Study On Efficient Piezoelectric Wind Energy Harvesting Device Based On Galloping Effect

With the rapid developments of micro/nano electromechanical system,wireless communication,and other technologies,wireless sensor network is emerged as the time requirements,which appears an important application value in the environmental monitoring,disaster warning,military reconnaissance,and other fields.However,most wireless sensor network nodes currently rely on batteries as power suppliers.A large amount of usage will cause serious environmental pollution.The cost of maintenance will also be increased due to battery recharging and replacement.All of these become the key factor hindering the extensional applications of wireless sensor network technology.Along with the developments of low power sensing,processing,and communication devices,it becomes possible to harvest weak energy of environment for the power supply of sensor nodes,and self-powered wireless sensor system becomes a hot topic in scientific research and engineering application.Since wind energy is a clean renewable energy source widely existed in nature,developing efficient wind energy harvesting devices for wireless sensor network nodes in special environments has broad application prospects.In order to effectively improve the efficiency of wind energy harvesting,this paper proposes an efficient piezoelectric wind energy harvesting device based on the galloping effect.The main research work completed as the following:(1)Basic principles of energy harvesting based on wind induced vibration and optimization approaches of piezoelectric cantilever beam structure are summarized,so that theoretical bases of L-shaped piezoelectric cantilever beam wind energy harvesting based on the galloping effect are established.(2)Modal and fluid-solid coupling simulations of straight and L-shaped cantilever beam wind energy harvesting structures are conducted respectively.The inherent frequencies,resonant vibration shapes,and fluid-solid coupling characteristics of the two devices are compared.Simulations of standard energy harvesting circuit are also conducted to analyze of the influence laws of circuit parameters on energy harvesting.(3)Prototypes of straight and L-shaped piezoelectric cantilever beam wind energy harvesting devices are fabricated,and experimental test platform simulating wind energy harvesting is set up.Working characteristics of the galloping effect is tested with straight cantilever beam.Wind energy harvesting characteristics of L-shaped piezoelectric cantilever beams are tested and compared.Influences of electrical parameters of circuit on energy harvesting performances are also tested.(4)Experimental results show that: Installation angle of upwind has a great influence on cut on wind speed and output voltage;appropriate length ratio of L-shaped piezoelectric cantilever beam can obtain a lower cut on wind speed and wide wind speed range;wind energy harvesting device with L-shaped cantilever beam has better harvesting performance than straight cantilever beam.Under a wind speed of 6 m/s and a matching load of 0.5 M?,the L-shaped cantilever beam wind energy harvesting device with a size of(50 + 45)mm × 20 mm × 0.3 mm can product 1.3 mW output power,which is twice compared with straight cantilever beam.It also can product 0.9 mW output power with the standard piezoelectric energy harvesting circuit.In conclusion,the proposed L-shaped cantilever beam wind energy harvesting device based on galloping effect has an excellent wind energy conversion performances and can be used to power wireless sensor network nodes in special area with abundant wind energy.