Frequency Up-Conversion Hybrid Energy Harvester Combining Piezoelectric and Electromagnetic Transduction Mechanisms

A novel hybridization scheme is proposed with electromagnetic transduction to improve the power density of piezoelectric energy harvester (PEH) in this paper. Based on the basic cantilever piezoelectric energy harvester (BC-PEH) composed of a mass block, a piezoelectric patch, and a cantilever beam, we replaced the mass block by a magnet array and added a coil array to form the hybrid energy harvester. To enhance the output power of the electromagnetic energy harvester (EMEH), we utilized an alternating magnet array. Then, to compare the power density of the hybrid harvester and BC-PEH, the experiments of output power were conducted. According to the experimental results, the power densities of the hybrid harvester and BC-PEH are, respectively, 3.53 mW/cm3 and 5.14 μW/cm3 under the conditions of 18.6 Hz and 0.3 g. Therefore, the power density of the hybrid harvester is 686 times as high as that of the BC-PEH, which verified the power density improvement of PEH via a hybridization scheme with EMEH. Additionally, the hybrid harvester exhibits better performance for charging capacitors, such as charging a 2.2 mF capacitor to 8 V within 17 s. It is of great significance to further develop self-powered devices.

Section: Experiments and Discussionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Power Density Improvement of Piezoelectric Energy Harvesters via a Novel Hybridization Scheme with Electromagnetic Transduction

Xin

Peng

et al. 2021

“…The low resonant frequency can be realized by decreasing the structural stiffness or increasing the weight of proof mass, which is easy but may reduce the long-term reliability of devices [ 16 , 17 , 18 ]. A more viable strategy is frequency up-conversion mechanism, in which the targeted vibration is captured by a low-frequency structure and transmitted to a high-frequency oscillator to trigger its free oscillation [ 19 , 20 ]. Consequently, this scheme can well capture the low-frequency vibrations and then realize a high-frequency, efficient mechanical-electrical conversion.…”

Section: Introductionmentioning

confidence: 99%

Multimodal Multidirectional Piezoelectric Vibration Energy Harvester by U-Shaped Structure with Cross-Connected Beams

Jiang

et al. 2022

This paper proposes a multidirectional piezoelectric vibration energy harvester based on an improved U-shaped structure with cross-connected beams. Benefitting from the bi-directional capacity of U-shaped beam and additional bending mode induced by cross-connected configuration, the proposed structure can well capture the vibrations in 3D space at the frequencies lower than 15 Hz. These features are further validated by finite element analyses and theorical formulas. The prototype is fabricated and the experiments under different conditions are carried out. The results show that the proposed harvester can generate favorable voltage and power under multidirectional vibrations at a low operating frequency. Practical applications of charging capacitors and powering a wireless sensor node demonstrate the feasibility of this energy harvester in supplying power for engineering devices.

“…However, the upper limit of efficiency of a single electromechanical system for power generation is low, so adding multiple mechanisms in the device is an effective way to increase the output power [ 26 ]. Currently, more and more scholars are using multiple mechanisms for power generation, such as piezoelectric and electrostatic [ 27 ], electromagnetic and frictional electric [ 28 ], etc.…”

Section: Introductionmentioning

confidence: 99%

“…The above various piezoelectric–electromagnetic hybrid harvesters had a limitation: the vibration frequency of nature is generally low (0–20 Hz), while the vibration response frequency of most of the aforementioned energy harvesters was particularly high, so they would not be effective in practical application for power generation. The current main techniques for energy harvesting in low-frequency environments are frequency up-conversion [ 26 , 36 , 37 ] and multistability [ 38 ]. Soonjae Pyo [ 26 ] et al designed a new up-conversion piezoelectric–electromagnetic hybrid energy harvester consisting of two cantilevers and piezoelectric materials, as shown in Figure 1 b.…”

Section: Introductionmentioning

confidence: 99%

A Magnetically Coupled Piezoelectric–Electromagnetic Low-Frequency Multidirection Hybrid Energy Harvester

Zhu

Zhang

et al. 2022

The traditional single electromechanical conversion energy harvester can collect energy only in a single vibration direction. Moreover, it requires high environmental vibration frequency, and its output power is low. To solve these problems, a cross-shaped magnetically coupled piezoelectric–electromagnetic hybrid harvester is proposed. The harvester comprised a ring-shaped support frame, a piezoelectric generation structure, and an electromagnetic generation structure. The harvester could simultaneously generate energy piezoelectrically and electrically, in addition, it could generate electricity efficiently at a lower environmental vibration, and it can collect the energy in two vibration directions simultaneously. To verify the effectiveness of the device, we set up a vibration experiment system and conducted comparative experiments about non-magnetically coupled piezoelectric, magnetically coupled piezoelectric, and magnetically coupled piezoelectric–electromagnetic hybrid energy harvesters. The experimental results showed that the output power of the magnetically coupled piezoelectric–electromagnetic hybrid energy harvester was 2.13 mW for the piezoelectric structure and 1.76 mW for the electromagnetic structure under the vibration of single-direction resonant frequency. The total hybrid output power was 3.89 mW. The hybrid harvester could collect vibration energy parallel to the ring in any direction. Furthermore, compared with the non-magnetically coupled piezoelectric energy harvester and the magnetically coupled piezoelectric energy harvester, the output power was increased by 141.6% and 55.6%, respectively.