扭摆式多方向压电振动俘能器的研究

Research on Torsional Multi-directional Piezoelectric Vibration Energy Harvesters

为实现多方向振动能量回收,提出了一种扭摆式多方向压电振动俘能器,并从有限元仿真与试验两方面对其输出电压特性进行研究,获得了不同激励角(激励方向与X轴在XOY面内的夹角为激励角)时的谐振频率及其所对应幅值的变化规律。研究结果表明,激励角变化对两阶谐振频率影响均较小,但对输出电压的影响较大且影响规律不同;激励角从0°增加到90°时,一阶谐振电压减小、二阶谐振电压增大,激励角为44°时两阶谐振电压相等。在此基础上,进行了电容充电特性及输出功率特性的试验研究。沿X轴和Y轴方向激励时,电容的存储能速度分别达0.58 mJ/s和0.54 mJ/s;沿X轴和Y轴方向激励时,均存在两个最佳电阻使输出功率最大,即沿X轴方向激励时的最佳负载和最大功率分别为(17,81)kΩ和(4.56,3.4)mW,沿Y轴方向激励时的最佳负载和最大功率分别为(17,61)kΩ和(3.96,3.89)mW。

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 kΩand 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 kΩand 61 kΩ,corresponding to the output power of 3.96 mW and 3.89 mW,respectively.