【作者】 杨迪；

【导师】 林君；

【作者基本信息】 吉林大学 ， 仪器科学与技术， 2024， 硕士

【摘要】 宽频电流比例技术在精密电磁计量领域中占据十分重要的地位,如在交流电流、交流功率以及低值交流电阻器的准确测量等研究领域,须借助高精度的电流比例才能顺利进行。而在一些非电参数测量中,宽频电流比例的作用更加显著,在测量中大量使用的各种类型传感器和应变器,实质上是靠宽频电流比例变化来确定被测量的。多元感应分流器（MICD）作为一种特殊结构的电流比例,具有工作频带宽,准确度高且易于校准,能实现大电流测量等优势,是目前可自校的准确度最高、频带最宽的电流比例标准。中国计量科学研究院研制了应用于高频电流测量的单级MICD,并设计了测差变压器法实现分流器误差的自校准,可实现音频范围内甚至100 k Hz范围内交流电流的精密测量。但该分流器在低频下的误差增大,且校准方法存在测差变压器绕组残余阻抗使参考支路的电位与其他支路不等,在低频时感抗不够高等问题,因此需要进一步开展适用于更低频率的宽频带MICD研制及自校准方法的研究。针对以上问题,本文开展MICD设计及误差校准方法研究,在分析了MICD结构原理和误差来源的基础上,提出了N支路的双级MICD和电子式感应分流器设计,研制了11支路MICD,并提出了基于等电位法的MICD误差校准方法,设计了校准系统对研制的感应分流器误差在20 Hz～1000 Hz范围内进行校准,并对校准结果进行了不确定度评估。本文研究内容主要包括以下几点:第一,详细分析了MICD的结构原理和误差来源,提出了双级MICD和电子式MICD设计,提高了分流器等效输入阻抗,大大减小了支路阻抗不匹配引入的误差;第二,研制了11支路MICD,给出了铁心选型及绕组设计方案,重点提出了支路电阻一致性原则,以减小各支路阻抗引入的误差,最后提出了MICD建立电流比例的方法,用于实现交流电流精密测量;第三,提出了基于等电位法的MICD误差校准方法,解决了校准过程中被测两支路电位不一致的问题,进一步提高了误差校准的精度,尤其是低频下的MICD误差校准精度;第四,搭建了基于等电位法的MICD误差校准系统,研制完成各关键核心模块,在20 Hz～1000 Hz范围内实现了MICD误差的自校准,并对校准结果的不确定度进行了分析。本文针对MICD这一电流比例技术展开了研究,提出了双级和电子式MICD的设计,并提出了基于等电位法的误差校准方法,减小低频条件下校准过程中由于支路电位不一致引入的误差,研制11支路MICD,在20 Hz～1000 Hz范围内比例误差不超过1μA/A,不确定度在10^-7量级;相角误差不超过3μrad,不确定度在10^-6量级。更多还原

【Abstract】 Wideband current ratio technology in the field of precision electromagnetic measurement occupies a very important position,such as in the AC current,AC power and low value AC resistor accurate measurement.In the measurement of some non-electrical parameters,the role of wide-frequency current ratio is more significant,and various types of sensors and strain gauges used in the measurement are essentially determined by the change of wideband current ratio.Multiple induction current divider（MICD）as a special structure of the current ratio,with a wide operating band,high accuracy and easy to calibrate,can achieve the advantages of large-current measurement,etc..It is the current ratio standard with the highest accuracy and the widest frequency band that can be self-calibrated.The National Institute of Metrology,China,has developed a single-stage MICD for high-frequency current measurement and designed a differential transformer method to achieve self-calibration of the current divider error,which can achieve precision measurement of AC current in the audio range and even in the 100 k Hz range.However,the error of this divider increases at low frequencies,and the calibration method has the problems that the residual impedance of the differential transformer winding makes the potential of the reference branch unequal to that of the other branches,and the inductive impedance is not sufficiently high at low frequencies,therefore,it is necessary to further carry out the development of a wide-band MICD suitable for lower frequencies and the research of self-calibration method.Aiming at the above problems,this paper carries out the research on the design of MICD and the error calibration method.Based on the analysis of the structural principle of MICD and the source of error,it proposes the design of two-stage MICD with N-branch circuit and electronic induction current divider,and develops 11-branch MICD,and puts forward the MICD error calibration method based on the equipotential method,and designs the calibration system to calibrate the developed MICD error in the frequency range of 20 Hz～1000 Hz,and the uncertainty of the calibration results is evaluated.The research content of this paper mainly includes the following aspects:Firstly,the structural principle and error sources of the MICD are analyzed in detail,and the design of a two-stage MICD and an electronic MICD is proposed,which improves the equivalent input impedance of the current divider and greatly reduces the error introduced by the branch impedance mismatch.Secondly,an 11-branch MICD is developed,the core selection and winding design scheme are given,the principle of consistency of branch resistance is highlighted to reduce the error introduced by the impedance of each branch,and finally,the method of establishing the current ratio of the MICD is proposed for the realization of precision measurement of AC current.Thirdly,an error calibration method based on the equipotential method for MICD is proposed,which solves the problem of the inconsistency of the potentials of the two branches under test during the calibration process,and further improves the accuracy of the error calibration,especially the accuracy of the MICD error calibration at low frequencies.Fourthly,a MICD error calibration system based on the equipotential method has been constructed,the key core modules have been developed,the self-calibration of the MICD error has been realized in the range of 20 Hz～1000 Hz,and the uncertainty of the calibration results has been analyzed..In this paper,the current ratio technology of MICD is investigated,the design of two-stage and electronic MICD is proposed,and the error calibration method based on the equipotential method is proposed to reduce the error introduced by the inconsistency of the branch potentials in the calibration process under the low-frequency condition,and the 11-branch MICD is developed and tested in the range of 20 Hz～1000 Hz,and the ratio error is no more than 1μA/A and the corresponding uncertainty is in the order of 10^-7,The phase angle error does not exceed 3μrad,and the uncertainty is in the order of 10^-6.更多还原