Multi-directional reconfigurable ultra-low frequency vibration energy harvester

Abstract Converting vibrational energy from the environment into electrical energy more efficiently has been one of the key research topics of this century. The majority of vibrations observed in the natural environment occur at low frequencies and are not fixed in direction. This work presents a design of a piezoelectric vibration energy harvester supported by an elastic rod (R-PVEH), which allows for multidirectional responses to capture vibrational energy. The distinctive configuration of the structure allows for a reduction in vibration attenuation in the presence of low-frequency, unstable excitation. Further, in instances where a complex vibration source is present, multiple units can be reconfigurable to achieve a higher and more stable voltage output. The device can output an average voltage of 15.2 V in response to horizontal low-frequency vibrations of 0.3 Hz, representing a 193.3% increase compared to the conventional cantilever beam structure. The device is expected to be employed in multidirectional low-frequency scenarios such as ocean wave energy harvesting.