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Efficiency of energy conversion for a piezoelectric power harvesting system

2006; IOP Publishing; Volume: 16; Issue: 11 Linguagem: Inglês

10.1088/0960-1317/16/11/026

1361-6439

Yi-Chung Shu, I. C. Lien,

Wireless Power Transfer Systems

This paper studies the energy conversion efficiency for a rectified piezoelectric power harvester. An analytical model is proposed, and an expression of efficiency is derived under steady-state operation. In addition, the relationship among the conversion efficiency, electrically induced damping and ac–dc power output is established explicitly. It is shown that the optimization criteria are different depending on the relative strength of the coupling. For the weak electromechanical coupling system, the optimal power transfer is attained when the efficiency and induced damping achieve their maximum values. This result is consistent with that observed in the recent literature. However, a new finding shows that they are not simultaneously maximized in the strongly coupled electromechanical system.