A method to enhance the nonlinear magnetic plucking for vibration energy harvesters

In this work, a technique to improve the magnetic plucking for frequency up-conversion in piezoelectric energy harvesters is presented. The technique involves shielded magnets with Neodymium-iron-boron alloy polarized in the opposite direction on a main magnet. The phenomenon is investigated both at the computational and at the experimental level. Subsequently, simulations on a mesoscale piezoelectric energy harvester are presented which demonstrate a gain of 17 times if the magnets are shielded in comparison with the classical plucking (i.e. without shielding). The technique finds useful applications and benefits in the field of low-speed and low-frequency vibration energy harvesting, as well as in actuation and sensing.