Research On A Magnetic Coupling Piezoelectric Vibratory Energy Harvester

Using of piezoelectric vibratory energy harvester to provide energy for micropower electronic products and miniature remote sensing monitoring systems, which has become a research focus in many fields. The local oscillator frequency is usually lower within real environment and the piezoelectric vibratory energy harvester itself fundamental frequency usually higher, lumping mass at the end of piezoelectric vibratory energy harvester would cause damage to it. In order to meet the fundamental frequency of the piezoelectric vibratory energy harvester adapt to environmental vibratory frequency achieve high energy harvesting generating. The paper proposes to use the method of the magnetic coupling effect to construct izod piezoelectric vibratory energy harvester, and theoretical and experiments will be implemented to study, hence get the energy harvesting characteristics and influencing factors the of harvester within different modes of magnetic coupling (magnet configuration and its biasing force forms). Specific researches as follows:1. The piezoelectric cantilever is one of the most important element of piezoelectric vibratory energy harvester, whose performance exerts great influence on the energy harvesting ability of piezoelectric vibratory energy harvester. According to the piezoelectric theory and mechanics of materials theory, build theoretical model of the single crystal and double crystal piezoelectric cantilever electromechanical energy conversion and numerical simulation analysis, where two different external incentives for constant force and constant displacement amount. Specific study open-circuit voltage and energy harvesting with the influence rules of the thickness of the metal substrate, the thickness of the piezoelectric sheet and the ratio of thickness when three different sizes of the piezoelectric cantilever include the the thickness of the piezoelectric sheet, the thickness of the metal substrate and the total thickness of the piezoelectric cantilever remain unchanged, which provide a theoretical reference for the analysis of energy harvesting performance of the piezoelectric cantilever.2. Established a theoretical model of the magnetic coupling piezoelectric vibratory energy harvester, and study the influence relationship between the magnetic rigidity and the forms of magnetic force between magnets. Solve approximate solution of the steady-state response and phase difference with the magnetic coupling piezoelectric vibratory energy harvester, which make use of harmonic balance method within quantitative analysis method. Analysis of the amplitude-frequency phase-frequency characteristic of the magnetic coupling piezoelectric vibratory energy harvester, study the open-circuit voltage characteristics importantly, hence get the relationship between the the optimum operating frequency of magnetic coupling piezoelectric vibratory energy harvester and the way of magnetic coupling:The optimum operating frequency of magnetic coupling piezoelectric vibratory energy harvester would be tuned down as the form of magnetic force is repulsive, the optimum operating frequency would be tuned up as attractive.3. Constructed ten kinds of structure of the magnetic coupling piezoelectric vibratory’ energy harvester within three categories.which used the same one piezoelectric cantilever and the same model of permanent magnets. Such as single magnet vertical coupling.dual magnets symmetrical vertical coupling and single magnet level horizontal coupling,acting force for the repulsive/attractive, dual magnets repulsive/attractive simultaneously and the dual magnets repulsive and attractive combined. And maked the performance testing and comparative analysis of piezoelectric vibratory energy harvester within different magnetic forces (initial distance between magnets), respectively. The results show that the output voltage and optimum operating frequency of magnetic coupling piezoelectric vibratory energy harvester is not quite similar within different modes of magnetic force:The combined effect mode of magnetic coupling (repulsive or attractive) change the optimum operating frequency (down or up), and the equivalent spring effect of magnetic rigidity change the maximum voltage (decreased or increased), which consistent with the theoretical analysis. Hence we can choice suitable modes of magnetic coupling as different using purposes depending on the applications.