面向能量天平同步测量的磁链差测量方法研究

能量天平法作为一种质量量子基准研究方案,其中磁链差测量是能量天平测量过程的核心,其基本原理是对线圈感应电压的时间积分进行测量.原有的磁链差测量方法是基于数字积分原理的,当其应用于能量天平同步测量方法中时,难以克服数据采集卡的本征弱点,无法满足10-8量级的相对标准不确定度需求.为此,基于双积分型模数转换器(ADC)提出...

Research on the Flux Linkage Difference Measurement Method for Synchronous Measurement Based Joule Balance

The joule balance method is a quantized definition of the unit of mass research programme, in which the flux linkage difference measurement is a core part during the measurement process of joule balance, and its basic principle is the integral measurement of coil induced voltage over time. The joule balance is a method independently proposed in China to realize the quantized definition of the unit of mass. The flux linkage difference measurement is a core part during the measurement process of joule balance, whose basic principle is the integral measurement of coil induced voltage over time. When the original flux linkage difference measurement method based on the digital integration principle is applied to the synchronous measurement process of joule balance, it is difficult to overcome the intrinsic weakness of the data acquisition card so that it cannot achieve the 10^-8 magnitude of relative standard uncertainty. Therefore, a new method based on the dual-slope integration ADC is proposed to achieve the analog integral measurement. With the continuously analog integrating measurement characteristic of the dual-slope integration based ADC, the measurement error introduced by the level holding sampling process in the original method is eliminated. The measurement dead-zone introduced by ADC digital quantization is removed by the successive triggered measurement of multiple parallel ADCs. The measurement dispersion introduced by the accumulation of time-varying noise is suppressed by the time-shared noise zeroing of multiple ADCs. The test results show that after applying the above method in the synchronous measurement process, the relative standard uncertainty of flux linkage difference measurement is suppressed from 10^-6 to 1.7×10^-8.