A new type of piezoelectric self-excited vibration energy harvester for micro-actuator's energy storage

In this paper, a new type of potassium-sodium niobate (K0.5Na0.5NbO3, KNN) piezoelectric self-excited vibration energy harvester (VEH) for micro-actuator's energy storage is proposed, and the system's nonlinear dynamic characteristics are studied. The KNN piezoelectric VEH has self-excited vibration characteristics, which can convert the random vibration energy from the environment into the harmonic currents for storage. New nonlinear differential terms are introduced to describe the hysteretic phenomena of a KNN piezoelectric ceramics. The nonlinear dynamic model of a KNN piezoelectric VEH subjected to stochastic disturbance is developed, the stochastic stability of the system is analyzed, and the conditions of stochastic bifurcation are obtained. The numerical results show that the system's motions can keep periodic when the outside random excitation is not very strong. The experimental results show that the KNN piezoelectric VEH can convert the harmonic excitation to harmonic currents, and the maximum output voltage is 237.99mv; there is a certain platform in the acceleration-output voltage curves of the system, which implies that there is an optimal amplitude for excitation force; the KNN VEH can convert the narrowband excitation to the narrowband currents, and the maximum output voltage is 572.89mv; the KNN VEH successfully convert a Gauss white noise excitation to narrowband currents, and the maximum output voltage is 99.35mv. The new KNN self-excited VEH can obtain the narrowband currents from the environment, which implies a new way to obtain green energy. © 2021 Elsevier Ltd. All rights reserved.