Ambient vibration energy harvesters: A review on nonlinear techniques for performance enhancement

A low-frequency, wideband quad-stable energy harvester using combined nonlinearity and frequency up-conversion by cantilever-surface contact

A tunable frequency up-conversion wideband piezoelectric vibration energy harvester for low-frequency variable environment using a novel impact- and rope-driven hybrid mechanism

A two-degree-of-freedom piezoelectric energy harvester with stoppers for achieving enhanced performance

Design and analysis of a multi-step piezoelectric energy harvester using buckled beam driven by magnetic excitation

Piezoelectric energy harvesting techniques provide a promising way to transform the vibration energy into electric energy. Since the voltage output peak can drop due to the frequency excitation moving away from the resonance region, the on broadening the bandwidth of operation frequency has drawn great attention. In the paper, a novel two-degree-of-freedom piecewise-linear piezoelectric energy harvester is proposed to achieve wide operation frequency bandwidth by combining the multimodal harvesting technique and nonlinear method. Based on the average method, the analytical solution of the proposed device is achieved. From analytical and experiment results, at an excitation acceleration of 0.3 g, as the excitation frequency is up sweeping, the system achieves frequency bandwidth operation of 7.4 Hz which is about 5.2 times higher to that of conventional two-degree-of-freedom linear harvester, and the power outputs for the first and second resonances can reach up to 429 μW and 411 μW, respectively. Due to the close agreement between the calculated values and experiment results, the analytical solution and the theoretical model could be applied to further MEMS fabrication process and optimized design.

Theoretical modeling and analysis of two-degree-of-freedom piezoelectric energy harvester with stopper

Piezoelectric vibration energy harvesting technologies have attracted a lot of attention in recent decades, and the harvesters have been applied successfully in various fields, such as buildings, biomechanical and human motions. One important challenge is that the narrow frequency bandwidth of linear energy harvesting is inadequate to adapt the ambient vibrations, which are often random and broadband. Therefore, researchers have concentrated on developing efficient energy harvesters to realize broadband energy harvesting and improve energy-harvesting efficiency. Particularly, among these approaches, different types of energy harvesters adopting magnetic force have been designed with nonlinear characteristics for effective energy harvesting. This paper aims to review the main piezoelectric vibration energy harvesting technologies with magnetic coupling, and determine the potential benefits of magnetic force on energy-harvesting techniques. They are classified into five categories according to their different structural characteristics: monostable, bistable, multistable, magnetic plucking, and hybrid piezoelectric–electromagnetic energy harvesters. The operating principles and representative designs of each type are provided. Finally, a summary of practical applications is also shown. This review contributes to the widespread understanding of the role of magnetic force on piezoelectric vibration energy harvesting. It also provides a meaningful perspective on designing piezoelectric harvesters for improving energy-harvesting efficiency.

https://www.mdpi.com/2072-666X/12/4/436/pdf

A Review of Piezoelectric Vibration Energy Harvesting with Magnetic Coupling Based on Different Structural Characteristics.

The quasi-zero stiffness (QZS) nonlinear isolators have been paid much attention in recent literatures due to their excellent vibration isolation performance under low frequency excitation compared to traditional linear vibration isolators. However, passive QZS isolators are the most widely studied and they are incapable of dealing with varying conditions such as changing the excitation frequency or load in operating state. To promote the adaptability of QZS isolators, a novel approach to achieve real-time controllable quasi-zero stiffness is proposed in this paper. An electromagnetic negative stiffness unit comprised of two electromagnet with MR elastomer is employed to produce negative stiffness, and the stiffness characteristic of the system can be accurately controlled by adjusting the driving current according the displacement information in real time. Theoretical calculation and finite element analysis is conducted to establish the exact model of electromagnetic force followed by the general design of the system. Then a customized driver is developed for electromagnetic negative stiffness unit, and the dynamic model of the isolator is set up to study the effect of relative parameters on the transmissibility. Finally, a series of experiments are performed to evaluate the real-time controllable QZS characteristic and confirm the vibration isolation effect of the proposed electromagnetic QZS isolator.

A real-time controllable electromagnetic vibration isolator based on magnetorheological elastomer with quasi-zero stiffness characteristic

In the past, research of magnetorheological (MR) damper mainly focused on how to improve the damping force, response speed and the performance of its control algorithm With the increasing application of MR dampers in engineering, the adaptability of MR dampers is required to have a greater dynamic range of damping force to achieve better vibration isolation effect in different frequencies In order to satisfy this demand, an outer multi-pole MR damper is proposed in this paper, which adopts the design of multiple electromagnetic poles integrated in cylinder to obtain greater control range of damping force A mathematical model of the damping force is established for the proposed MR damper followed by the general structure design of the MR damper, and optimal design is conducted to determine the main structure parameters 3D analysis of magnetic circuit is conducted utilizing the finite element method, which is used to calculate the magnetic intensity in different areas of the MR damper Based on the data of magnetic simulation, the mechanical characteristics of the MR damper are numerically simulated The proposed MR damper is then manufactured and the damping force characteristics are experimentally investigated and compared with other MR dampers in previous studies The results reveal that the dynamic range of the proposed MR damper is much larger than conventional MR dampers

https://iopscience.iop.org/article/10.1088/1361-665X/aae004/pdf

The development of an outer multi-pole magneto-rheological damper with high dynamic range of damping force

In this work, a magnetic coupling 2-degree-of-freedom bistable piezoelectric energy harvester was designed and developed. The device consisted of a primary beam with a magnet attached to the tip an...

Lifeng Feng

Papers

Theoretical modeling and analysis of two-degree-of-freedom piezoelectric energy harvester with stopper

A Review of Piezoelectric Vibration Energy Harvesting with Magnetic Coupling Based on Different Structural Characteristics.

A real-time controllable electromagnetic vibration isolator based on magnetorheological elastomer with quasi-zero stiffness characteristic

The development of an outer multi-pole magneto-rheological damper with high dynamic range of damping force

Broadband power generation of piezoelectric vibration energy harvester with magnetic coupling