Research On Low Frequency Vibration Power Generation System Based On Piezoelectric Ceramics

Piezoelectric ceramics have a good piezoelectric effect,and vibration phenomena can be seen everywhere.Using the piezoelectric effect of piezoelectric ceramics to convert environmental vibration energy into electrical energy is undoubtedly of great significance for the development of green energy.At present,one of the main reasons restricting the development of this technology is that the resonance frequency of the piezoelectric energy harvester developed is higher than the vibration frequency of the environment,and the energy harvesting frequency band is narrow,resulting in low energy conversion efficiency of the piezoelectric power generation system,which is difficult to meet the requirements.Demand for electrical equipment.Aiming at this problem,this paper combines the linear multi-degree-of-freedom theory with the bistable method,and proposes a three-degree-of-freedom bistable energy capture method.This method amplifies the excitation amplitude acting on the cantilever beam,reduces the resonance frequency of the energy trap,effectively broadens the energy trapping frequency band of the energy trap,and greatly improves the energy conversion efficiency of the piezoelectric power generation system.This article mainly carried out the following research work:(1)The internal relationship between the structure of the piezoelectric ceramic cantilever beam and its resonance frequency is studied.The structure of the piezoelectric ceramic cantilever beam is optimized by the method of dynamic modeling,and the linear piezoelectric ceramic cantilever beam is analyzed by finite element software.Existing problems and their reasons,the principle of bistable power generation is studied,and the existing problems of the current bistable system are analyzed using finite element software.(2)Aiming at the problems of the bistable system,combining the linear three-degree-of-freedom theory with the bistable method,a three-degree-of-freedom bistable power generation method is proposed: theoretically analyzes the three-degree-of-freedom cantilever beam Natural frequency;the physical model of the three-degree-of-freedom bistable power generation method is constructed;the natural frequency of the three-degree-of-freedom bistable power generation model is simulated;the contribution of the magnetic force to the energy capture in the model is analyzed;the output characteristics of the model are analyzed.(3)Based on the proposed method,a three-degree-of-freedom bistable power generation device is designed,and a prototype is produced.Through the actual measurement and analysis of the prototype,it is proved that the three-degree-of-freedom bistable power generation method proposed in this paper can effectively reduce the piezoelectricity.The resonance frequency of the ceramic cantilever beam broadens the energy trapping frequency band of the piezoelectric ceramic cantilever beam to a large extent;it also proves that the three-degree-of-freedom bistable power generation method proposed in this paper can greatly improve the energy conversion efficiency of the system.(4)The output of the three-degree-of-freedom bistable power generator based on piezoelectric ceramics is an unstable AC voltage,while the electrical equipment requires a stable DC voltage.To this end,an energy harvesting circuit and an electrical energy storage circuit are designed.After simulation verification,the output voltage of the designed circuit can meet the needs of electrical equipment,and the electrical energy output by the power generation device can be stored when the equipment is not powered.