Research on Output Characteristics of Double-Ended Fixed Beam Piezoelectric Energy Harvester Under Random Excitation

Abstract

By use of the concept of impedance, this paper establishes a random energy harvester output model of double-ended fixed beam piezoelectric energy harvester under random White Gaussian noise excitation, which is based on the discussion of the output characteristics influenced by changing vibration beam shape and piezoelectric sheet length under random excitation, while improving piezoelectric structure of double-ended fixed beam piezoelectric energy harvester. It also deduces the output voltage, current and power of energy harvester with Fokker–Planck equation, which are verified by Monte Carlo simulation and experimental testing. It can be found that improving vibration beam shape can reduce resonant frequency and increase average output power of the system. The optimal value of piezoelectric sheet length can be different corresponding to different structures, which proves that double-ended fixed beam piezoelectric energy harvester under random White Gaussian noise excitation can achieve maximum output with optimal piezoelectric sheet length. In addition, in order to further improve the output performance of piezoelectric energy harvester under random excitation, it is necessary to increase the acceleration spectral density under random excitation and set an optimal value of the piezoelectric loading resistance, which is more suitable for energy harvester applied under random low-frequency environment.