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

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 k Omega and wind speed of 24 m.s (-1).

Automated summary

A piezoelectric wind energy harvester excited indirectly by a coupler via magnetic-field coupling is proposed in this paper, which can transform composite vibration energy into electric energy; The feasibility of the structure and principle of the harvester is proved through theoretical simulations and experiments, and it is found that the performance of the harvester can be adjusted by changing the structural parameters.