Simulation of an energy harvesting system with broadband excitation

For sinusoidal vibrations, it is known that energy harvester power output can be improved by employing switching power conversion circuitry that controls the load cycle of the transducer. We have investigated by numerical simulation how such a power conversion technique performs for a piezoelectric harvester when the vibration is not sinusoidal but has random character and a bandwidth much larger than that of the harvester. We also include the effect of mechanical stoppers. The results are compared to those for a purely resistive load. Our main findings are that the switching conversion circuitry performs better, especially when stoppers are in effect, and that stopper loss is important under broadband vibrations in contrast to sinusoidal vibrations.