Nonlinear effects of energy harvesting circuit topology on a structure-harvester system

It is predicted that energy consumption will increase by 56% between year 2010 and 2040. To cope with this upcoming energy demand, innovative technologies have been developed in recent decades to harvest energy from the environment such as wind, solar, tide and vibration. Harvesting energy from structural vibration presents two major challenges: efficiency and vibration control. In particular, vibration could be of low and potentially time-varying frequency for large-scale structures. Harvesting energy effectively under such circumstances requires high efficiency transducers and electrical circuits to reduce losses during energy conversion. Most of the previous research however adopted a resistance-inductance model for the electrical circuits which cannot portray the inherent nonlinearity of these electrical circuits. In this study, the nonlinear behavior of a typical energy harvesting circuit, the Standard Energy Harvesting Circuit (SEHC) is modeled. The effect of electromechanical coupling between this energy harvesting circuit and a single-degree-of-freedom structure is then analyzed with the aid of dimensional analysis (DA). The energy dissipation capability and the energy harvesting efficiency of the coupled system are then discussed. An analytical solution for a weakly coupled system under steady-state harmonic excitation is further derived to provide a quick suggestion on the design of an efficient energy harvester for civil engineering structures.