压电俘能器只有在谐振频率附近较窄的频率范围才可获得最佳的功率输出。多个压电俘能器采用阵列连接可实现频率拓宽。该文定义了组成阵列的悬臂梁谐振频率之差Δf_r(即│f_1-f_2│)与单个梁带宽BW(即半功率点对应的带宽)之比,即Δf_r/BW,以其大小来探究阵列悬臂梁的频率差在什么范围内能拓宽阵列频带BWa。并对串、并联阵列进行了理论和实验研究,结果表明,悬臂梁的谐振频率差在一定范围内时,阵列连接既可提高输出功率也可拓宽频带。悬臂梁在该文设计的尺寸和材料内,单个梁的带宽为3.5 Hz时,对于3个梁的并联阵列,Δf_r/BW〈0.657;而串联阵列,Δf_r/BW〈2.571。
The piezoelectric energy harvester obtains the optimal power within a narrow frequency bandwidth nearby its resonant frequency.The multiple piezoelectric energy harvesters(PEHs)can be arranged into an array for widening the frequency bandwidth.The ratio(Δfr/BW)of the frequency differencesΔfr(│f_1-f_2│)to the bandwidth of a single PEH(BW,that is half-power points corresponding bandwidth)has been defined to estimate whether the array could widen the bandwidth(BWa).The series and parallel array PEHs have been studied theoretically and experimentally.The results show that the bandwidth of the single beam is 3.5Hz,theΔfr/BWshould be less than 0.657 when the three PEHs are in parallel,and theΔfr/BW should be less than 2.571 when the three PEHs are in series.Finally,the output voltages amplitude of beams and the phase difference among excitation on output power of array were studied through simulation and experiments respectively.