Research On Energy Conversion Technology Of Air-induced Acoustic Piezoelectric Generator

According to the piezoelectric effect,airflow induced acoustic piezoelectric generator has the characteristics of simple structure,small volume and high energy.It is a new type of physical power source for environmental protection and renewable fuze.Based on acoustic excitation vibration source technologies,the study of energy acquisition and storage technology in this paper is further carried out.Passive synchronous switch control acquisition and storage circuit are designed.Through the system analysis and experimental verification,the prototype is completed and providing a technical support for the next step of product.By analysising the research results of piezoelectric generator's structure and energy harvesting circuit both domestic and overseas,the purpose of the study is clearly confirmed.Mainly through raising load receive power and reducing consumption of the interface circuit power,emphatic research the key technologies of energy harvest and storage.The excitation theory of hydrodynamic sound source induced by external airflow is analyzed.The internal airflow field and acoustic characteristics at the inlet and nozzle-resonator structures are respectively described.Pointed out that the output alternating current of this piezoelectric generator is stable.A pulse excitation synchronous acquisition method for piezoelectric generator is proposed.By simulating the Synchronous Charge Extraction(SCE)circuit,Parallel-Synchronized Switch Harvesting on Inductor(P-SSHI)circuit,Series-Synchronized Switch Harvesting on Inductor(S-SSHI)circuit,analysis the effect of load resistance on transducer's output voltage and load receive power.Finally comes to the conclusions:external SCE circuit,piezoelectric generator can increase the output voltage,but the load receive power is stable;external S-SSHI circuit,suitable for matching lower load condition;external P-SSHI circuit,suitable for matching higher load condition.The generator's charge synchronous acquisition and control technology is reserached.Two kinds of switch control circuits,Improved S-SSHI and Improved P-SSHI are designed.The maximum load receive power of the two switch control techniques are higher than 40mW,which is more than 4 times of the Stand Energy Harvesting(SEH)circuit.The Improved S-SSHI technique has the characteristics of fastest respond and stable output voltage,satisfied the requirements of fuze.The energy storage control method is designed.According to the characteristics of capacitance value affect the voltage responding stabilization time and load voltage waveform,but not affect the stability value of load voltage.An electronic speed control switch is designed to adapt the voltage response of different energy storage capacitors.The simulation results show that the larger the capacitance is,the smaller the waveform error is,and the longer the responding stabilization time is.The users can choose the switch according to their requirements.Finally,build an air compressor blower test platform,then analyzing the test signal.The results show that frequency of the generator's output voltage signal keep pace with frequency of the excitation sound pressure signal,meets the theoretical deduction results;Piezoelectric generator's output voltage and load receive power are in line with the simulation results.