针对线性、单一的振动能量俘能器存在工作频带狭窄、只能采集单向振动等问题,该文提出了一种适应货运列车等多向振动应用场景的新型多向振动俘能装置,以增强对环境中振动能量的俘获.该装置结合压电和电磁俘能器,通过螺旋圆柱弹簧和顶端质量有效捕获多向振动,并通过磁力传递振动能量至压电梁.合理设计了弹簧-质量结构,使其在较低的频率范围内可实现多种振动模态,拓宽了俘能器的谐振频带.为了充分利用压电材料,采用了变宽度压电悬臂梁,使应力均匀分布.压电梁自由端的永磁体随着压电梁的振动而产生变化的磁场,在线圈中产生感应电压.通过有限元分析和实验测试,验证了复合式俘能器可以采集多向振动能量,并测试了在z向振动激励下压电、电磁及复合式俘能器的最大输出功率.在频率 9.5 Hz、z 向振幅 2 mm 的正弦波激励下,复合式俘能器输出最大功率为 3.276 mW.该系统在理论上可为低功耗传感器提供持续电力,为机械能收集与能量转换领域提供技术支持.
Design and Experimental Study of a Multi-Directional Vibration Harvester
In response to the narrow working-frequency band and single-directional vibration capture of linear and single-mode vibration-energy harvesters,this paper proposes a novel multi-directional vibration-energy harvester that aims to enhance the capture of vibration energy in the environment.This device combines piezoelectric and elec-tromagnetic energy harvesters.It effectively captures multi-directional vibrations through a spiral cylindrical spring and top mass and transfers the vibration energy to a piezoelectric beam through magnetic force.The spring-mass structure is designed to support multiple vibration modes at a lower frequency range,broadening the resonance-fre-quency band of the energy harvester.To fully utilize the piezoelectric material,the device implements a variable-width piezoelectric cantilever beam,ensuring a uniform stress distribution.The permanent magnet at the free end of the piezoelectric beam generates a changing magnetic field in response to the beam vibration,inducing a voltage in the coil.Through finite-element analysis and experimental testing,the composite energy harvester was verified to capture multi-directional vibration energy.Moreover,the maximum output power of the piezoelectric,electromag-netic,and composite energy harvesters under z-directional vibration excitation was tested.The composite energy harvester yields an output power of 3.276 mW when subjected to a 9.5 Hz sine-wave excitation with a 2 mm z-axis amplitude.This system offers continuous power for low-power sensors,thus providing technological support for mechanical energy harvesting and energy conversion.
mechanical vibrationpiezoelectric-electromagnetic energy harvestingmagnetic couplingmulti-modal vibrationvariable-width cantilever beam
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