Analysis For Output Power Characteristics Of Resonant Flexoelectric Cantilever Beam

The development of new functional materials and energy harvesting devices with high energy conversion efficiency,and the development of new environmental energy harvesting technologies to realize the energy self-sufficiency of small integrated electronic devices are particularly necessary for the upgrading of green energy utilization and intelligent manufacturing in my country.The flexoelectric effect sensitive to strain gradient is widely used in dielectric materials,which has the advantages of scale sensitivity,green environment protection,no prepolarization,no special requirements for crystallinity and working temperature of the materials and has a wide application prospect in the fields of driving,sensing and energy collection.This paper takes the flexural electrical energy harvesting cantilever structure as the research object,analyzes the influence of structural parameters and load electrical parameters on its energy conversion efficiency,studies the ways to increase the effective output power of the load and provides a design for the flexural electrical cantilever energy harvester basis and parameter optimization program.The specific research contents are as follows:Preparation and characterization of flexoelectric materials.Barium strontium titanate samples were prepared by solid state method;the experimental platform of flexoelectric characteristics is built by using exciter,laser displacement meter,lock-in amplifier and other equipment,which provides the experimental technical basis for the measurement of flexoelectric coefficient and energy collection of BST sample.Analysis of structural parameters of flexure electric cantilever energy collector.Based on the Gibbs free energy density function considering the size effect and Hamilton principle,the vibration control equation of the flexure electric cantilever beam is established;with the help of modal analysis,the voltage and power frequency response functions of the cantilever structure are obtained;the resonant frequency of flexure cantilever structure is analyzed by power frequency response.The results show that the load impedance matches the internal impedance of the energy collector and the output power of the load is the highest when the ambient excitation frequency is close to the resonance frequency of the structure;the load resistance forms a negative feedback regulation with the actual resonant frequency of the structure and the optimal working condition of the energy collector is designed after the saturation frequency shift,so as to avoid the deviation of the structural resonant frequency from the ambient excitation frequency,which is conducive to improving the efficiency of capturing mechanical energy of the energy collector.Analysis of electrical parameters of flexure cantilever energy collector.By adjusting the phase difference between the circuit oscillation and the flexure cantilever vibration,the energy storage capacity of the inductor is enhanced,the reverse flexure effect of the transducer is weakened and the effective output power of the energy collector is objectively improved;the load output power of BST cantilever structure is tested under the conditions of no rectifier circuit,classical rectifier circuit and parallel synchronous switched inductor rectifier circuit.The experimental results show that: the classical rectifier circuit components consume about 33.73% of the output power of the energy collector,the output power of the BST cantilever structure load in the synchronous charge extraction circuit is about 2.69 nw,which is about 1.72 times of the classical rectifier circuit state of 1.562 nw and the output power of the BST cantilever structure load in the parallel synchronous switched inductor rectifier circuit is about 5.56 nw,it is about 3.56 times of the state of the classical rectifier circuit.In the multi-source out of phase synchronous switch rectifier circuit,the output power of the energy collector is not affected by the phase difference of each energy converter,which avoids the mutual cancellation of the AC energy generated by the energy collector and ensures the work efficiency of the multi-source out of phase energy collection system.Finally,summarize the research work of this paper,put forward the energy harvester structure,circuit design guidelines and propose parameter optimization design schemes.