To achieve broadband energy harvesting under weak excitations, this paper comprehensively investigates a novel tri-magnet levitating bistable electromagnetic energy harvester with variable potential wells (BEEH-VP). The bistable nonlinear mechanism is realized using the single-sided bipolarity of the ring magnets. Auxiliary springs are integrated into the ring magnets to dynamically self-adjust the spacing of the ring magnets, causing variable potential wells. The analytical model of BEEH-VP is derived and verified experimentally. The performance of the proposed BEEH-VP is compared with that of the bistable electromagnetic energy harvester with featuring fixed potential wells (BEEH-FP). The comparative results clearly demonstrate that the BEEH-VP exhibits superior capabilities in terms of energy output under weak excitation and possesses a broader frequency bandwidth. Bifurcation analysis for the excitation conditions reveals that the proposed structure features complex dynamic behaviors, such as intra-well, chaotic, harmonic inter-well and subharmonic inter-well vibrations. In comparison to BEEH-FP, BEEH-VP requires lower acceleration to perform the snap-through and has a larger vibration amplitude, facilitating improved output performance.

为了实现弱激励下的宽带能量收集，本文全面研究了一种新型可变势阱三磁体悬浮双稳态电磁能量收集器（BEEH-VP）。双稳态非线性机构是利用环形磁体的单侧双极性实现的。辅助弹簧集成到环形磁铁中，可动态自调节环形磁铁的间距，从而产生可变的势阱。推导了BEEH-VP的分析模型并进行了实验验证。所提出的 BEEH-VP 的性能与具有固定势阱的双稳态电磁能量收集器 (BEEH-FP) 的性能进行了比较。对比结果清楚地表明，BEEH-VP 在弱激励下的能量输出方面表现出优异的能力，并且具有更宽的频率带宽。激励条件的分岔分析表明，所提出的结构具有复杂的动态行为，例如井内振动、混沌振动、井间谐波振动和井间次谐波振动。与BEEH-FP相比，BEEH-VP需要更低的加速度来执行突弹，并且具有更大的振动幅度，有利于提高输出性能。