Basic Theory And Key Technologies Of Micro Piezoelectric Wind-induced-vibration Energy Harvester Based On Flutter

The micro power is an effective approach for the micro devices and systemsbecause of small sizes, larger power density, long lifetime and green. And micro powerhas being paid attention to at home and abroad. Recently, lots of researches about themicro power sources focus on harvesting the vibration energy, temperature difference,solar and so on from ambient. However, micro power harvesting wind energy is lessreported. Micro wind energy harvester based on wind-induced vibration has become amajor thrust of research because of simple structure and small size.This paper proposes a micro wind-induced vibration (WIV) energy harvester basedon fluttering. Based on the piezoelectric effect, the oneway coupled lumped parametermodel, oneway coupled distributed parameter model and twoway coupled distributedparameter model about the vibration energy energy harvester were developed andmodified. A new fluttering composite structure consisting of piezoelectric beam andflexible beam was proposed. The linear flutter model and nonlinear flutter model of theWIV energy harvester in axial wind flow were established. The WIV energy harvesterswere designed and three optimized flutter structures were presented: T shape flexiblebeam, blunt structure and upwind structure. The reliability and packaging technologiesabout the WIV energy harvester were studied, and the WIV harvester prototypes weredeveloped. An experimental test platform was built up and the characteristics of theWIV harvester prototypes were measured and analyzed. The RMS output voltage of thedevice is16.4V, the power is3.1mW.The main contributions of this work are listed as follows:①The state of the art about the wind energy harvester was analyzed and thechallenges about the device were developed. A wind-induced vibration energy harvesterusing the fluttering mechanism was proposed.②Using Euler-Bernoulli beam theory, the oneway coupled lumped parametermodel and distributed parameter model were developed for the micro piezoelectricvibration energy harvester. The output performance response was analyzed underdifferent excitation conditions. Using the double piezoelectric effect, the twowaycoupled distributed parameter model was developed and the oneway coupled modelswere modified. The micro piezoelectric vibration energy harvester models were verifiedusing finite element method. ③A new fluttering composite structure consisting of piezoelectric beam andflexible beam was proposed for wind energy harvesting. A linear fluttering model of thecomposite structure in axial flow was developed using unsteady Bernoulli aerodynamictheory and Euler-Bernoulli beam theory, and numerically calculated using Chebyshevcollocation method. Meanwhile a nonlinear fluttering model was developed usingLighthill theory and inextensibility condition, and numerically calculated usingGalerkin method and Houbolt method.④The working wind speed rang was determined. The performance of the WIVharvester, such as fluttering critical wind speed, was studied as a function of flexiblebeam size, and flexible beam size range was determined. The critical wind speeddecreasing method was researched, and three optimized structures were proposed: Tshape flexible beam, blunt structure and upwind structure. The reliability and packagingtechnologies about the WIV energy harvester were studied.⑤The WIV energy harvester prototypes were fabricated and assembled. A smallwind tunnel and a vibration test system were built up. The motion state of the WIVenergy harvester was observe and studied. The prototypes using downwind structure, Tshape flexible beam, blunt structure and upwind structure were measured and resultswere analyzed. The performances of the WIV harvester were measured in differentambient wind.