A magnetoelectric heterostructure employing a magnetic levitation mechanism for harvesting low-frequency vibration energy

Abstract

A magnetoelectric (ME) heterostructure using shear-mode ME transducers to extract ambient low-frequency vibration energy is proposed. The demand for the traditional mechanical spring is eliminated by utilizing a magnetic levitation mechanism. When the suspending magnet moves relative to the ME transducers, the piezoelectric plates deform in shear mode owing to the magnetostriction of the magnetostrictive plates, and large shear piezoelectric effect is induced. Consequently, larger voltages can be produced by the presented device. The kinetic equation of the energy harvesting system is derived and solved, and the maximum output power is obtained based on the vibration rule and the variation of the sensed magnetic field. The feasibility of the heterostructure is experimentally verified. The maximum load power increases with acceleration. A maximum output power of 1.46mW is generated across a 1.25MΩ resistive load at the acceleration of 0.7g. The generated energy of the heterostructure is sufficient to drive a low-power electronic device. Improvements are feasible, which allow an obvious increase of the maximum output powers by employing a Halbach array with a particular arrangement of the magnets.