MEMS压电阵列振动能量收集器

摘要

In recent years,a great effort has been devoted to the study of micro piezoelectric vibration energy har-vester(VEH)with the development of Power MEMS.However,the output voltage of conventional d31 VEH based on a PZT film is generally low,which is difficult for application.In order to raise the output voltage of the MEMS piezoe-lectric vibration energy harvester,this paper presents a MEMS piezoelectric cantilever array structure which can raise the voltage by connecting the piezoelectric elements in series.By using the finite element method for structural simulation analysis and optimization,the optimized piezoelectric cantilever dimensions is 3 mm×2.4 mm×0.05 mm and silicon mass dimensions is 8 mm×12.4 mm×0.5 mm.The principle prototype was fabricated by MEMS fabrica-tion process.The device produces a maximum open circuit output voltage of 9.16 Vrms and a maximum output power of 151.8 μW with 5.51 Vrms output voltage with an optimal resistive load of 200 kΩ from 1 gn acceleration at its resonant frequency of 237.9 Hz.%近年来，随着微能源的发展，微型压电振动能量收集器得到了广泛关注，但传统d31模式PZT薄膜微型压电振动能量收集器输出电压普遍较低，难以满足应用需求。为提高微型压电振动能量收集器的输出电压，论文提出了共质量块悬臂梁阵列压电振动能量收集器新结构，该结构包含压电悬臂梁单元组成的阵列和一个质量块，悬臂梁阵列共用质量块。采用有限元方法对该结构进行了优化设计，得到压电悬臂梁单元优化尺寸为3 mm×2.4 mm×0.05 mm，硅质量块优化尺寸为8 mm×12.4 mm×0.5 mm。设计了MEMS压电阵列振动能量收集器加工工艺流程，加工出原理样件。在1 gn 加速度，239.7 Hz谐振频率激励下，测试得到样件输出开路电压有效值为9.16 V；在最优化负载200 kΩ下，负载输出电压有效值为5.51 V，输出功率为151�8μW。