Research On A Hybrid Broadband Piezoelectric-electromagnetic Energy Harvesting Technology

In recent years, electronics, communications, and other products have considerableprogress in the development of being portable and wireless. And various short and thinelectronic products have appeared, but the lag of micro energy technology hindered thedevelopment of a variety of high-performance components, and therefore the demand ofmicro energy that has high energy density, small size, light weight is very urgent.Ambient vibration energy is ubiquitous energy, and the micro vibration generatortransforming the vibration energy into electrical energy has attracted wide attention. Theresearchers have proposed a lot of optimization methods to make the harvester gain abetter output performance, including optimization of the circuit and the mechanicalstructure parameters. Because the electromechanical coupling coefficient of thepiezoelectric and electromagnetic generator is high, and it does not require an externalpower supply, some researchers proposed a kind of piezoelectric-electromagnetichybrid energy harvester.This paper proposes a new piezoelectric-electromagnetic energy harvestingstructure and analyze it from the perspective of numerical analysis, simulation andexperimental study. The results were as follows:Firstly, a mathematical model of hybrid energy harvester was established to obtainthe output power of the single piezoelectric, electromagnetic and hybrid energyharvester, respectively. Then MATLAB was used to do the numerical analysis,considering the effect of load resistance and structural parameters on the output powerof the harvester. Numerical results show that the optimal load resistance exists in singleenergy harvesting system, and the power output of the energy harvester can beimproved by optimizing the structure parameters. The output power of the hybridenergy harvester is higher than that of a single energy harvester, and the bandwidth iswidened.Secondly, the output performances of the single and hybrid energy harvester werestudied in ANSYS and Maxwell. Simulation results show that the structural parametersand external resistor have a great influence upon the output power, and the hybridenergy harvester has a higher output power and a wider bandwidth.Finally, an experimental system was built and the research was carried consideringthe influence of the external resistor, the distance between magnets as well as theacceleration upon the output power of the harvester. Then the experiment of the hybridenergy harvester was carried on the condition that the external loads were optimal. Thepower outputs of the hybrid energy harvester from18Hz to30Hz are ideal. The comparison of numerical analysis, simulation analysis and experiment results showsthat the error is small, and that verifies the correctness of the analysis.