Modeling and Analysis of VIV-Galloping Coupled Piezoelectric Energy Harvester Shunted to SECE Interface Circuit

This article investigates the performance enhancement of flow-induced vibration piezoelectric energy harvesters through the coupling of vortex-induced vibration (VIV) and galloping. Strips are attached to the surface of cylindrical bluff bodies to induce VIV-galloping coupling, resulting in VIV-galloping coupled piezoelectric energy harvesters (VGPEHs). As voltage outputs from VGPEHs require regulation by interface circuits for practical use, an equivalent circuit model (ECM) is proposed to integrate complex circuits into the analysis. The vortex-induced vibration is described by the wake oscillator equation, with aerodynamic force coefficients derived from computational fluid dynamics simulations. The ECM method is validated through wind tunnel experiments, and further studies explore the power output of the VGPEH shunted to ac, dc, and self-powered synchronous electric charge extraction (SP-SECE) circuits. Both experimental and ECM simulation results show that the SP-SECE circuit provides more stable, though lower, output power across a wide resistance range than the dc circuit. Simulation and limited power theory suggest that the SP-SECE circuit outperforms the dc circuit under weak coupling conditions, but the VGPEH prototype operates under strong coupling conditions. From a practical perspective, a strongly coupled harvester is more cost-effective than a weakly coupled harvester that relies on a complex SP-SECE circuit for power-boosting.