Design, analysis, and experimental studies of a novel PVDF-based piezoelectric energy harvester with beating mechanisms

Wireless sensor networks become increasingly important for structural health monitoring and other related applications. Consequently, energy harvesters to convert environment wasted vibration energy into electricity for powering those sensor nodes become essential device have been realized by using MEMS technology. To achieve optimal performance, energy harvester must be operated at resonance state. However, the vibration frequencies of environmental vibrations are usually much less than that of those harvesters and this fact could be a major barrier for optimizing harvesting performance. In this paper, a new piezoelectric energy scavenging concept is proposed and demonstrated to convert environmental vibrations into electricity. Unlike previous MEMS-based piezoelectric harvesters, which suffer from frequency matching between environmental vibration and the system natural frequency, this work proposes a novel beating design using polymer piezoelectric materials in collaborating with a beating mechanism. I.e., by creating impact force via the low frequency vibration provided by the mechanism, it is possible to excite system natural frequency by the environmental vibrations and to operate the system at the resonance state. By experimental characterization, the overall harvesting efficiency of the proposed design is much greater than that from the conventional design. It shows that the proposed design could potentially improve the future design for piezoelectric energy harvesters significantly. In short, this primary study shows a promising scheme for guiding future development of high efficient piezoelectric harvesters.