基于自偏置巨磁电效应的采能和传感一体化微型自供电无线磁传感器研究

Wireless Sensor Networks (WSN) is the core of the Internet of Things (IOT). However, the function cycle of WSN is restricted by battery life. The power supply bottlenecks of WSN could be solved by the self-powering sensor completely, which performs both energy harvesting and information acquisition functions. The self-powering sensor is used increasingly wilder in our life and is the inevitable trend of the sensor technology development, resulting from it does not require external power source or battery maintenance. However, the current self-powering sensor techniques mainly focus on the two functions independently. Moreover, the relation especially the interaction of the two functions are less studied. In this project, we propose a novel hybrid self-powering magnetic sensor integrated energy harvesting and sensing functions simultaneously. This self-powering sensor with both energy harvesting and sensing functions in one structure, which could improve the efficiency of energy use, optimally design the self-powering sensor and simplify manufacturing technology. The study of giant self-biased magnetoelectric response material is the breakthrough point of this project. We should systematic research the magnetic field sensing technologies and the multiple energy resource harvesting technologies which both based on the giant self-biased magnetoelectric response. Explore the physical mechanisms which the two functions of energy harvesting and sensing can be achieved simultaneously. Provide a theoretic design method of the achievement of the structure integrated self-powering magnetic sensor with two functions of energy harvesting and sensing. Provide a theoretic basis and technical support for the power supply of wireless sensors in IOT.

无线传感器网络是物联网的核心。电池寿命限制了现有无线传感器网络的功能周期。自供电传感器同时具有能量采集和信息获取功能，不需要外接电源或电池维护，可不受限制地持久应用于各种场合，能够根本解决无线传感器网络的供电瓶颈，是传感技术发展的必然趋势。但是，目前自供电传感技术几乎都是对这两种功能部件进行独立研究，而对二者之间的联系，尤其是可能产生的相互作用鲜有报道。本项目创新提出"采能和传感一体化结构"的自供电磁传感器，在一种结构中同时实现采能和传感两种功能，在激励能量作用下直接产生传感信号，提高能量使用效率，优化自供电传感器设计并简化加工工艺。以自偏置巨磁电复合材料研究为切入点，系统研究基于"自偏置巨磁电效应"的磁传感原理和多源能量采集技术，探索能同时实现采能和传感功能的物理机制，提出一套实现采能和传感一体化结构的自供电无线磁传感器设计方法，为解决我国物联网中无线传感器的电源供给提供理论和技术支撑。

无线传感器网络是物联网的核心。电池寿命限制了现有无线传感器网络的功能周期。自供电传感器同时具有能量采集和信息获取功能，不需要外接电源或电池维护，可不受限制地持久应用于各种场合，能够根本解决无线传感器网络的供电瓶颈，是传感技术发展的必然趋势。本项目创新提出采能和传感一体化结构的自供电磁传感器，在一种结构中同时实现采能和传感功能，优化设计并简化工艺，为解决我国物联网中无线传感器的电源供给提供理论和技术支撑。本项目研究自偏置巨磁电效应机理和自偏置磁电复合材料的制备工艺及表征；研究基于自偏置巨磁电效应的磁传感机理和自偏置磁传感器的设计优化及性能测试；研究多源能量采集器及其宽频化；研究敏感信号分离原理和自供电磁传感器的一体化结构设计及性能测试；研究基于一体化自供电磁传感器的输电线电流检测等。重要研究结果包括：(1)针对FeCoV/Terfenol-D/PZT（F/M/P）磁电复合材料，建立了自偏置磁电响应理论模型，确定了最佳制备工艺参数，当FeCoV厚度为90微米时，样品的零偏置磁电电场系数可达19.6 V/cmOe。(2)建立了自偏置磁传感器静动态响应模型，研究了影响传感特性的主要因素，通过仿真模拟对传感器敏感单元进行了优化设计；通过实物加工测试，传感器性能优良，灵敏度达到1947mV/Oe，线性度为0.348%，最小分辨率为2.43×10-8 T。(3)研究了基于非线性拓扑结构的宽频振动能量采集器，建立了非线性振动模型，可明显拓宽频带；设计了一体化结构的多源能量采集器，在负载为2 MΩ、磁场强度为3 Oe、振动加速度为1 g时，最大输出功率达到214 μW。(4)研究了自供电磁传感器机理并明确了敏感信号的分离原理，设计并加工出样机，可有效采集环境能量并通过电源管理电路进行存储，再对无线通信模块供电，以实现磁敏感信号在30 m范围内数据的可靠传送。成功将自供电磁传感器应用到输电线的电流检测中，灵敏度达到1.304 mV/A。一体化自供电磁传感器可显著提高能量使用效率，极大拓宽无线传感器网络的应用领域，使其需求产生“井喷效应”。