Triggering the high-energy orbit oscillation of bistable energy harvesters using electrical coupling

As a nonlinear system, bistable energy harvester produces large amplitude vibration and high energy output since it allows the system transit from one stable state to the other. However, it is challenging to activate the high-energy orbit oscillation in ambient environments, where vibration level would be low. This paper proposes a method that an electrical coupling between an electromagnetic energy harvester and a piezoelectric energy harvester is used to help the hybrid system overcome the potential well barrier and maintain in the high-energy orbit. A control switch is employed to electrically connect or disconnect the two energy harvesters. The interaction between them will bring the system from low-energy orbit to high-energy orbit. Benefited from nonlinear features with the coupling, both energy harvesters will stay on the high-energy orbit after the coupling action. Harmonic balance method is employed to demonstrate the multi-solution characteristics of the bistable energy harvester. Furthermore, a coupled model based on Hamilton's principle and Kirchhoff's circuit laws is developed to reveal the jumping phenomenon. Simulation results show that high-energy orbit is achieved and maintained after the coupling. Our proposed solution requires no complex structure design or external power source, so as to provide a feasible and reliable solution to address the critical issue of bistable energy harvesters in practical applications.