Enhanced performance of piezoelectric energy harvester through three serial vibrators

This paper presents a piezoelectric harvester array with three identical energy harvesting vibrators (EHVs) arranged in series along the water flow direction. Each EHV consists of a piezoelectric beam and an interference cylinder. Three serial EHVs are placed upright in the water channel. Prototypes of three EHVs are fabricated and experiments are conducted to explore the vibration response and harvesting performance. The experimental results demonstrated that three EHVs in the array show the obvious difference in excitation vibration and harvesting performance over single EHV. The lock-in frequency of three EHVs can be enhanced by the EHV array, and the speed bandwidth can be greatly broadened by accounting for 66.9%. The harvesting performance of upstream EHV (EHV-1) and downstream EHV (EHV-3) is significantly improved by the EHV array over single EHV. While, midstream EHV (EHV-2) shows an inhibitory effect to some extent. The overall harvesting performance in the EHV array can be increased by up to 36.23% compared with single EHV in certain spacing distances. The proposed EHV array shows the better harvesting ability over the previous harvesters. This work provides a comprehensive experimental guideline for further designing efficient harvester array used in low-speed water environment.