Nonlinearities influences on performances of a strongly-coupled piezoelectric generator for broadband vibration energy harvesting

This paper reports the experimental bandwidth enhancement of a PMN-PT-based strongly-coupled piezoelectric generator exhibiting softening nonlinearities associated to a tunable electrical load. The frequency bandwidth of the harvester associated to a R-tuning technique increases from 3.5% to 12.3% as the acceleration level increases, while it increases from 10.1% to 12.3% with a RC-tuning technique. Then, we show that the exploitation of nonlinearities highly increases the harvesting bandwidth with R-tuning techniques, competing with RC-tuning ones at high-acceleration levels.