微型之字形压电式能量收集器输出电压的建模和仿真

为了有效解决无线传感器网络节点的供电难题,提出之字形结构的微型压电式能量收集器。相比于传统的直悬臂梁,此结构等效加大了压电梁的长度,降低了系统的固有振动频率。建立了之字形压电梁的本构方程和受迫振动方程,推导得到其输出电压的频域表达式。基于之字形压电梁的结构,利用ANSYS软件对其进行了谐响应分析。仿真结果表明,压电梁的输出电压在各阶固有振动频率处存在极值,符合理论分析的结果；输出电压大小随压电梁长度增加而降低,随压电梁宽度增加而升高,但均为非线性关系；压电梁末端质量块的长度和厚度、基体层厚度减小时,会导致输出电压的增大。在论文中所提出的结构尺寸下,10根直梁构成的之字形结构压电梁,在其一阶固有振动频率处,输出电压可达10 V以上,符合无线传感器网络节点的实际供电需求,证明了之字形压电梁结构的有效性。

Modeling and simulating of micro zigzag piezoelectric energy harvester

In order to effectively solve the power problem of wireless sensor network node,zigzag microstructure for piezoelectric energy harvester is proposed. Compared to the traditional straight cantilever,this structure is equivalent to increase the length of the piezoelectric beam,reduces the natural vibration frequency of the system. To establish the constitutive equations and forced vibration equations of zigzag piezoelectric cantilever,the output voltage expres-sion is derived. Based on structure of zigzag cantilever,the harmonic response analysis is simulated by ANSYS soft-ware. Simulation results show that the output voltage is present extremes in the order natural vibration frequencies,it is in accord with the results of theoretical analysis;the output voltage amplitude increases when piezoelectric beam length decreases,with the increase of the piezoelectric beam width,the output voltage increases,that is non-linear relationship;when the length and thickness of quality block,the base layer thickness decrease,the output voltage will increase. Based on the structure size proposed in the paper, the zigzag cantilever composed of 10 straight beams,in the first-order natural vibration frequencies,the output voltage is up to 10 V,it meets the actual power re-quirements of wireless sensor network nodes,proves the validity of the zigzag piezoelectric cantilever structure.