An easily-started piezoelectric wave energy harvester based on collective excitation of multilayer piezoelectric vibrators

Due to their inherent mismatch with low-frequency, irregular ocean waves, piezoelectric wave energy harvesters suffer from insufficient output power and poor working adaptability. This paper proposes an easily-started piezoelectric wave energy harvester based on the collective excitation of multilayer piezoelectric vibrators. The device mainly consists of power generation units that use a magnetic coupling mechanism to excite multilayer piezoelectric vibrators and a power take-off unit that includes a drive wheel and other structures. Based on the working principle of the device, theoretical analysis is conducted on its magnetic and mechanical characteristics. The structure of the drive wheel is optimized to reduce the start-up force of the device to 2.56 ± 0.06N. Furthermore, simulation wave experiments, wave tank experiments, and practical application tests were conducted. The results show that the peak voltage of the device is 5.4 times higher than that of a single-layer piezoelectric vibrator. Under a wave frequency of 2.0 Hz and a wave height of 100 mm, the peak power of the device reaches 2.27 ± 0.03 mW at 0.1 MΩ. Finally, in the real ocean environment, it can power SOS warning lights and wireless sensors. This study provides references for improving the output performance of piezoelectric wave energy harvesters and their adaptability to wave excitation.