关键词: 压电, 俘能器, 多方向, 间接激励, 扭摆激励

Abstract: In order to effectively harvest multi-directional vibration energy， a torsional multi-directional piezoelectric vibration energy harvester（PVEH） was proposed. Both the finite element simulation and experimental evaluation were conducted to figure out the output voltage characteristics of the PVEH. The variation of resonant frequency and the corresponding amplitude at different excitation angles（angle between the excitation direction and the X axis in the XOY plane） is found. The results show that the changes of excitation angles have little influence on the two-order resonant frequency， but have a great influence on the output voltages with different rules. When the excitation angles increased from 0° to 90°， the first-order resonant voltage decreases and the second-order resonant voltage increases； when the excitation angle is as 44°， the two-order resonant voltage is equal. To verify the feasibility of the PVEH used in practical applications， the capacitor charging characteristics and the output power characteristics was studied experimentally. When the PVEH was excited along the X axis and Y axis， the storage energy rates of capacitors may reach 0.58 mJ/s and 0.54 mJ/s respectively. When excited along the X-axis and Y-axis directions， there are two optimal resistances to maximize the output power. On the X-axis excitation direction， there are two optimal resistance values of 17 kΩ and 81 kΩ， corresponding to the output power of 4.56 mW and 3.4 mW， respectively， On the Y-axis excitation direction， there are two optimal resistance values of 17 kΩ and 61 kΩ， corresponding to the output power of 3.96 mW and 3.89 mW， respectively. 

Key words: piezoelectric, energy harvester, multi-direction, indirect excitation, torsional excitation