直管谐振式低频压电声能量回收系统

为了高效回收环境中的声能，基于阵列式压电换能器、直管谐振腔以及能量回收电路提出了一种声能量回收系统.当声波进入直管谐振腔，管中产生谐振驻波作用于压电换能器，将声能转换为电能.本文设计了能量回收电路并且进行理论、仿真分析实验研究了压电振子数量、声波频率、声压级对输出电压的影响，分析了负载电阻对输出电压及功率的影响.实验结果表明，该装置可回收不同频率的声能量，在声波频率为96Hz时发电效果最优.当入射声压级为110dB时，不使用能量回收电路，输出交流电压有效值最高达12.9V，输出交流功率最高达到799μW；使用设计的能量回收电路，最高输出直流电压为64.2V，最高输出直流功率为473μW.该声能量回收系统不仅可以作为声能量采集器，还能对无线传感节点等独立工作的微型电子系统供能.

Low Frequency Piezoelectric Acoustic Energy Harvest System with Straight Tube Resonance

In order to harvest the acoustic energy in the environment efficiently,an acoustic energy harvesting system is proposed with piezoelectric transducer array,straight tube resonator and energy harvesting circuit.When the acoustic wave transmits into the straight tube resonator,the resonance standing wave is generated in the tube,and excites the piezoelectric transducers;then the acoustic energy is converted into electrical energy.An energy harvesting circuit is designed and analyzed theoretically with simulation.The relationship between the number of piezoelectric chips,the frequency of acoustic waves,the acoustic pressure level and the output voltage is studied with experiments.The output voltage and power are analyzed with the change of load resistance.Experimental results show that the proposed system can harvest the acoustic energy in different frequencies,and the harvested power achieve the maximum at the sound frequency of 96Hz.Without using the energy harvesting circuit,the maximum output AC voltage effective value is 12.9V and the maximum output AC power is 799μW at the incident acoustic pressure level of 110dB.When the proposed energy harvesting circuit is applied,the maximum output DC voltage is 64.2V and the maximum output DC power is 473μW.The acoustic energy harvesting system can not only harvest acoustic energy,but also can power the micro electronic systems such as wireless sensor nodes.