Poly-stable energy harvesting based on synergetic multistable vibration

In this study, the external load resistance of a magnetically coupled two-degree-of-freedom bistable energy harvester (2-DOF MCBEH) was optimized to maximize the harvested power output, considering the third-harmonic distortion in forced response. First, the nonlinear dynamic analysis was performed to investigate the characteristics of the large-amplitude interwell motions of the 2-DOF MCBEH. From the analysis results, it was found that the third-harmonic distortion occurs in the interwell motion of the 2-DOF MCBEH system due to the nonlinear magnetic coupling between the beams. Thus, in this study, the third-harmonic distortion was considered in the optimization process of the external load resistance of the 2-DOF MCBEH, which is different from the process of conventional impedance matching techniques suitable for linear systems. The optimal load resistances were estimated for harmonic and swept-sine excitations by using the proposed method, and all the results of the power outputs were in excellent agreements with the numerically optimized results. Furthermore, the associated power outputs were compared with the power outputs obtained by using the conventional impedance matching technique. The results of the power outputs are discussed in terms of the improvement in energy harvesting performance.

“…Enhancing broadband performance is of importance when designing VEHs [ 32 ]. Herein, for quantitative comparisons of broadband performance, average RMS power, denoted by

, is introduced.…”

Section: Resultsmentioning

confidence: 99%

Load Resistance Optimization of a Magnetically Coupled Two-Degree-of-Freedom Bistable Energy Harvester Considering Third-Harmonic Distortion in Forced Oscillation

Noh

Kim

Yoon

2021

“…Furthermore, the linear multiple DOF oscillators generally have narrow operating bandwidth. (3) Coupled oscillators’ structure [19,20,21,22] usually denotes the same generating elements coupled by magnetic interaction. This magnetic interaction contributes to exciting high-energy oscillations of oscillators and improves the output power.…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of a Magnetically Coupled Multi-Frequency Hybrid Energy Harvester

Hong

Zhang³

et al. 2019

The approach to improve the output power of piezoelectric energy harvester is one of the current research hotspots. In the case where some sources have two or more discrete vibration frequencies, this paper proposed three types of magnetically coupled multi-frequency hybrid energy harvesters (MHEHs) to capture vibration energy composed of two discrete frequencies. Electromechanical coupling models were established to analyze the magnetic forces, and to evaluate the power generation characteristics, which were verified by the experimental test. The optimal structure was selected through the comparison. With 2 m/s2 excitation acceleration, the optimal peak output power was 2.96 mW at 23.6 Hz and 4.76 mW at 32.8 Hz, respectively. The superiority of hybrid energy harvesting mechanism was demonstrated. The influences of initial center-to-center distances between two magnets and length of cantilever beam on output power were also studied. At last, the frequency sweep test was conducted. Both theoretical and experimental analyses indicated that the proposed MHEH produced more electric power over a larger operating bandwidth.

“…So, a new type of energy harvester based on vibration energy collection has been widely studied. Vibration energy harvesting is mainly based on electromagnetic [2][3][4][5][6], electrostatic [7,8], triboelectric [9,10], and piezoelectric [11][12][13] conversion mechanisms. Among them, the piezoelectric vibration energy harvester (PVEH) has been widely studied due to its simple structure, high energy density, excellent voltage output, and easy integration with other devices.…”

Section: Introductionmentioning

confidence: 99%

A Direction Self-Tuning Two-Dimensional Piezoelectric Vibration Energy Harvester

Zhao

Wei

Zhong

et al. 2019

Most work from the last decade on the piezoelectric vibration energy harvester (PVEHs) focuses on how to increase its frequency bandwidth but ignores the effect of vibration direction on the output performance of the harvester. However, both the frequency and the direction of the vibration in a real environment are time-variant. Therefore, improving the capability of PVEH to harvest multi-directional vibration energy is also important. This work presents a direction self-tuning two-dimensional (2D) PVEH, which consists of a spring-mass system and a direction self-tuning structure. The spring-mass system is sensitive to external vibration, and the direction self-tuning structure can automatically adjust its plane perpendicular to the direction of the external excitation driven by an external torque. The direction self-tuning mechanism is first theoretically analyzed. The experimental results show that this direction self-tuning PVEH can efficiently scavenge vibration energy in the 2D plane, and its output performance is unaffected by vibration direction and is very stable. Meanwhile, the effect of the initial deflection angle and the vibration acceleration on the direction self-tuning time of the PVEH is investigated. The direction self-tuning mechanism can also be used in other PVEHs with different energy conversion methods for harvesting multi-direction vibration energy.