基于微液滴介质和差分电容器的静电式微型振动发电机

Micro electrostatic seismic power generator based on droplet and differential capacitors

针对现有悬臂梁式微型振动发电机存在低频响应不敏感,抗冲击能力差等问题,提出了一种利用微液滴介质拾振实现差分电容器变化及电荷转移的静电式微型振动发电机新结构。根据驻极体模型,推导出了差分电容器极板的电荷分布公式;结合微液滴作受迫正弦振动假设,建立了静电式微型振动发电机的数学模型。采用COMSOL Multiphysics软件对微液滴运动及电容器极板电荷分布进行了仿真,得到了发电机的输出电压幅频特性。制作出了以汞为介质的静电式微型振动发电机样机,进行了样机的性能测试。实验结果表明:该静电式微型振动发电机共振频率为3Hz,在加速度为3 g、振动激励频率为3Hz,负载为1MΩ时,测得样机输出电压峰-峰值为1.21V,输出功率为0.73μW,实现了环境中低频振动能量的获取与转换。

A micro electrostatic seismic power generator based on a droplet was proposed for harvesting the seismic energy in low frequency to improve its low frequency response and impact resistance abilities.The generator structure was based on the charge transfer between the differential capacitors inducted by the movement of the micro droplet in the electric field of an electret.According to the electret model,the charge distribution on the differential capacitors was derived.Combined with the assumption of forced sinusoidal vibration of the micro droplet,a mathematic model of the micro power generator was established.The COMSOL Multiphysics was employed to simulate the micro droplet movement and charge distribution,then the voltage-frequency characteristics were obtained.A prototype of the electret and micro-droplet-based micro seismic power generator was developed and tested.Its resonant-frequency is 3 Hz,the output power is about 0.73 μW on 1 MΩ resistance when the vibration acceleration is 3 g under a resonant frequency.It can scavenge the energies from low-frequency external vibrations.