A piezoelectric energy harvester for multiple natural environments

Abstract

The techniques that harvest energy from natural environments have been considered a promising strategy to implement a sustainable power source for Wireless Sensor Networks. This study proposes a piezoelectric energy harvester for multiple natural environments (MNE-PEH). The MNE-PEH is a compound-type PEH that integrates impact mechanism, centrifugal swing mechanism, and magnetic coupling. An impact mechanism is employed to enhance the output performance of the MNE-PEH. Unlike conventional impact mechanisms, the contact force between the rotor and the stator is replaced by magnetic force, reducing the resistance of rotor. Additionally, a centrifugal swing mechanism is introduced to adjust the excitation frequency of the piezoelectric patches. The structural variables of the MNE-PEH are determined through theoretical analysis, followed by the construction of a prototype and experimental platform. The parameters of the structural variables are optimized during the experiments. Ultimately, when the prototype is assembled with the optimal structural parameters, the root-mean-square voltage (V_rms) and power (P_rms) reach 4.17 V and 4.36 mW when a 4 kΩ resistor is connected in series. In wind energy simulation experiment, the MNE-PEH demonstrated stable operation at a minimum speed of 4.68 m/s. The MN-EPH has vast potential in powering outdoor microelectronic devices.