Mathematical Model And Experimental Verification Of Impact-Based Piezoelectric Vibration Energy Harvesters

The impact-based vibration energy harvester can efficiently collect broadband and low-frequency vibration energy in the environment,and has a broad application in wireless sensor and other fields.However,the researches on the theory and design methods of impact-based vibration harvester are not further enough to provide a sufficient theoretical support for the development of high-performance impact-based vibration energy harvester.It is of great significance to carry out the research on related theory and the design methods of impact-based piezoelectric vibration energy harvester.Based on the previous research of our group,the Mathematical model of the impact-based piezoelectric vibration energy harvester was improved in a further degree,and a more general optimization of the load calculation was derived,and a corresponding numerical simulation program was developed,and the optimizations were proposed and verified by experiment.The results of the thesis have certain guiding significance for the optimal design of impact-based vibration energy harvester.The main work includes:(1)The advance in impact-based piezoelectric vibration energy harvester especially in the theoretical models field was analyzed and summarized.(2)Based on the previous research,the mathematical model of the vibration energy harvester with a rolling mass was deduced.And the analytical expression of the output voltage after impact was deduced.On this basis,a simpler calculation method for optimizing load resistance for impact-based piezoelectric vibration energy harvester was established.This method is more universal.(3)The response of the harvester was simulate by MATLAB software,the influence of the load,excitation frequency,acceleration amplitude and impact point on the output were analyzed.It is found that when the foundation excitation is large,the frequency response curve of the output power is fluctuating,and the reasons for this phenomenon are preliminarily analyzed.The harvester has a higher output power when selecting the appropriate impact point which makes ratio value of the equivalent mass of the cantilever beam and the quality of the ball is large.(4)The harvester prototype was tested.The electromechanical coupling model was verified by parameter identification.The influence on load,frequency,acceleration amplitude and impact point on the electrical output of the harvester was experimentally analyzed.It shows the same trend between the numerical analysis and experiment.When the acceleration amplitude is 0.7g,the impact point location is 9.5mm,the frequency is 11.7Hz,and the load resistance is 17k?,the maximum output power of a single piezoelectric cantilever beam is about 255.5?W.