Adaptive synchronized switch harvesting: A new piezoelectric energy harvesting scheme for wideband vibrations

This paper proposes a new energy harvesting architecture that optimizes the energy conversion under broadband vibrations, which is called adaptive synchronized switch harvesting (ASSH) technique. This technique is derived from the enhanced synchronized switch harvesting (ESSH) technique and based on a new and effective switch control law, which can prevent the switch in energy transferring circuit from over-frequent on-and-off and accordingly enhance the extracted power under multimode vibration. Compared with the ESSH technique, theoretical and experimental results demonstrate the new technique can improve electromechanical conversion efficiency when the piezoelectric energy harvester is excited under two-mode vibration, especially in the case of higher vibration amplitude of the second mode. The extracted power with the new technique is more than three times the ESSH technique in the case of the exciting signal of amplitude ratio (3:6). Furthermore, a self-powered circuit which implements the technique (ASSH) is proposed, which validates that the new technique can be truly self-powered, thus addressing the issue of harvesting environmental energy by autonomous devices.