Magnetic Coupled Cantilever Piezoelectric Energy Harvester

A conventional vibration energy harvester is usually designed as a linear single-degree-of-freedom (1DOF) resonator. The efforts to improve its efficiency involve two aspects, i.e., enlarging the magnitude of output and widening the operating bandwidth. In this paper, we propose a magnetic coupled cantilever piezoelectric energy harvester (PEH) to achieve the above two goals. Different from other reported magnetic coupled PEHs, the magnetic interaction in the proposed design is introduced by a magnetic oscillator. Firstly, the lumped parameter models are established for the conventional linear PEH, the nonlinear PEH with a fixed magnet and the proposed PEH with a magnetic oscillator. The governing equations of the three systems are then provided in the state space form and their dynamics can be simulated by numerical integration. Subsequently, experimental tests are performed to validate the models. Both experiment and simulation show that the dynamics of the magnetic oscillator is able to not only broaden the operating bandwidth but also enhance the maximum power output of the PEH. Based on the validated model, parametric study is conducted to optimize the system performance.