PSPICE-Based Analyses of the Vibration Energy Harvester System With Multiple Piezoelectric Units

It has been a challenge to determine the optimal energy-storage capacitance in piezoelectric vibration energy harvesting (VEH) systems for a given working time. In this paper, the PSPICE software is used to determine the optimal energy-storage capacitance in a VEH system with one or more piezoelectric modules, for maximizing the energy harvesting capability, and to investigate the dependence of this optimum energy-storage capacitance on the device and working parameters. The simulation method is verified by experimental results. It is found that the optimal energy-storage capacitance increases with an increase of the clamped capacitance, working frequency, and working time of the piezoelectric modules. It is also found that the optimal energy-storage capacitance is proportional to the number of the piezoelectric modules used in the VEH system if the piezoelectric modules have close parameters.