【作者】 邵海明；

【导师】 张钟华；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2010， 博士

【摘要】 《国家中长期科学和技术发展规划纲要》将新能源开发、节能减排等列入重点领域和优先发展主题,对产业进行统筹安排、规划布局。计量科学研究需要紧密服务国家战略,为经济和社会可持续发展、自主创新科学研究提供强有力的计量校准和量值溯源支撑。直流大电流与一系列大量消耗电能的工业生产,如冶金、化工、电镀、电动汽车充电和直流输电等密切相关,准确测量直流大电流可为节能减排提供基础数据;核物理、高能物理科学研究中也需要进行准确的直流大电流测量、控制和校准。因此,研究和建立高准确度的直流大电流比例国家计量标准,是满足有关工业和科学实验对直流大电流和比例计量溯源的重要技术基础。本论文研究得到了国家科技部科技基础性工作专项“国家现代电学计量标准和检测体系的建立与完善”（项目编号:2003DIA7J035）之“直流大电流测量技术研究”课题（合同编号:0404GY-2）支持,主要研究在实际工作状态（工作磁势和漏磁势）下高准确度直流电流比较仪（DCC）自校准的方法和装置。论文主要研究了DCC自校准、磁屏蔽、母线优化、性能测试和不确定度评定等理论、技术和方法,自主创新提出了一种“分布式的均匀化空间磁势法”大电流DCC设计和自校准理论,并将之应用于系列DCC设计、研制和校准中,完成了一套直流大电流比例自校准装置,量程10A:1A～5kA:5A,自校准的测量不确定度1×10^-8～2.6×10^-7,k=2,到达国际领先水平,解决了高准确度DCC在额定磁势和实际工作条件下的比例自校准问题。本文紧紧围绕解决大电流DCC在实际工作状态下的高准确度比例自校准问题开展研究,在以下方面取得了卓有成效的成果:1.首次提出了“分布式的均匀化空间磁势法”高准确度大电流DCC设计、制造和自校准理论,较好地解决了大电流母线引起的强磁场干扰,实际研制的装置的实验结果证明了该理论的正确性和有效性。2.提出和证明了一种在实际工作状态（工作磁势和漏磁势）下的直流电流比较仪（DCC）高准确度自校准新方法——“串并联法”;推导了“串并联法”的比例公式,证明了该比例的相对偏差极限小于各绕组等效匝数（就产生等效磁势而言）相对差的最大值和并联时流过各绕组电流相对差的最大值之积。结合采用刚性固定母线、并联均匀分流等技术,实现了大电流DCC在实际漏磁状态下高准确度自校准。3.基于磁路法,推导了带气隙磁屏蔽效能的理论计算公式,得出:存在气隙时,竖直方向的磁屏蔽效能劣于水平方向;气隙的厚度决定了磁屏蔽的综合磁屏蔽效能,与磁屏蔽厚度和磁导率关系不大。以研制的5kA:5A DCC的参数为例,电磁场数值仿真值和解析值一致性良好。4.基于无定向结构原理,采用电磁场数值分析法,在仿真分析一次偏心母线在检测铁芯中产生的漏磁场特点的基础上,提出并仿真证明采用偶数、对称分布式排列的一次偏心母线和返回导体结构,可以实现DCC铁芯和磁屏蔽中空间磁势的均匀化分布,大幅度减小漏磁影响;进而研究了一次母线匝数,窗口半径和形状的影响,给出了优化的母线布置、结构和参数设计方案。5.综合采用优化的母线设计、气隙控制和双层磁屏蔽等技术,完成了一次母线具有串并联结构的大电流DCC研制,以及实际工作状态下的高准确度“串并联法”比例自校准。6.采用FEM分析法,分析了一次母线不同反极性串联方式在铁芯中的漏磁,得出采用“间次反极性串联法”评估一次母线产生的干扰磁场对DCC不确定度的影响更符合实际。7.建立了“串并联法”DCC自校准的不确定度评估数学模型,在实际测试DCC磁势非线性、漏磁影响等基础上,完成了测量不确定度估计和验证。更多还原

【Abstract】 New energy development, energy-savings and emissions reduction were emphasized and listed as priorities in the“The Outline of the National Program for Long- and Medium-Term Scientific and Technological Development”. These industries will generally be planned by the State. Metrology Science is closely connected with the national strategy and provides powerful support for metrology calibration and traceability. This allows for development and sustainability of the economy and society, and innovation in scientific research.High amperage direct current measurement technology is widely used in industries such as metallurgy, chemical engineering, electroplating, electrical vehicle charging station, DC power transmission, and many others. High-accuracy measurement of high amperage direct current can provide the basic data for energy-savings and emissions reduction. It is also critical to measure, control, and calibrate high amperage direct current in scientific research of nuclear physics and high energy physics. Research and development for a high-accuracy high amperage direct current ratio national standard is the critical technical basis of high amperage direct current and ratio traceability in industries and sciences in the country. In this research, the self-calibration method and apparatus of the high-accuracy Direct Current Comparator （DCC） under working state, that is working and leakage megnetomotive forces, are developed. The research was funded by the project of“Research in Measuring High Amperage Direct Current”（Contract No. 0404GY-2）, the sub-project of“Setup and Improvement of Electrical National Standard and Calibration System”（Project No. 2003DIA7J035）, that is a basic research project under the Ministry of National Science and Technology.In the research, the theory and method of the DCC self-calibration, magnetic shielding, bus layout, performance testing, and uncertainty budget were developed, a set of theory of designing and self-calibrating the high-accuracy high amperage DCC, which is named of a method of distributed and uniformized space magnetomotive force, was self-renovation proposed and applied to the development and calibration of a series of DCCs. A self-calibration apparatus of high amperage direct current ratio was developed, with ranges of 10 A: 1 A to 5 kA: 5 A. The measurement uncertainty （k=2） of self-calibration is from 1×10^-8 to 2.6×10^-7, which is the best specifications according to the mastered information. The problem of ratio self-calibration of high-accuracy DCC under rated magnetic potential and working state was solved successfully.The research focused on the accurate ratio self-calibration of high amperage DCC under working states, and highly fruitful results are summarized as follows:1. The theory of designing, fabricating and self-calibrating the high-accuracy High Amperage DCC, a method of distributed and uniformized space magnetomotive force, was first put forward, and the strong magnetic interference introduced by large current buses is reduced. The experiment results on a developed apparatus confirmed that the theory is correct and effective.2. A new series and parallel method using primary windings with the same nominal turns connected in series or parallel for DCC high-accuracy self-calibration was proposed. The ratio equation of“series and parallel”method was deduced. It is proved that the relative deviation limitation is smaller than the product of the maximum difference among equivalent turns of windings （producing equivalent magnetic potential） and the maximum difference among the current over parallel windings. By combing with rigid-fixed bus bars and uniformized parallel currents technologies, the high-accuracy self-calibration of high amperage DCC under magnetic leakage was accomplished.3. A theoretical equation to calculate the effectiveness of magnetic shielding with air gap was deduced based on magnetic circuit method. It is concluded that magnetic shielding effectiveness in the vertical direction is worse than that in the horizontal direction; the comprehensive magnetic shielding effectiveness is determined by the thickness of the air gap and not affected by the thickness of magnetic shielding and permeability. The good agreements between the electromagnetic numerical simulation value and analytical value were achieved by using the 5kA:5A DCC developed as an example.4. Through electromagnetic numerical analysis based on the Astatic Structure Principle, it is proposed that using even and symmetrical eccentric buses and returning conductors can uniformly distribute space magnetomotive force inside of the detecting cores and magnetic shielding, and reduce dramatically the influence of magnetic leakage in the basis of simulating and analyzing the magnetic leakage characteristics produced by an eccentric bus in the detecting magnetic core. Furthermore, the bus layout, structure and parameters design were optimized after the influences of bus winding number, window radius, and shapes were analyzed.5. Using the series and parallel method and combining the optimized technologies of bus design, air gap control, and double magnetic shielding, high amperage DCCs with“series and parallel”structure in their buses were developed and high-accuracy series and parallel ratio self-calibration under working states was carried out.6. Through analyzing the magnetic leakage of the buses in the detecting core under different series connections using FEM analysis method, it is concluded that the method of“one by one in opposed series”is better for evaluating the influence to the uncertainty due to magnetic interference introduced by the buses.7. A mathematical model for the uncertainty budget of DCC self-calibration using series and parallel method was established. In the basis of practically measuring the non-linearity on magnetic potential and influence of magnetic leakage et al, the measurement uncertainty was estimated and verified.更多还原