Research On The Composite Vibration Energy Harvester With Spider-web Shaped Plates

As the development of the wireless sensor node(WSN),the technology of medical implanting system,implanting detection system consisted of micro-sensor is more and more mature with the power consumption decreasing into milliwatt or microwatt.Traditional battery technology can not satisfy the need of this type of device or system due to the shortcoming of limited energy storage density,manual changing regularly,etc.Therefore,the energy harvesting technology harvesting energy from the ambient environment which can supply power in the long term is proposed.Common environmental energy includes thermal energy,wind energy,solar energy,vibration energy,etc.Among all of the them,vibration energy has the biggest potential with the characteristic of existing everywhere compared with others.Vibration energy harvester utilizes cantilever structure mostly but utilizes plate structure less.Compared with cantilever structure,plate structure with peripheral fixation has the adventure of steady and damaged hardly,which is more adaptable for supplying the WSN widely implanted into all kinds of hash environment.This paper focuses on the composite mechanism energy harvester with the round plate structure,proposed a spider-web structure based piezoelectric/magnetoelectric energy harvester based on the discuss and analysis of research at home and abroad.For the purpose of enhancing the output power of low frequency environment,a design of the spider-web structure based piezoelectric/magnetoelectric energy harvester is proposed,accomplishing harvesting vibration energy efficiently with weak coupling.The paper studies the influence factor of two mechanism's output power,establishing the Simulink lumped parameter model of single mechanism and composite mechanism combined with elastoplastic mechanics,vibration mechanics and electromechanical equivalent circuit.Analyzing the effect of electromechanical coupling factor on displacement amplitude,eigenfrequency and output power with three kinds of coupling strength of weak,medium,strong coupling in the situation of considering the difference or similarity of the structure equation.It is concluded thatthe round plate structure composite mechanism energy harvester is fit for weak and medium coupling.Proposing the spider-web shape structure as the resonator to decrease the eigenfrequency of the device which is more fit for the common vibration source(tens of Hz or hundreds fo Hz),because of the highest output power of the vibration energy harvester near the eigenfrequency.Study and determine the optimized design plan of the spider-web shaped plate strucuture,utilize FEM software to analyze the eigenfrequency,displacement and output voltage amplitude,having a research on the relationship between parameters of single removing length,removing area percentage,removing angle and statics deflection,eigenfrequency,vibration mode,peak value of the output voltage,equivalent stiffness.Obtain optimized magnet shape and gap in z axis between the magnet and coil.The result shows that decreasing the bonding area of the magnet increases the output of the piezoelectric mechanism;the gap between the coil and magnet in z axis has a position to generate optimized induction voltage.With the setting up of the anti-noise test platform,the optimized spider-shaped structure decreases the eigenfrequency of the energy harvester from 206 Hz to 135 Hz,decreasing by a margin of 33.98%,increasing the output voltage of piezoelectric and magnetoelectric mechanism by a margin of 474.43% and 29.38%,verifying the simulation result that increasing removing area percentage will decrease the eigenfreqeuncy and the characteristic of eigenfrequency decreasing and amplitude increasing.The linear vibration energy harvester has an output of voltage and power of piezoelectric mechanism 39.98 V,1.598mW;magnetoelectric mechanism 277 mV,0.07673 μW in the situation of the resistance load of 10 MΩ,0.8A driving current,weak coupling,which has proven the practicability of accomplishing harvesting low frequency vibration energy efficiently with the proposed composite mechanism energy harvester design plan.Discuss the nonlinear jumping phenomenon discovering in the experiment,propose the next-step plan of enhancing the output power with the application of the nonlinear phenomenon.