低频环境下碰撞式压电振动能采集器

Collisional Piezoelectric Vibration Energy Harvesters in Low Frequency Environments

现实中由于环境振动频带较窄使得能源采集器在低频时效率较低,为此课题组设计了一种可以在低频环境下表现优异的压电能量采集器,并拓宽了其收集频带。采用碰撞方法将采集器进行升频以适应低频环境,采用齿条齿轮传动带动拨片撞击悬臂梁实现动能采集;结合前人的研究完善了欧拉-伯努利梁振动方程,给出在振动过程中悬臂梁的精准位置和振型方程;简化传动模型给出拨片轴的近似运动方程并根据动量定理计算出碰撞前后各部件速度;综合建立整个系统的动力学方程并通过机电耦合方程建立了系统的电学方程。实验验证表明:所设计的采集器比之常规悬臂梁采集器采集频带扩宽了11.23%,输出电压提高了38.2%。所设计的采集器输出电压在低频时可以实现频繁阶跃,大大改进了压电振动能采集器在低频环境下的采集性能,使其更适宜低频环境下的能量采集。

In view of the low efficiency of the energy harvester at low frequencies due to the narrow ambient vibration band,a piezoelectric energy harvester that performs well in low frequency environments was designed,and its harvesting band was broadened.The collision method was adopted to design the energy harvester with frequency-up conversion to adapt to the low frequency environments.A rack and gear drive was used to drive the paddles against a cantilever beam to achieve kinetic energy harvesting.The Euler-Bernoulli beam theory was improved by combing the previous research,and the precise position and vibration equation of the cantilever beam during the vibration process were presented.The approximate equations of motion of the paddle shaft was obtained by simplifying the transmission model,and the velocities of the components before and after the collision according to the momentum theorem were calculated.The kinetic equations of the whole system were set up and the electrical equations of the system were established through the electromechanical coupling equations.The experimental validation shows that the designed harvester broadens the bandwidth by 11.23%and increases the output voltage by 38.2%compared with the conventional cantilever beam harvester.The output voltage of the designed harvester can be stepped frequently at low frequencies,which greatly improves the harvesting performance of the piezoelectric vibration energy harvester in low frequency environments and makes it more suitable for energy harvesting in low frequency environments.