Piezoelectric energy harvesting device optimization by synchronous electric charge extraction

This article presents a nonlinear approach to optimize the power flow of vibration-based piezoelectric energy-harvesting devices. This self-adaptive principle is based on a particular synchronization between extraction of the electric charge produced by the piezoelectric element and the system vibrations, which maximizes the mechanical to electrical energy conversion. An analytical expression of the optimal power flow is derived from a simple electromechanical model. An electronic circuit designed to perform the synchronous charge extraction is proposed. Theoretical predictions confirmed by experimental results show that the new principle increases the harvested power by 400% as compared with a quasilinear impedance adaptation optimization method.