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

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.