【作者】 潘仙林；

【导师】 陆祖良； 王祁；

【作者基本信息】 哈尔滨工业大学 ， 仪器科学与技术， 2013， 博士

【摘要】 建立四端电阻时间常数标准是实现交流阻抗准确测量及交流电量计量量值统一的关键，同时也是目前国际上在脉冲电流和宽频功率研究方向的热点问题。早在二十世纪初,国际上提出了几种特殊结构设计的计算样品，而样品中等效电感计算往往涉及到复杂的电磁场理论，且计算结果受样品本身结构尺寸测量准确性的影响而引起较大的不确定度。随着测量技术和仪器仪表的不断发展，国际上开始采用测量的方法直接对四端电阻的正交分量进行绝对定值，然而仪表误差及容性泄漏等影响是制约测量准确性的主要因素。目前，国际上普遍采用step-up（爬台阶）法来实现四端电阻量程扩展，该方法中所存在的串联“浮地”影响、测量仪表线性误差及多步传递所造成的不确定度累积是主要的影响因素。本论文工作回归问题的本质，灵活地应用了精密电磁测量中的替代法，针对准确测量四端电阻时间常数若干关键技术进行了深入研究。针对目前已有测量仪表无法满足在较大水平分量下直接准确测量四端电阻等效电感的问题，本文采用了结构替代法，即在相同结构下，将自行研制的“同轴拉线”结构四端电阻中高电阻率电阻丝替换成低电阻率电阻丝，从而减少了水平分量对正交分量所引起的影响，便于测量。为了进一步减少测量仪表的影响，本文研制了Q值高的四端互感，并深入分析了该互感结构中寄生电容、残余电感及引线电阻等参数的影响，采用电流电压转换法实现对互感的准确测量。采用替代法将四端电阻等效电感与已知的互感进行相互比较，将其溯源至我国已有的交流电压和交流电流国家标准，从而准确测量四端电阻中微小正交分量，确定该四端电阻的时间常数，为四端电阻量值传递提供了溯源依据。针对四端电阻串联连接时低端电位不一致而受有源仪表“浮地”影响而引起容性泄露误差的问题，本文采用二进制感应分流器的方法实现两路共地电流输出。详细分析了二进制感应分流器受比例绕组的激磁误差、容性误差及外接负载误差的影响，提出了电流一致性自校验的实验方法，同时研制三级感应分流器级联结构实现三路共地等电流输出，为四端电阻相互比较时提供了准确且关系已知的电流。针对目前国际上普遍采用step-up方法实现电阻量程扩展中存在的多步传递而引起测量不确定度累积的问题，本文采用电压比例技术，将不同阻值的四端电阻在相同电流下进行等电压测量，通过一步传递实现量程扩展。深入分析了二进制感应分压器和串并联结构电阻分压器的参数模型，并对其电压比例的相角偏差进行了自校验。结合二进制感应分流器和电压比例技术，建立四端电阻量值传递装置，满足1A~100A四端电阻时间常数和相角偏差的溯源需求。本文采用该传递装置对实验室自行研制的10m~1鼠笼结构四端电阻、100A互感式电流电压变换器和薄膜结构四端电阻的相角偏差进行了准确测量，其相角测量标准不确定度在200kHz频率下优于100μrad。针对四端电阻在传递过程中测量电流和工作电流不一致而引起的电流系数问题，本文采用三种不同类型的四端电阻1A~100A电流范围进行相互比较，评估了四端电阻相角偏差的电流系数。因此，所建立的四端电阻时间常数标准和量值传递装置，实现了高频大电流四端电阻相角偏差的准确测量，也为我国今后建立宽频交流功率电能国家基准奠定了基础。更多还原

【Abstract】 The establishment of time constant and phase angle standard of four-terminalresistors is the key technology to achieve the reunification of the ac impedance andac quality metrology, and also has become focus in establishment of ac current andac power standard. In the early twentieth century, several special structurecalculable samples have been designed. The equivalent inductance of thosesamples often involves complicated electromagnetic calculation, and accuratemeasurement of structure dimension will bring large uncertainties for thedetermination of inductance. With the development of the measurement techniqueand instruments, different methods to measure the quadrature part of the shuntshave been proposed at international metrology institutes, and the accuracy of theinstruments and the capacitive leakage errors become the main influence source.The conventional step-up method is widely used to realize the ranges extension forcurrent shunts by many steps comparisons, and will cause uncertaintiesaccumulation. Besides, float state in the series connection and linearity effectsneed to be considered in measurement procedure. Aiming at solving thoseproblems, the essence of the precise measurement named substitution method isflexibly applied to the establishment of phase angle standard of current shunts.According to the existed problem that the equivalent inductance of thefour-terminal resistor is unable to be precisely measured directly with largein-phase part, a structured alternative method has been developed. Based on themethod, a coaxial paralleled design resistor is built with high-resistivity wires andreplaced with low-resistivity wires at the same structure, to reduce the in-phasepart of the resistor. In order to reduce the influence of the measurement instrument,a high Q-value mutual inductor has been designed and analysized deeply its maineffect from structure parameters like parasitic capacitance, residual inductance andwire resistance. By meaning of current-voltage conversion method, the mutualinductance can be measured accurately and used as the impedence standard at highfrequency. Using alternative method, the equivalent inductance of the resistor canbe compared with known mutual inductor, and calibrated against the Ac voltageand current national standards. The time constant of the resistor can be determinedand provide traceability for phase angel errors measurement.With traditional in-series floating connection, the low-terminal potentialinconsistences between two resistors cause capacitive leakage for activemeasurement instruments, especially at high frequency. In order to reduce the leakage errors, a binary inductive current divider (BICD) has been developed togenerate two currents and to compare the two impedances with highly accuracy atcommon ground. The BICD has been studied deeply, and its influences from theexcitation windings errors, capacitive leakage and external loads are consideredand comprehensive evaluated. Basen on the BICD, a three-branch BICD has alsobeen designed. To calibrate the phase angle errors between two currents of theBICD, the method based on difference current transformer has been proposed.In the uncertainty budget of a step-up procedure, the accumulation of manysteps is very often the dominant part, especially at currents up to100A. To reducethis influence, a new range extension setup is built by comparing two differentresistors with only one step based on the voltage proportional technology. A binaryinductive voltage divider (BIVD) with ratio2:1and resistive voltage divider (RVD)with series and paralleled structure have been constructed, used as the phase anglestandard with ratio10:1and100:1. The structure model of the BIVD and RVD hasbeen analysized deeply and the phase angle errors have been also intensivelyconsidered and self-calibratedby. In combination with the BICD and voltageproportional technology, a new setup for range extension with highly measurementaccuracy is developed and meets traceability requirements for measuring timeconstant and the phase angle of the1A to100A four-terminal resistors.Based on the new setup, several lab-made cage like shunts from1to10m and an inductive current-to-voltage converter is measured against time constantstandard. In additional, a metal-foil structure shunt with10m resistance has alsobeen precisely calibrated and the relative uncertainty is estimated to be less than100μrad at200kHz. The phase angle errors of the high current shunts aremeasured at the current level of1A, instead of the normally rated currents of100A, so the level dependence in phase angle errors of the high current shunts is quitecrucial. A method of evaluating the level dependence in phase angle errors of thehigh current shunts at currents from1A to100A has been developed. The timeconstant standard of current shunts is applied to meet the traceability demand ofphase angle errors and also lay the foundation for establishment of high frequencynational power standard in future.更多还原