Research On Low-frequency And Wideband Piezoelectric Vibration Energy Harvesting Technology

Most low-power electronic devices are currently powered by conventional chemical batteries,but frequent battery replacement adds additional maintenance costs and is not easily implemented in certain environments.In this case,it is especially important to develop a system that can continuously power a miniaturized low-power device.Piezoelectric vibration energy harvester has become the object of international micro-energy research because of its many advantages such as easy integration and high energy density.Based on the research of cantilever beam piezoelectric vibration energy harvesting technology,a six-segment folded cantilever beam piezoelectric vibration energy harvester and a piezoelectric vibration energy harvester with elastic support can be designed to collect vibration energy efficiently under low frequency and wideband.The sixth-segment folded cantilever beam piezoelectric vibration energy harvester is composed of a folded six-segment cantilever beam,a proof mass and a piezoelectric plate.This design provides the harvester with a lower resonant frequency and a more compact resonant peak,which allows the harvester to have more available resonant modes,enabling efficient collection of vibrational energy in everyday vibration environments.At the same time,the folded cantilever beam extends the equivalent length of the entire beam,causing the structure to produce greater strain at the fixed end,which promotes a higher output voltage of the piezoelectric plate pasted near the fixed end.The piezoelectric vibration energy harvester with elastic support is composed of two elastic supports,a U-shaped bracket and a piece of piezoelectric plate,and the elastic support is composed of ordinary office rubber bands and mass blocks.By adjusting the elastic support,the equivalent stiffness coefficient of the entire structure can be reduced,eventually producing a new resonant peak in the lower frequency range and significantly reducing the resonant frequency of the cantilever beam.It is verified by experiments that the six-segment folded cantilever beam piezoelectric vibration energy harvester generates five resonance peaks in 0~30Hz,the effective working bandwidth is 11 Hz,the highest open-circuit output voltage is 20.78 V,and the optimal output power is 217.201?W.The characteristics of vibration energy are collected in multiple directions.Compared with the traditional cantilever beam energy harvester,the piezoelectric vibration energy harvester with elastic support reduces the resonant frequency of the whole structure from 16.5 Hz to 8.9 Hz,a total reduction of 46%;the resulting open circuit voltage peak is increased from 19.6V to 28.8V,an increase of 1.47 times.400k? and 250k? are the best matching loads of the piezoelectric vibration energy harvester with elastic support and the traditional cantilever beam energy harvester.The maximum output power is 1.416 m W and 0.740 m W respectively,and the power generation is increased by 87%.