多方向宽频磁电式振动能量采集器

Multi-directional and broadband vibration energy harvester using magnetoeletric transducer

针对目前振动能量采集器只能拾取环境振动中一个方向的能量，以及响应频带较窄的问题，提出并设计了一种由弹性圆柱悬臂梁、环形磁路和复合磁电换能器组成的多方向宽频带振动能量采集器。圆柱悬臂梁具有在其横截面内沿任意方向振动的特性，同时，借助磁力耦合，使任意方向振动具有非线性的特点，从而采集器实现多方向宽频带振动能量拾取。理论推导了磁力作用下圆柱悬臂梁的非线性动力学方程，以及电压输出模型；借助磁场分析软件AnsoftMaxwell分析了矩形、圆形和环形永磁铁分别组成3种磁路的磁场分布，研究了不同磁路中磁力、磁场强度及其变化量等因素对动力学方程和电压输出的影响，为获得更优性能的采集器提供了设计依据。实验结果表明：在5．88m／s。的加速度下，具有环形磁路的采集器能够拾取0°～180°多方向的振动能量，各个方向响应频带宽度达到4．4～5．6Hz；负载电阻为3MQ时，采集器输出0．5mW的最大功率。

Aiming at the problems that existing vibration energy harvesters can only pick up the energy in single di- rection and narrow bandwidth, a multi-directional and broadband vibration energy harvester using magnetoelectric transducer is proposed. The harvester consists of a cylinder elastic cantilever beam, a ring magnetic circuit and a com- plex magnetoelectric transducer. Owing to the magnetic coupling,the cylinder elastic cantilever beam exhibits a non- linear oscillation characteristic in arbitrary directions in the cross-section plane, as well as a wide bandwidth. The nonlinear dynamic equation and electrical-output model of the cylinder elastic cantilever beam are developed. The magnetic analysis software Ansoft Maxwell is used to analyze the magnetic field distributions of 3 magnetic circuits composed of rectangular, round and ring permanent magnets ; and the influences of the nonlinear magnetic force, mag- netic field intensity and their variations for different magnetic circuits on the nonlinear dynamic equation and electri- cal-output are analyzed, which provides the design basis for designing the vibration energy harvesters with better per- formances. The experimental results show that the harvester with ring magnetic circuit can pick up the vibration ener- gy at arbitrary angles from 0° to 180° with a bandwidth range from 4.4 Hz to 5.6 Hz under the acceleration of 5.88 m/s2, and has the maximum power of 0.5 mWacross an optimal resistance of 3 MΩ.