【作者】 李前；

【导师】 毛承雄； 陆继明；

【作者基本信息】 华中科技大学 ， 电力系统及其自动化， 2005， 硕士

【摘要】 直流大电流测量是现代电测量技术的重要内容。随着直流用电负荷的越来越大,对直流大电流测量也提出了更高的要求。本文结合国家自然科学基金项目——多路罗柯夫斯基直流大电流智能化传感器研究而展开工作。在综合了解直流大电流测量的背景、意义、发展现状及直流大电流各种主要测量原理的基础上,本文选择对直流调制比较仪原理进行深入研究,为直流大电流传感器的开发建立良好的理论基础。在深入研究铁芯线圈电路和调制直流测量原理的基础上,本文研究磁性材料的磁特性,确定钼坡莫合金磁粉芯作为调制用环形磁芯,使用Matlab 软件,建立了铁芯磁化曲线的数学模型,同时利用Simulink 工具对单铁芯和双铁芯直流调制器进行了结构建模与仿真。仿真模型充分考虑激励线圈、偏磁线圈、检测线圈各自内阻的影响,利用电压源作为激励信号,可以精确模拟磁化曲线的饱和段、快速直观的研究调制器的工作原理和各个参数对调制器的影响,弥补传统作图法的不足; 可以指导设计具有最佳工作特性的调制器。通过对仿真结果的分析,本文提出了利用感应线圈正负半波有效值差随直流偏磁变化的这个特征量构建调制比较仪测量直流电流的新思路。最后,本文通过构建实验平台,对单铁芯和双铁芯直流调制器进行电压源激励开环实验,验证了调制器仿真模型的正确性; 通过真有效值闭环比较仪实验,初步验证了利用正负半波有效值差这个特征量来制作调制比较仪测量直流大电流的可行性。更多还原

【Abstract】 Heavy direct current (DC) measurement is a very important part of modern electric measurement. With more and more direct current power absorption, it is very urgent to develop the methods and instruments for heavy DC measurement to meet such requirement. This treatise is ground on the item of National Natural Science Fund “the research of multiplex Rogowski coils intelligent heavy DC sensors”. According to our comprehension on the main principia of heavy DC measurement, we determine to study the theory of DC modulation comparator., for making a good foundation in theoretically and experimentally. After lucubrated the electrocircuit of magnetic core and the method of modulation comparator, we founded the simulation model of the magnetization curve and the modulation comparator under the environment of MATLAB SIMULINK to study the principle of magnetic modulation comparator. The model can exactly simulate the saturation of B-H curve of permalloy core. The model takes into account the influence of the self-resistance of stimulation winding, direct winding and measurement winding. The presented method can give great help to know the principle of magnetic modulation comparator, which also is important to design the comparator with satisfactory performance. On the other hand, According to the simulation result, we brought forward a new measurement scheme by comparing the difference of the output wave’s virtual value from the detect coil. In order to validate the simulation model, we carry out a feasible experimentation. By analysing the result ,we arrive at a conclusion that the simulation model of the magnetization curve and the modulation comparator is accurate ,also the new method of DC measurement we brought forward is basically viable.更多还原