A structure consisting of a spiral piezoelectric transducer and a concentrated mass is proposed as a low-frequency piezoelectric power harvester. A theoretical model is developed for the system from the theory of piez...A structure consisting of a spiral piezoelectric transducer and a concentrated mass is proposed as a low-frequency piezoelectric power harvester. A theoretical model is developed for the system from the theory of piezoelectricity. An analysis is performed to demonstrate the low-frequency nature of the system. Other basic characteristics of the power harvester including the output power, voltage, and efficiency are also calculated and examined.展开更多
The nonlinear behaviors of a circular-cylinder piezoelectric power harvester （CCPPH） near resonance are analyzed based on the flow-induced flexural vibration mode. The geometrically-nonlinear effect of the cylinder ...The nonlinear behaviors of a circular-cylinder piezoelectric power harvester （CCPPH） near resonance are analyzed based on the flow-induced flexural vibration mode. The geometrically-nonlinear effect of the cylinder is studied with considering the in-plane extension incidental to the large defection. The boundary electric charges generated from two deformation modes, flexure and in-plane extension, were distinguished with each other because the charge corresponding to the latter mode produces no contribution to the output current. Numerical results on output powers show that there are multi- valuedness and jump behaviors.展开更多
Torsional vibration of a circular piezoelectric shell of polarized ceramics mounted on a rotationally vibrating base is analyzed. The shell is properly electroded and connected to a circuit such that an electric outpu...Torsional vibration of a circular piezoelectric shell of polarized ceramics mounted on a rotationally vibrating base is analyzed. The shell is properly electroded and connected to a circuit such that an electric output is generated. The structure analyzed represents a piezoelectric generator for converting mechanical energy from angular vibrations to electrical energy. Analytical expressions and numerical results for the output voltage, current, power, efficiency and power density are given.展开更多
Low-temperature thermal energy conversions down to exergy zero to electric power must contribute energy sustainability. That is to say, reinforcements of power harvesting technologies from extremely low temperatures l...Low-temperature thermal energy conversions down to exergy zero to electric power must contribute energy sustainability. That is to say, reinforcements of power harvesting technologies from extremely low temperatures less than 373 K might be at least one of minimum roles for the current generations. Then, piezoelectric power harvesting process for recovering low-temperature heats was invented by using a unique biphasic operating medium of an underlying water-insoluble/low-boiling-point medium (i.e. NOVEC manufactured by 3M Japan Ltd.) in small quantity and upper-layered water in large quantity. The higher piezoelectric power harvesting densities were naturally revealed with an increase in heating temperatures. Excessive cooling of the operating medium deteriorated the power harvesting efficiency. The denser operating medium was surpassingly helpful to the higher piezoelectric power harvesting density. Concretely, only about 5% density increase of main operating medium (i.e. water with dissolving alum at 0.10 mol/dm3) came to the champion piezoelectric power harvesting density of 92.6 pW/dm2 in this study, which was about 1.4 times compared to that with the original biphasic medium of pure water together with a small quantity of NOVEC.展开更多
在单一效应的MEMS振动驱动微能源的基础上,提出了一种MEMS压电-磁电复合振动驱动微能源器件。该微能源由八悬臂梁-中心质量块结构和永磁铁两部分组成,环境振动使中心质量块振动,PZT压电敏感单元由于压电效应产生电势差;同时中心质量块...在单一效应的MEMS振动驱动微能源的基础上,提出了一种MEMS压电-磁电复合振动驱动微能源器件。该微能源由八悬臂梁-中心质量块结构和永磁铁两部分组成,环境振动使中心质量块振动,PZT压电敏感单元由于压电效应产生电势差;同时中心质量块上集成的高密度线圈切割磁感线产生感应电动势,将压电转换与磁电转换相结合把振动能转换为电能。建立了该结构的数学模型并用有限分析软件Ansys12.0对该器件进行力学特性分析,最后对加工出的微能源进行性能测试。测试结果表明,该微能源谐振频率为8 Hz,易与环境发生共振;在共振条件下,施加1 gn的加速度,器件压电发电开路输出电压峰峰值达154 m V,磁电发电开路输出电压峰-峰值达8 m V,有望为无线传感网络节点提供稳定的能源。展开更多
基金supported by the National Natural Science Foundation of China(Nos.10932004 and 11272127)
文摘A structure consisting of a spiral piezoelectric transducer and a concentrated mass is proposed as a low-frequency piezoelectric power harvester. A theoretical model is developed for the system from the theory of piezoelectricity. An analysis is performed to demonstrate the low-frequency nature of the system. Other basic characteristics of the power harvester including the output power, voltage, and efficiency are also calculated and examined.
基金supported by the National Natural Science Foundation of China(Nos.10932004 and11272127)a grant from the Impact and Safety of Coastal Engineering Initiative,a Center of Excellence Program of Zhejiang Provincial Government at Ningbo University(No.zj1213)
文摘The nonlinear behaviors of a circular-cylinder piezoelectric power harvester （CCPPH） near resonance are analyzed based on the flow-induced flexural vibration mode. The geometrically-nonlinear effect of the cylinder is studied with considering the in-plane extension incidental to the large defection. The boundary electric charges generated from two deformation modes, flexure and in-plane extension, were distinguished with each other because the charge corresponding to the latter mode produces no contribution to the output current. Numerical results on output powers show that there are multi- valuedness and jump behaviors.
文摘Torsional vibration of a circular piezoelectric shell of polarized ceramics mounted on a rotationally vibrating base is analyzed. The shell is properly electroded and connected to a circuit such that an electric output is generated. The structure analyzed represents a piezoelectric generator for converting mechanical energy from angular vibrations to electrical energy. Analytical expressions and numerical results for the output voltage, current, power, efficiency and power density are given.
文摘Low-temperature thermal energy conversions down to exergy zero to electric power must contribute energy sustainability. That is to say, reinforcements of power harvesting technologies from extremely low temperatures less than 373 K might be at least one of minimum roles for the current generations. Then, piezoelectric power harvesting process for recovering low-temperature heats was invented by using a unique biphasic operating medium of an underlying water-insoluble/low-boiling-point medium (i.e. NOVEC manufactured by 3M Japan Ltd.) in small quantity and upper-layered water in large quantity. The higher piezoelectric power harvesting densities were naturally revealed with an increase in heating temperatures. Excessive cooling of the operating medium deteriorated the power harvesting efficiency. The denser operating medium was surpassingly helpful to the higher piezoelectric power harvesting density. Concretely, only about 5% density increase of main operating medium (i.e. water with dissolving alum at 0.10 mol/dm3) came to the champion piezoelectric power harvesting density of 92.6 pW/dm2 in this study, which was about 1.4 times compared to that with the original biphasic medium of pure water together with a small quantity of NOVEC.
文摘在单一效应的MEMS振动驱动微能源的基础上,提出了一种MEMS压电-磁电复合振动驱动微能源器件。该微能源由八悬臂梁-中心质量块结构和永磁铁两部分组成,环境振动使中心质量块振动,PZT压电敏感单元由于压电效应产生电势差;同时中心质量块上集成的高密度线圈切割磁感线产生感应电动势,将压电转换与磁电转换相结合把振动能转换为电能。建立了该结构的数学模型并用有限分析软件Ansys12.0对该器件进行力学特性分析,最后对加工出的微能源进行性能测试。测试结果表明,该微能源谐振频率为8 Hz,易与环境发生共振;在共振条件下,施加1 gn的加速度,器件压电发电开路输出电压峰峰值达154 m V,磁电发电开路输出电压峰-峰值达8 m V,有望为无线传感网络节点提供稳定的能源。
