摘要
提出了一种基于数字比例技术的高精度交流电桥设计,该电桥能在100 Hz^100 kHz频率范围内实现四端对标准电阻、电感及电容的高精度比较测量。提出的新型高隔离度模拟开关电路能在保证电桥测量精度的前提下,提高电桥的测量速度。桥路的负反馈环路能克服数字信号源的有限分辨率对电桥的平衡时间和平衡精度影响,进一步优化测量过程。基于电桥的分布参数模型,分析了电桥在平衡过程中所产生的泄露电流对数字比例的影响,并提出修正方法。该数字交流电桥在1 kHz频率下测量两路矢量电压典型幅值比的标准不确定度可达6μV/V,相位差标准不确定度10μrad,在典型频率与量程范围内的阻抗量值相对测量不确定度优于3×10-5(k=3)。
A high-precision AC bridge design based on digital ratio technology is proposed.The bridge can realize high-precision comparative measurement of standard resistance,inductance and capacitance with four terminal pair definition in the frequency range of 100 Hz to 100 kHz.The newly designed high isolation analog switch circuit in the bridge can improve the measurement speed of the bridge under the premise of ensuring the measurement accuracy of the bridge.The bridge negative feedback loop can overcome the influence of the limited resolution of the digital signal source on the balance time and balance accuracy of the bridge,and further optimize the measurement process.Based on the distributed parameter model of the bridge,the influence of the leakage current generated by the bridge during the balancing process on the digital ratio is analyzed,and a correction method is proposed.The standard uncertainty of the typical amplitude ratio of the two vector voltages measured with the digital AC bridge at a frequency of 1 kHz can reach 6μV/V,the standard uncertainty of the phase difference is 10μrad,and the relative measurement uncertainty of impedance in typical frequency and range is better than 3×10-5(k=3).
作者
谷静
杨雁
陆青
滕召胜
Gu Jing;Yang Yan;Lu Qing;Teng Zhaosheng(College of Electrical and Information Engineering,Hunan University,Changsha 410082,China;National Institute of Metrology,China,Beijing 100029,China)
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2020年第7期29-37,共9页
Chinese Journal of Scientific Instrument
基金
国家重点研发专项(2019YFF0216800)
国家自然科学基金(51877202)项目资助
关键词
计量学
交流电桥
阻抗测量
电桥平衡
模拟开关
metrology
AC bridge
impedance measurement
bridge balance
analog switch
