| With the rapid development of micro electro mechanical system(MEMS)technology,the wireless sensor network with the advantages of low cost,small size,multi-function has become a hot spot in the world.However,the hysteresis energy supply technology of MEMS restricts the development of wireless sensor network.Therefore,make the MEMS self powered device through the environmental energy harvesting system,has aroused the concern of many scholars.The vibration energy in the environment has the advantages of high energy density,wide distribution,stable energy supply and so on,and the piezoelectric and electromagnetic energy harvesting is more suitable for vibration energy harvesting,therefore,the use of piezoelectric and electromagnetic energy conversion mechanism to transform the vibration energy into electrical energy has become a research hotspot.However,the existing research in the energy harvesting system only has a narrow range of frequency response,and low energy conversion efficiency,which seriously restrict the vibration energy harvesting device can be practical.Therefore,the study of a broadband and high efficient energy harvesting vibration has important theoretical value and practical significance of device.This paper presents hybrid piezoelectric electromagnetic energy harvesting system based on a multi-mode spiral cantilever structure,and research on the power in three aspects from the theoretical analysis,simulation analysis and experimental research.The results are as follows:First of all,build a composite piezoelectric dynamic modeling system based on the lumped parameter model,using Castigliano’s theorem modifies the lumped parameter model.Composite power generation performance modeling and solving system of energy harvesting based on dynamic model,get the amplitude frequency characteristics of multi-mode hybrid piezoelectric electromagnetic energy harvesting system output power.The theoretical analysis shows that the composite piezoelectric output characteristics of discrete system with broadband.Secondly,using the finite element analysis software ANSYS workbench and Ansoft Maxwell on the multi-mode piezoelectric composite electromagnetic energy harvesting system is simulated by finite element analysis,get the power generation performance ofpiezoelectric composite system under the condition of a single piezoelectric,electromagnetic and piezoelectric single hybrid piezoelectric electromagnetic energy harvesting power.By analyzing the simulation results,multi modal spiral structure to broaden the output frequency band,composite energy harvesting improves the energy harvesting efficiency,and the existence of a composite piezoelectric coupling system weaken each other.Thirdly,analysis the existing energy recovery interface circuit,then through the analysis of output characteristics of multi-mode piezoelectric composite electromagnetic energy harvesting system,design a multi energy collection circuit and conditioning and storage strategy for multi-mode hybrid piezoelectric electromagnetic energy harvesting system.Finally,this paper built a multi-mode hybrid piezoelectric electromagnetic energy harvesting system experimental platform,and carries on the single piezoelectric and composite piezoelectric power generation performance experiment,the experimental results show that the output power of the multi-modal piezoelectric-electromagnetic composite capture device is relatively high near the resonant points of 26 Hz,42Hz,50 Hz,88Hz and100 Hz,under the first two modes,the output power of multi-mode piezoelectric composite electromagnetic energy harvesting system can be improved by 8.6% and 2.8%,respectively,compared with that of single piezoelectric energy harvesting system.It is proved that the multi-mode hybrid piezoelectric electromagnetic energy harvesting system has the advantages of wide frequency and high efficiency.And the results of theoretical analysis and simulation analysis and experimental analysis are highly consistent,the experimental results verify the correctness of numerical analysis and simulation analysis. |
