A broadband piezoelectric vibration energy harvesting system based on sensorless direct resonance tuning technique

Abstract

This letter proposes a broadband piezoelectric energy harvesting (PEH) system based on sensorless direct resonance tuning (SDRT) technique. The PEH system consists of a frequency-tunable harvester, an energy harvesting (EH) subsystem and a control subsystem. The EH subsystem can transfer energy from the harvester to the storage. The control subsystem can detect the ambient vibration frequency and adjust the inherent frequency of the harvester using a servo motor to match the ambient vibration. Furthermore, the vibration frequency detection is based on the harvester itself rather than an additional sensor. Finally, the experimental results show that the prototyped PEH system can adjust its inherent frequency to achieve resonance in the range of 36–50 Hz. In addition, the EH performance achieved by the proposed SDRT technique can reach at least 77.6% of the manual frequency tuning method.