Performance of a Nonlinear Electromagnetic Energy Harvester–Structure System under Random Excitation

Abstract

Electromagnetic (EM) energy harvesters have been proposed in civil engineering for simultaneous energy scavenging and structural vibration mitigation. One important component governing the performance of EM energy harvester is the energy harvesting circuit. These circuits consist of electronic components that could introduce nonlinearity to the electromechanically coupled harvester–structure system. The presence of this circuit nonlinearity complicates the performance analysis of the harvester–structure system as well as the design of the energy harvesting circuit. In this study, the performance of a structure equipped with an EM energy harvester connected to a representative energy harvesting circuit under Gaussian white noise force excitation is presented. The examined circuit, termed the standard energy harvesting circuit, consists of a full-wave bridge rectifier and a capacitor connected in parallel with a resistor. A statistical linearization technique is adopted to estimate the system’s stationary response. The accuracy of the technique is validated both numerically and experimentally. The results show that neglecting the circuit nonlinearity due to diodes in the full-wave bridge rectifier can result in overestimating both the damping capability of the harvester and the scavenged output power. When the blockage effect of diodes is prevented effectively, the performance of vibration mitigation and energy harvesting can be enhanced simultaneously. The results of this study indicate that neglecting circuit nonlinearity in the analysis could lead to nonoptimal circuit design and could affect the efficiency of energy harvesting.