压电俘能器结构及其力/电耦合作用分析

介绍了一种新的切实可行的能量俘获方法，即通过压电结构的力/电转换功能从环境振动中提取能量，实现微电子器件的无线供能。这种由压电结构制作的能从环境振动中提取能量的声波器件称为压电俘能器，可分为两类：一类是压电结构在环境振动激励下所输出的功率直接供给微电子器件工作，不进行能量储存，这类俘能器称为第一类压电俘能器（piezoelectric power harvester）；另一类是环境振动较弱，压电结构的输出功率低于器件的瞬时耗能，考虑到某些器件大部分时间处于休眠状态，而俘能器却随时可以从环境振动中提取能量，因此经过一段时间的能量累积后，由俘能器所储存的能量仍能满足器件的短期工作耗能。显然，这类俘能器需要具备能量储存功能，称为第二类压电俘能器（piezoelectric energy harvester）。本文详细介绍了压电俘能器结构以及两类俘能器的不同分析方法，阐述了提高俘能效率的有效措施并揭示了相关的改进机理，对压电俘能器的设计和应用具有重要意义。

ANALYSIS ON THE STRUCTURES OF PIEZOELECTRIC HARVESTERS AND THE CORRESPONDING ELECTROMECHANICAN COUPLINGS

A novel practical technology of energy-scavenging, through electromechanical conversion of piezoelectric structures to extract energy from ambient vibrations, is introduced for the realization of wireless energy supply to microelectronic devices. These acoustic-wave devices, consisting of piezoelectric structures for energy-scavenging, are called piezoelectric harvesters which can be divided into two categories: One is called piezoelectric power harvester whose ac output power scavenged from ambient vibrations is directly supply to electronic devices without any energy-storage; the second is called piezoelectric energy harvester which possesses energy-storage function. In some applications, a microelectronic device is required to perform its duty infrequently, for example a few minutes over a long period of time. The harvesters with energy-storage function can still supply those devices after a long energy accumulation, even if they operate in a low vibration background environment. The structures of piezoelectric power/energy harvesters and the analysis methods are described in detail in the paper. The effective measures to improve the efficiency of harvesters are illustrated and the corresponding mechanisms are revealed. There is some great significance on the design and application of piezoelectric power/energy harvesters.