Power Conversion Efficiency of Cantilever-Type Vibration Energy Harvesters Based on Piezoceramic Films

Piezoelectric energy harvesters are very attractive to supply devices for remote sensing applications; however, they suffer from some limitations related to their low-power generation. Recently, piezoceramic flexible patches with high power conversion efficiency have been made commercially available. These film transducers can be suitably used to realize compact low-cost vibration energy harvesters. In this article, the performance of a cantilever-type piezoceramic energy harvester (PCEH) has been thoroughly investigated. Different resonance configurations were obtained by varying the proof mass attached to the free end of the beam. The effects of the excitation features (amplitude and frequency) on generated power and energy conversion efficiency have been evaluated. Furthermore, a rectification and regulation circuit was connected downstream to the PCEH in order to achieve a dc output. In such configuration, the influences of the resonance frequency and the electrical load on the recharging and discharging times were also assessed.