Adjusting the resonant frequency of a segmented energy harvester through circuit connection patterns

We propose a segmented piezoelectric energy harvester in the flexural mode for scavenging ambient vibration energy. 4 circuit connection patterns between segment piezoelectric bimorphs are presented. The resonant frequency of a segmented piezoelectric harvester is readily adjusted through changing either its geometrical configuration or circuit connection pattern, which can keep the harvester operating at the optimal state in environment with different ambient vibrations. The governing equations of a segmented piezoelectric harvester with alternate bimorphs are derived from the transfer-matrix technique. The numerical results show that the adaptability of a harvester to the operating environment can be improved greatly by designing the harvesting structure with adjustable resonant frequency.