Design optimization of piezoelectric energy harvesting cantilever for medical devices

Energy harvesting from the human body is considered as an effective solution for powering biomedical systems. In particular, the piezoelectric energy recovery from mechanical vibrations of the human body represents the most promising solution. The harvested power depends on several factors such as the geometry, the size and materials used for the piezoelectric cantilever. In addition, the reduction and the change of the design of the piezoelectric system constitute a process for increasing the output power. In the present paper, the conventional rectangular shape of the piezoelectric energy harvester is studied and different shapes of cantilever are investigated. We introduced thus a triangular and a new shaped cantilever which permits the enhancement of the scavenged power for low frequencies. In addition, simulations result of various structures are compared and performed by employing finite element method (FEM). Simulations results show that the proposed form generates an electric power of 145 µW at resonant frequency of 8.5 Hz. This novel shape provides more efficient performance compared to other designs.