划分为供电电源、精密阻抗分析仪、腔外传输线、样品杆连接座、腔内传输线、样品座六个部分。将这六个部分的传导干扰以及辐射干扰问题分别进行了详细的研究。针对共模、差模干扰问题以及开路、短路下的负载电路特点,进行了干扰路径建模以及公式推导。根据测量系统的特点给出检测电磁干扰信号的方法以及测量信号的频谱分析。详细地介绍了屏蔽层的连接方法与样品电极的制作方法与关键技术。验证测量系统的电磁兼容可靠性。结合硬件系统介绍了软件系统的结构,分析了精密阻抗分析仪以及PPMS工作时的软件运行特点,然后详细介绍软件系统中的存储算法、数据通讯算法、数据同步算法。以程序界面为例展示软件系统的使用方法以及运行流程。文章最后给出了基于频率、磁场、温度等物理量的测量数据,根据给出公式绘制出介电常数曲线和阻抗Cole-Cole圆,论证了测量系统的搭建效果,并对实验结果进行了分析。
[Abstract]:At the same time with multiferroic materials with magnetic order and ferroelectric research value and wide application prospect of technology. Therefore, magnetoelectric coupling properties of these materials has attracted the attention of researchers. In addition, AC impedance measurement can explore the internal microstructure and conductive mechanism, it is important to study the magnetoelectric coupling properties of materials therefore, to design and build an AC impedance measurement system based on steady-state magnetic field, using the related issues to explore in the field of material science. The main research contents of this paper are as follows:
The principle and basic formula of AC impedance measurement are introduced. Based on that, the calculation method of dielectric constant and the drawing method of Cole-Cole circle are given. The basic composition of measurement system is introduced, and the connection modes, function models and performance parameters of each module and equipment are given.
Analyze the encounter in the whole measurement process problems, puts forward the design scheme of sample bar. Effects of traveling wave on the measurement results and the change of transmission line parameters of the principle. Discuss the causes of high frequency compensation calibration precision impedance analyzer cannot pass and solution. The establishment of 4+1 model based on multi conductor transmission line model. Assuming the shielding layer under different conditions, the calculation parameters of the unit length of the transmission line and the measurement system is presented to forecast. The actual measurement results are consistent with the prediction, show the correctness of the model. Finally, the model of the electric field and magnetic field simulation.
According to the way of electromagnetic interference measurement system may be the measurement system will be divided into power supply, precision impedance analyzer, transmission line cavity, the sample rod connecting seat, cavity transmission line, a sample of six parts. The six part will be conducted interference and radiated interference problems were studied in detail. According to the common mode. Differential mode interference and open circuit, short circuit of the load circuit, the interference path modeling and formula. According to the features of this method of signal detection of electromagnetic interference measurement system and spectrum measurement signal analysis. This paper introduces the method of making connection method and sample electrode shielding layer and the key technology of electromagnetic verification. The measurement system is compatible with reliability.
Introduces the structure of software system with hardware system, analyzes the precision impedance analyzer and the PPMS software running characteristics of the work, then the storage algorithm is presented in detail in the software system, data communication method, data synchronization algorithm. The program interface as an example to show the usage of the software system and operating processes.
At last, the measurement data based on frequency, magnetic field, temperature and other physical quantities are given. Based on the given formula, the dielectric constant curve and the impedance Cole-Cole circle are plotted. The effectiveness of the measurement system is demonstrated, and the experimental results are analyzed.

【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM934.73

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