A Study On The Energy Harvesting System Based On A Synchronized Nonlinear Switching Technique

In recent years, the field of energy harvesting has been expanded its space more and more and this mainly attribute to the advancement in wireless systems and low power electronics devices. When energy harvesting technology is combined with the low power electronic devices, their application field could be greatly enlarged.Because of its outstanding property of electromechanical coupling, the piezoelectric materials which are considered as a traditional function materials, have absolute advantages in the application of modern electro-mechanical system. In this study, a energy harvesting system on vibrational energy was built by attaching piezoelectric patches to the root of a cantilever beam, further more, a technology of using synchronized nonlinear switching in this energy harvesting system was proposed and validated that could greatly enhance the power efficiency of the system.In chapter 3 of this thesis, the theoretical analyses were studied and the energy harvesting with synchronized nonlinear switching were theoretically discussed in great details. Also, a new method that combines a voltage multiplier and synchronized nonlinear switching in energy harvesting system was proposed. This new method, which enables the negative electrodes of piezoelectric patch,the analog and numeric ground of the control circuit and energy storage components such as rechargeable batteries or super capacitors be grounded at the same time compatibly, this new feature indicates that the hole system could be directly supplied with the harvested power.In chapter 4 of this thesis, the global simulations of the 4 different systems were performed with orcad/pspice. The simulation was based on the electric model of piezoelectric patch and some models of low power electronic components. The simulation results were in good agreement with the theoretical calculations, while only the results of synchronous charge extraction method was a little lower when compared with theoretical results. In chapter 5, the test on the 4 different energy harvesting system was performed using dspace control board. The output of these systems versus different resistive loads were measured, the measured parameters were in good agreement with that of simulations. Finally, an integrated circuit was designed and manufactured to modularize the whole system.The last chapter summarizes the current work and makes suggestions for future work.