Analyses of impedance matching for piezoelectric energy harvester with a resistive circuit

Abstract

To investigate resistance matching and the power optimality performance of the piezoelectric energy harvester connected to a resistance circuit, an analytical solution for the bimorph piezoelectric energy harvester based on the piezoelectric constitutive equations and the fundamental mechanics of materials relations is done to estimate the maximum achievable power and the optimal resistance. A finite element model for system-level simulation is constructed to analyze the effect of the various load resistance on output power around the resonance frequency. Furthermore, the internal impedance of the energy harvester is obtained from a harmonic alternating voltage input using the finite element method (FEM). The simulation results were found to be in agreement with numerical calculation results. The results indicate that the output power depends on the internal impendence of the piezoelectric energy harvester, and the impedance matching can be used to extract maximum output power.

A miniaturized electromagnetic energy harvester with volt-level output based on stacked flexible coils

“…Therefore, for a same 100 Ω of resistance change, it is only 10.5% of the coil resistance of the proposed EVEH, but already more than 100% of the coil resistance of the commonly reported EVEH devices, whose coil resistance is usually less than 100 Ω. The energy harvester device outputs maximum power when its internal resistance matches the resistance of the load [14,15]. Therefore, it is advantageous for the EVEH to have the capability to output high power in a wide resistance range, in order to adapt to different applications.…”

Performance optimization for cantilevered piezoelectric energy harvester with a resistive circuit

“…In some previous literatures, this solution method was used to study the performance of the cantilevered-type piezoelectric energy harvester including the effect of the physical and geometrical parameters on the power output [4], the wideband capability of the connected piezoelectric bimorph [5] and the resonance frequency tuning capability for the segmented piezoelectric energy harvester through the circuit connection patterns [6]. In a recent literature, using this analytical model, Wang et al [7] studied the resistive impedance matching between the piezoelectric bimorph and the load resistance around the short circuit and open circuit resonance frequencies. They obtained the optimal load resistance for maximal power outputs of the energy harvester and pointed out the simple impedance matching method used in some prior studies [8]- [9] was inaccurate.…”