谐振式压电叠堆的高效换能结构研究

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压电叠堆具有纵向机电耦合系数高、耐疲劳性强的特点，但在低频振动条件下，压电叠堆的机电转换效率低，从而限制了其在结构振动能量收集方面的应用。通过将谐振频率接近结构振动频率的谐振器附加在压电叠堆表面形成谐振式压电换能系统，可以有效提高谐振频率附近的机电能量转换效率。对谐振式压电换能结构进行参数建模，以压电叠堆所受纵向力与结构激励力的比值衡量谐振式压电叠堆的换能效率，确定系统有效换能频带的宽度与系统的结构设计参数的关系，从而给出谐振式压电换能系统参数优化设计方法。谐振式压电换能结构的实验表明谐振器能有效增加较低振动频率下的机电能量转换效率，提高输出的开路电压。 Piezoelectric stack has the advantages of high longitudinal electro-mechanical coupling coefficient and strong fatigue-resistance, but its electro-mechanical conversion efficiency is not high under lower frequency vibration, it limits its applications in vibration energy gathering. A novel oscillator piezoelectric energy conversion system （OPECS） was presented to enhance its conversion efficiency nearby resonant frequency through attaching an oscillator onto the surface of the piezoelectric stack. The parametric model of an OPECS was built at first. According to the model, its electro-mechanical conversion efficiency was evaluated using a ratio of the longitudinal force of the stack to the exciting force. Then the relationship between the effective conversion bandwidth and the structural parameters were determined, thus the optimal design principles of the structural parameters were obtained. Experimental results showed that OPESC can effectively increase the electro-mechanical conversion efficiency in lower frequency vibration and raise the output voltage of the piezoelectric stack.