基于磁致伸缩效应的声表面波电流传感器响应机理及结构优化研究

There are extremely urgent needs for current sensor with properties of excellent sensitivity, high-precision, superior stability, and good stability and reliability in a variety of modern industrial fields such as Smart grid line testing, metallurgical and power supply rail transit safety warning and rescue, power relay protecting in industrial automation. To overcome the outstanding problems of the traditional current detection technology in resistance, insulation and cost, a new surface acoustic wave (SAW) current sensor based on magnetostrictive effect is studied in this proposal, which include a combination of magnetostrictive film (TbDyFe) with high magnetic sensitivity and SAW technology with fast response, hence, fast response, high sensitivity, excellent stability and reliability, and passive and passive measurement towards current were expected to be realized. So, the performed SAW sensor exhibits significant application prospect and academic value in above fields. The purpose of this project is breaking through some key technologies as response mechanism, and optimal design on functional structure of the sensor by combing the SAW theory and principles of magnetism. The main contents in this proposal include: (1) analysis on temperature properties of SAW device coated with temperature-compensated SiO2 thin layer; (1) Theory analysis on the response mechanism of the SAW current sensor utilizing magnetostrictive effect; (3) Optimization on functional structure and preparation technology, (4) performance evaluation of the SAW current sensor. This project exhibits great significance of the practical application of current sensor based on surface acoustic wave technology.

具有高灵敏度、高分辨率、良好稳定性与可靠性的电流在线检测技术在智能电网、电力冶金与轨道交通中供电安全预警与救援、工业自动化中电源继电保护等领域有着迫切需求。针对传统电流传感技术在抗干扰性、绝缘性以及成本等方面所面临的突出问题，本项目研究了一种基于磁致伸缩效应的新型声表面波电流传感技术，将磁致伸缩（TbDyFe）薄膜的高磁敏性与声表面波的快速响应特点相结合，可实现快速、高灵敏、稳定可靠及无线无源的电流检测，在上述领域极具工程应用前景和学术价值。本项目旨在基于声表面波传感器理论与磁力学原理，通过对传感机理及功能结构优化等的研究，突破其中的关键技术。主要研究内容有：（1）采用SiO2温度补偿层的传感器件温度特性分析；（2）基于磁致伸缩效应的SAW电流传感器响应机理分析；（3）传感器功能结构优化、磁致伸缩薄膜制备技术；（4）传感性能评价。本项目研究对于促进声表面波电流传感器的实际应用具有重要意义。

具有高灵敏度、高分辨率与良好稳定性与可靠性的电流在线检测技术在智能电网线路检测、电力冶金与轨道交通中供电安全预警与救援、工业自动化中电源继电保护等领域具有重大应用价值。本项目将声表面波传感技术的快速响应特点与磁致伸缩薄膜的高磁敏特点相结合，从声表面波电流响应机理的理论分析、传感器功能结构的优化以及传感实验等方面开展研究，实现了一种具有高灵敏度、快速响应的SAW电流传感器。.首先，基于分层介质中声波传播理论与磁力学原理，研究了沉积SiO2薄层的128°YX-LiNbO3压电材料上SAW的传播特性，特别分析了延迟温度系数与机电耦合系数随SiO2厚度的变化关系，提取出趋于零温度系数且机电耦合系数较大的薄层厚度。随后基于磁致伸缩敏感膜的磁致伸缩应变和ΔE效应，结合力学与电学边界条件以及磁力学原理，获取磁致伸缩薄膜/SiO2/压电晶体结构中磁场变化与声传播特性（传播速度）之间的关联特性，特别分析磁致伸缩薄膜膜厚对传感器响应的影响，从而确定出优化的传感结构设计参数。.在理论分析基础上，接下来对SAW电流传感器的功能结构进行了优化设计。研究了磁致伸缩薄膜的制备技术以及创新性地提出对磁致伸缩薄膜进行图形化设计使其充分释放磁致伸缩效应。利用COM理论及等效电路模型，仿真设计并制备出采用单向单相换能器（SPUDT）的低损耗高相位线性度的延迟性传感器件和高信噪比、低时域噪声及均一时域响应的反射延迟线传感器件。最后开展以FeGa和TbDyFe材料为磁敏膜的实验以对传感器性能进行评价。最终实验获得的基于点状FeGa薄膜的SAW电流传感器灵敏度高达37.9kHz/A，磁滞误差为0.81%，具有优异的可靠性和长期稳定性，优于已有的传感器原型，并对无线无源SAW电流传感器展开了积极的探索。