磁性反转双稳态微机械电磁振动能量采集机理及其应用

Vibration energy harvesting is the key technology to meet the power requirement of the wireless sensor network and implantable devices. Currently the bottleneck for the application of these devices are the too narrow bandwidth and the limited output power. This project proposed to solve these problems by the combination of the magnetic circuit optimization and non-linear resonance. On the one hand, the device was set to operate at the bi-stable state, which may broaden the working bandwidth and increase the output power significantly. On the other hand, the direction of the magnetic flux was set to be reversed during the transfer between the two stable state. In this way, not only the value , but also the polarity of the magnetic gradient was changed. As a result, the output power of the bistable energy transfer process could be increased substantially to overcome the performance bottleneck of current devices. In order to realize this principle, the electromechanical coupling factors related to the process should be analyzed carefully. The critia to realize the high energy orbit in the magnetic bistablility as well as the magnetic polarity reversement should be clarified. It will offer a guideline for the device design according to the principle. In order to varify the feasibility of the principle, the prototype device will be made with the batch-fabrication technology and the performance will be measured. This project explores the possible means to enhance the mechanical-electrical energy transfer effeciency, the obtained result may be a key technology for the power solution of the wireless sensor network in the future.

振动能量采集是满足未来无线传感网与植入式器件供能的关键技术，工作频宽过窄和输出功率过低是其实用化亟待解决的瓶颈问题。本项目提出将双稳态振动与磁性反转相结合的解决思路：一方面使器件工作在周期性井间振动双稳态，从而明显提升器件内部的振动能量传递效率，另一方面，使得双稳态切换过程中感应绕组中的磁通量，不仅大小发生变化，更改变其方向，进一步显著提高上述双稳态切换过程的能量转换效率，从而实现机电能量转换全过程综合优化。为此分析微型化器件中上述机-磁-电耦合机理，阐明调整磁性反转磁路中周期性井间振动双稳态所必须遵循的优化原则，为器件设计提供理论依据，并采用集成制造方法研制微型化原理样机，测试并分析器件性能，以验证上述原理的可行性。本项目是微米尺度上，通过调整交变磁场与非线性振动的相互作用，优化机电能量传递/转换过程的有益探索,研究成果也将为解决无线传感网等相关领域的供能问题提供关键技术。

振动能量采集是满足未来无线传感网与植入式器件供能的关键技术，工作频宽过窄和输出能量不足是其亟待解决的瓶颈问题。为此本项目提出将磁性反转与双稳态谐振相结合的解决思路总结上述研究工作，本项目的研究内容及成果主要包括以下几个方面：.1）提出了描述能量采集器件动态特性的结构动力学响应模型，据此可以分析器件结构形状、尺寸参数对于静态力学特性和动态非线性谐振特性的影响规律。.2）建立了器件静态力学特性、动态非线性谐振响应特性、以及输出电压-频谱特性的自动测试系统。其静态力分辨率可达纳牛量级 ，行程分辨率可达纳米量级。并自动分析记录不同振动频率作用下，能量采集器的响应振幅与输出电压，为在不同能量域评估所提出模型的正确性与有效性提供了试验平台。.3）验证了通过极性反转与磁路优化提高器件能量转换效率的可行性。理论分析与试验结果表明，在相同输入振动的作用下，极性反转前后器件的输出电压可以提高约一个数量级。相同输入振动作用下，磁路闭合与开路相比，输出电压能够增大约1倍。通过优化磁路结构，可以进一步将输出电压提升1个数量级。.4）在基于上述模型对器件结构形状、尺寸参数优化的基础上，提出了器件原理结构方案，试验结果表明，经过优化，器件的工作带宽可达120Hz。输出电压可达100mV以上，体积可缩小至0.2立法厘米以下。.上述成果的科学意义在于，提出并验证了一种有效提升振动能量采集器工作带宽和能量转换效率的可行方法，同时建立起非线性条件下评估结构形状、尺寸参数对微结构静力学、动力学响应特性影响规律的分析模型及实验观测平台，为理论分析优化和试验验证提供了分析工具与评估手段。同时揭示了磁路优化对于提升振动能量采集器转换效率的巨大潜力，在工程实践中，可以根据上述模型有的放矢的调整器件结构形状、尺寸参数，满足不同环境振动频率及工作带宽的要求。