Modeling and Analysis of a Nonlinear Lever-Type Energy Harvester in Series With the RLC Circuit Under Low-Frequency Excitation

Abstract Bistable vibration energy harvesters have been comprehensively and thoroughly studied for their outstanding energy harvesting capabilities. The lever mechanism offers a straightforward and effective solution for realizing bistable systems. Neglecting dynamical characterization of such harvesters would lead to unanticipated nonlinear behaviors that impair performance. Thus, this paper proposes a nonlinear lever-type vibration energy harvester with a series-connected RLC circuit. First, a bistable energy harvester is designed by introducing negative stiffness. The theoretical model has been established and is validated by numerical and experimental results. Second, the relationship between the equivalent stiffness and the magnet space is studied, based on which dynamic responses under different magnet spaces are then analyzed by the bifurcation diagram. According to the Poincaré map, chaos can be perceived. The cause of the chaos is figured out as a period-doubling bifurcation through the phase trajectory. Third, potential energy with various lever pivot positions is compared, indicating that a higher potential energy well leads to interwell oscillations, and chaos is highly related to the pivot position. Finally, the power generated is discussed by altering the RLC circuit's resonant frequency and resistance value. The average power is capable of achieving 3.22 mW. Overall, this paper establishes the theoretical foundation for investigating the dynamic characteristics of lever-based bistable energy harvesters, as well as the influence of RLC circuit loading on power output performance.