Broadband vibration energy harvester based on nonlinear magnetic force and rotary pendulums

A broadband vibration energy harvester based on nonlinear magnetic force and rotary pendulums is proposed in this paper. The harvester is mainly composed of a magnetoelectric transducer and a rotary pendulum fixed with four permanent magnets. In order to improve the working bandwidth of the harvester, two pairs of permanent magnets are added in the middle of the rotary pendulum by using magnetic nonlinearity. The mechanical-magnetic-electrical analytical model of the harvester is established, and the theoretical value obtained by the model is basically consistent with the experimental value. The results show that the harvester has a strong nonlinearity through the magnetic force. When the acceleration is 0.4 g, some typical testing results are as follows: the resonant frequency is 19 Hz, maximum peak-peak voltage is 94.1 V, half power bandwidth is 15.8 Hz, center frequency is 26.9 Hz, and the ratio of half power bandwidth to the center frequency is 58.73 %.