Enhancement of Digital Self-Powered Energy-Harvesting for 2DOF Mixed-Mode Vibrations

The digital self-powered energy harvesting method that we propose is a switching-type vibration energy harvesting method that has a circuit that is functionally integrated with a digital processor. The main feature of the proposed harvester is that the digital processor is driven by energy harvested from vibration. Therefore, other electrical power sources, such as batteries, are not required to power it. The self-powered digital processor automatically changes the states of the harvester circuit using a switching control method. The switching is synchronized with the vibration phase, which is conducive to the effective conversion of vibrational energy. The proposed harvester is programmable and easily implements different types of control schemes based on its various parameters. This study has two objectives regarding the digital self-powered harvesting method. The first objective is to evaluate the power generation performance of the self-powered harvester for multimodal vibrations. Several experiments employing an experimental apparatus with two degrees of freedom (2DOF) are conducted. The second objective is to apply a new switch control scheme to our proposed harvesting method. The scheme is designed for moderate energy harvesting: it intentionally pauses the harvesting action so as to increase the amount of energy generated later. This method is different from the former method of switch control. We confirm the usability of the new control scheme in a digital self-powered system.