Enhanced magnetically coupled rotational piezoelectric energy harvesting based on tailored centrifugal distance

Abstract

To tackle the issue of limited operating bandwidth encountered by energy harvesters in high-speed rotating contexts, this paper proposes a method for achieving rotational energy harvesting over a relatively high bandwidth through stabilizing high-energy orbit oscillations based on theoretically tailored centrifugal distance. The interaction between the cantilever beam tip permanent magnet and the fixed end magnet introduces nonlinear factors into the rotating piezoelectric energy harvesting system. By exploiting the non-linear matching relationship between the jump-down frequency under bistable condition and the rotational frequency of the external environment, the centrifugal distance theoretically derived is divided into five distinct conditions. Notably, when the centrifugal distance is in condition of 6.5 cm, optimal alignment and overlap are observed between the jump-down curve and the rotational frequency curve within the rotational frequency range of 40–80 rad s−1. Tailoring of different centrifugal distances across the five conditions is then explored and validated through simulations, including velocity profiles and energy harvesting capabilities. Finally, a rotating experimental platform was constructed and the experimental results validate that, at the theoretically tailored centrifugal distance of 6.5 cm, the rotating energy harvester achieves a peak power output of 127.4 μW within the effective bandwidth of 40–80 rad s−1. This study underscores the significance of tailoring centrifugal distance to stabilize high-energy orbit oscillations, thereby enhancing the energy harvesting potential of the device across a relatively wide range of external rotational frequencies.