A piezoelectric wind energy harvester excited indirectly by a coupler via magnetic-field coupling

• Published in: Energy conversion and management 2021-07, Vol.240, p.114250, Article 114250
• Main Authors: Kan, Junwu, Liao, Weilin, Wang, Shuyun, Chen, Song, Huang, Xin, Zhang, Zhonghua
• Format: Article
• Language: English
• Subjects: Adaptability; Bandwidths; Beams (structural); Couplers; Coupling; Cylinders; Electric potential; Energy; Energy harvesting; Galloping; Indirect excitation; Load resistance; Magnetic-field coupling; Magnets; Network reliability; Piezoelectric transducers; Piezoelectric wind energy harvester; Resonant frequencies; Vibration; Voltage; Vortex-induced vibration; Vortex-induced vibrations; Wind effects; Wind power; Wind speed; Wireless sensor networks
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2021.114250

•An indirectly-excited piezoelectric wind energy harvester via a coupler is presented.•Piezo-vibrator sealed in a chamber is indirectly excited by magnetic-field coupling.•Reliability is improved by the combination of sealed structure and magnetic coupling.•The wide effective wind-speed bandwidth brings good environment adaptability.•Power generation performance can be enhanced by altering the structural parameters. Energy harvesting from wind-induced vibration energy using piezoelectric materials has received great attention because of the self-powered demand for wireless sensor networks. To improve the reliability, output performance and environmental adaptability (or designability of the structure), a piezoelectric wind energy harvester excited indirectly by a coupler via magnetic-field coupling (MC-PWEH) is proposed in this paper. The MC-PWEH is mainly composed of a piezoelectric transducer and a coupler consisting of a flexible beam, a cylinder, some exciting magnets and added coupler mass. By introducing the interaction of the piezoelectric transducer sealed in the chamber and the cylinder via the magnetic coupling, the interactive vortex-induced vibration (VIV) and galloping is realized and the composite vibration energy is transformed into electric energy. The feasibility of the structure and principle of the MC-PWEH is proved through theoretical simulations and experiments. The results indicated that the piezoelectric transducer began to oscillate strongly and generate fairly high output voltage when the wind speed exceeded a low critical wind speed, accompanied by a coupling phenomenon of VIV and galloping, and then finally converged to a stable value when the wind speed exceeded a high critical value. Moreover, the critical wind speeds, bandwidth of wind speed, natural frequency and power generation performance of the MC-PWEH could be adjusted by changing the structural parameters. Under the transducer proof mass of 50 g, the optimal wind speed bandwidth for the MC-PWEH to output voltage greater than 3.5 V obtained was 25.84 m⋅s−1 that occupies 86.12% of the experimental wind speed bandwidth. The achieved maximum output power was 4.73 mW at the optimal external load resistance of 1000 kΩ and wind speed of 24 m⋅s−1.