A nonlinear magnetic-collision coupled piezoelectric energy harvester with lever amplification for enhanced power generation under lowfrequency excitation

Abstract Low frequency energy, as a form of energy that is commonly found in the environment, is difficult to harvest and utilize effectively. This paper presents a nonlinear magnetic-collision coupled piezoelectric energy harvester with lever amplification for enhanced power generation under low-frequency excitation (magnet-collision coupled piezoelectric energy harvester). By incorporating a double-sided stopper, a piecewise nonlinear stiffness (collision nonlinearity) is introduced, while magnets are installed inside the stopper to generate nonlinear magnetic forces. The impact of magnetic force and the stopper on the performance of the device at low frequencies is investigated. The lever can enhance the displacement, allowing the piezoelectric sheet to undergo a bi-stable snap-through motion with ease. While the stopper enhances the deformation of the piezoelectric sheet under low frequency conditions, significantly improving its voltage output performance. The comprehensive motion state and energy collection performance of the device have been studied. The results indicate that under low frequency excitation, compared to the structure without magnet, this device increases the output voltage by 78.02% (29.81 V → 53.07 V) compared to the structure without stopper, this device increases the output voltage by 101.78% (26.3 V → 53.07 V). When the energy harvester operates at the optimal variable (lever ratio α = 2, magnet spacing d = 3 mm, spring wire diameter D = 0.6 mm), the output power is 56.01 mW (external resistance 30 kΩ).