In this study, a novel broadband piezoelectric vibration energy harvester (VEH) is constructed using piecewise nonlinearity. The VEH consists of a piezoelectric cantilever beam and a cylindrical cam-roller-spring structure that can produce negative stiffness and piecewise nonlinearity. The designed piecewise nonlinear force consists of two sections. The first section keeps the nonlinear force small, so that the VEH generates a high peak power, and the second section makes the nonlinear force increase sharply, so that the VEH has a wide bandwidth. Therefore, the designed VEH has higher peak power and wider bandwidth than those VEHs based on smooth magnetic nonlinearity or spring nonlinearity. Firstly, a dynamic model is developed and the steady-state periodic responses are obtained by the average method. Then, the influences of the structure parameters of the cam-roller-spring on the performance of the VEH are studied. The results show that compared with the linear system, the piecewise nonlinearity can increase the peak voltage from 28.9 to 64.6 V, increasing by 123%; it can increase the peak power from 0.84 to 4.17 mW, increasing by 396%; and it can increase the operating frequency range from 0.99 to 6.48 Hz, increasing by 554%. Finally, the energy harvesting performance of the designed VEH is compared with the widely used magnet-type and spring-type VEHs, in which the nonlinear forces are smooth. The results show that the proposed VEH has a 9.67% increase in peak power, a 79.2% increase in the frequency band, and a 4.2% increase in maximum efficiency than the magnet-type VEH; and has a 23.5% increase in peak power, a 5.01% increase in the frequency band, and an 8.8% increase in maximum efficiency than the spring-type VEH.

在这项研究中，使用分段非线性构造了一种新型宽带压电振动能量收集器 (VEH)。VEH 由压电悬臂梁和圆柱凸轮滚子弹簧结构组成，可以产生负刚度和分段非线性。设计的分段非线性力由两部分组成。第一段保持非线性力较小，使 VEH 产生较高的峰值功率，第二段使非线性力急剧增加，使 VEH 具有较宽的带宽。因此，与基于平滑磁非线性或弹簧非线性的 VEH 相比，设计的 VEH 具有更高的峰值功率和更宽的带宽。首先，建立了动力学模型，并通过平均法获得稳态周期响应。然后，研究了凸轮-滚子-弹簧的结构参数对VEH性能的影响。结果表明，与线性系统相比，分段非线性可将峰值电压从28.9 V提高到64.6 V，提高了123%；可将峰值功率从0.84 mW提高到4.17 mW，提高396%；它可以将工作频率范围从0.99增加到6.48Hz，增加554%。最后，将设计的 VEH 的能量收集性能与广泛使用的磁体型和弹簧型 VEH 进行比较，其中非线性力是平滑的。结果表明，与磁体式VEH相比，所提出的VEH峰值功率提高了9.67%，频段提高了79.2%，最大效率提高了4.2%；并且峰值功率增加了 23.5%，为 5。