This paper presents a planar architecture implementing dual-nonlinearity mechanism for broadening bandwidth of a two-degree-of-freedom MEMS energy harvester. The proposed device consists of an electromagnetic-based inner resonator for power generation, and an outer resonator for accessory frequency tuning. In comparison with conventional 2DOF configuration, different high-order nonlinearity is subjected to the first two resonances by nonlinear springs incorporated into the inner and outer resonator, respectively, achieving double hardening responses with increased bandwidth at elevated excitation. Moreover, independent tuning of the resonant frequency and working bandwidth of both resonances could be achieved through concordant control of inner and outer nonlinear resonator, and with further adjust of mass and frequency ratio, the low-efficiency power generation range separating adjacent resonances could be effectively reduced. It’s numerically shown that with proper nonlinearity at both oscillation stages, the approximate convergence of two nonlinear resonances with broadband and narrow low-efficiency range could be achieved following the mass ratio of $\mu < 0.07$ and linear frequency ratio of $0.7 < \alpha < 1$ between inner and outer stage. At acceleration of 1 g, test result further confirms that under dual-nonlinearity with nonlinearity ratio of 0.5, a continuous energy harvesting spectrum covering two nonlinear responses is realized with mass ratio of 0.02 and frequency ratio of 1, showing 3-dB bandwidth of 65 Hz. Power output of $127.7~\mu \text{W}$ and normalized power density of $1064~\mu $ Wcm $^{-3}\text{g}^{-2}$ are achieved with the optimum load resistance of $37.5~\Omega $ . This mechanism could be further applied to multi-DOF VEH for ultra-wide bandwidth of energy harvesting. [2020-0231]

中文翻译：

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MEMS多模态能量收集器带宽扩展双非线性机制的实现

本文提出了一种实现双非线性机制的平面架构，用于拓宽二自由度 MEMS 能量收集器的带宽。所提出的设备由用于发电的基于电磁的内部谐振器和用于辅助频率调谐的外部谐振器组成。与传统的 2DOF 配置相比，不同的高阶非线性分别受到内谐振器和外谐振器中的非线性弹簧的前两个谐振的影响，在高激励下实现双硬化响应，带宽增加。此外，通过内外非线性谐振器的协调控制，并进一步调整质量和频率比，可以实现两个谐振的谐振频率和工作带宽的独立调谐，可有效减少隔开相邻谐振的低效发电范围。数值结果表明，在两个振荡级都具有适当的非线性，按照质量比可以实现宽带和窄低效率范围的两个非线性谐振的近似收敛。 $\mu < 0.07$ 和线性频率比 $0.7 < \alpha < 1$ 内外舞台之间。在1 g加速度下，测试结果进一步证实，在非线性比为0.5的双非线性下，实现了质量比为0.02，频率比为1的连续能量收集谱覆盖两个非线性响应，显示3-dB带宽为65赫兹。功率输出 $127.7~\mu\text{W}$ 和归一化的功率密度 $1064~\mu $ 水箱 $^{-3}\text{g}^{-2}$ 是通过最佳负载电阻实现的 $37.5~\Omega $ . 这种机制可以进一步应用于多自由度车辆，以实现超宽带宽的能量收集。[2020-0231]