An Improved Magnetically Bistable Piezoelectric Energy Harvester

By modeling a piezoelectric cantilever beam system in which mechanical bistability emerges from repulsion between a stationary magnet and magnetic tip mass, the size of the basin of attraction for interwell oscillations is increased, so that the higher-energy solutions to the system may be more readily acquired than in previously studied systems. The primary drawback of linear energy harvesters is their very narrow frequency range. Non-linear harvesters provide wider operating frequency regions, but can have coexisting solutions, with the desirable high energy solution usually the more difficult to obtain. Existing work on bistable piezoelectric harvesting systems consider dipole interactions between the magnetic tip mass and an external magnet that is also oscillating at the experimental frequency. This paper demonstrates increased energy generation in transitions between the potential wells of the system through replacing the oscillating independent magnet with a stationary one. Optimizing the system to produce frequent well escapes induced by minimal disturbances from dipole interactions, frequency alterations, or changes in excitation amplitude will aide in achieving the high amplitude solutions of the system. Analytical evaluations of the energy in this system along with simulations of the behavior of the cantilever beam are performed for proof of concept that may be utilized in producing these high amplitude solutions in future experiments.