Yu Hao, Qian Zheng, Liu Huayi, Qu Jiaqi
School of Instrumentation Science and Opto-Electronics Engineering, Beihang University, Beijing 100191, China.
Sensors (Basel). 2018 Feb 14;18(2):578. doi: 10.3390/s18020578.
This paper analyzes the measurement error, caused by the position of the current-carrying conductor, of a circular array of magnetic sensors for current measurement. The circular array of magnetic sensors is an effective approach for AC or DC non-contact measurement, as it is low-cost, light-weight, has a large linear range, wide bandwidth, and low noise. Especially, it has been claimed that such structure has excellent reduction ability for errors caused by the position of the current-carrying conductor, crosstalk current interference, shape of the conduction cross-section, and the Earth's magnetic field. However, the positions of the current-carrying conductor-including un-centeredness and un-perpendicularity-have not been analyzed in detail until now. In this paper, for the purpose of having minimum measurement error, a theoretical analysis has been proposed based on vector inner and exterior product. In the presented mathematical model of relative error, the un-center offset distance, the un-perpendicular angle, the radius of the circle, and the number of magnetic sensors are expressed in one equation. The comparison of the relative error caused by the position of the current-carrying conductor between four and eight sensors is conducted. Tunnel magnetoresistance (TMR) sensors are used in the experimental prototype to verify the mathematical model. The analysis results can be the reference to design the details of the circular array of magnetic sensors for current measurement in practical situations.
本文分析了用于电流测量的圆形磁传感器阵列因载流导体位置而产生的测量误差。圆形磁传感器阵列是一种用于交流或直流非接触测量的有效方法，因为它成本低、重量轻、线性范围大、带宽宽且噪声低。特别是，据称这种结构对由载流导体位置、串扰电流干扰、传导横截面形状和地磁场引起的误差具有出色的抑制能力。然而，直到现在，载流导体的位置，包括未居中和平行度，尚未得到详细分析。在本文中，为了使测量误差最小，基于向量内积和外积提出了一种理论分析方法。在所给出的相对误差数学模型中，未中心偏移距离、未垂直角度、圆半径和磁传感器数量用一个方程表示。对四个和八个传感器之间因载流导体位置引起的相对误差进行了比较。实验原型中使用了隧道磁阻（TMR）传感器来验证该数学模型。分析结果可为实际情况下设计用于电流测量的圆形磁传感器阵列的细节提供参考。
