Synchronized charge extraction in galloping piezoelectric energy harvesting

Energy harvesting from aeroelastic instabilities has attracted numerous interests with the purpose of implementing self-powered wireless sensing networks. Meanwhile, considerable efforts have been devoted to optimizing the interface circuit to boost the power output from vibration-based piezoelectric energy harvester, such as impedance matching, synchronized charge extraction, and synchronized switching harvesting on inductor. However, application of these circuits in aeroelastic energy harvesting has received far less attentions. With an experimentally validated equivalent circuit model, this article investigates the feasibility of employing the synchronized charge extraction interface for a galloping-based piezoelectric energy harvester. The performance of synchronized charge extraction circuit is compared with a standard circuit, revealing three main advantages of synchronized charge extraction in galloping-based piezoelectric energy harvester system: first, the output power from synchronized charge extraction is independent of electrical load, eliminating the requirement of impedance matching and thus ensuring the flexibility of adjusting the galloping-based piezoelectric energy harvester system for practical applications; second, the synchronized charge extraction circuit helps to save piezoelectric materials by 75% compared to the standard circuit; and third, the displacement amplitude of galloping-based piezoelectric energy harvesters with synchronized charge extraction is much smaller, alleviating the fatigue problem and enhancing the durability of the harvesting system. Finally, a theoretical criterion is proposed to determine the applicable region of synchronized charge extraction in galloping-based piezoelectric energy harvester.