高分辨率连续可调的直流电流比例变换装置

Continuous adjustable direct current ratio conversion device characterized by high resolution

基于测差原理的直流电流比例量值溯源通常是满足测量不确定度要求的有效途径。然而,电流比例可调分辨率的短板限制了实际溯源的应用范围。提出“等效分数匝”的概念,建立比例深度调节的数学模型,突破现有理论下比例最小步进值的束缚,实现多盘联动、分辨率达到1×10、误差优于±2×10的直流电流比例变换装置。级联两台电流比例标准器,调节组合后的比例与被校比例名义值一致,解决量程内全步进值溯源的难题。针对该变换装置,提出一种基于参考绕组的自校准方法,逐盘测量一次绕组与参考绕组和二次绕组的差值,关联各盘间误差,得到任意盘任意置位下的比例实际值,具备不依赖上一级标准器、实时复现量值的特点。

The traceability of direct current ratio based on the principle of difference measurement is usually an effective way to meet the requirement of measurement uncertainty. However, the shortboard with the ratio adjustable resolution limits the application range of practical traceability. In this article, we propose the concept of equivalent fractional turns, establish the mathematical model of deep adjustment, break through the bondage of the ratio minimum step value under the existing theory, and realize the direct current ratio conversion device with the characteristics of multi-disk linkage with the resolution 1×10and the error superior to ±2×10. The nominal ratio value of two standard devices is adjusted after linkage to be consistent with the calibrated one and solve the problem of full step value traceability within the range. A self-calibration method based on the reference winding is proposed for this conversion device. The difference value among the primary winding, reference winding, and secondary winding is measured in proper order. We correlate the error between the disks and obtain the actual ratio value of any disk at any position, which is characterized by real-time reproduction without relying on the upper standard device.