Flipped Capacitor Based Energy Harvester for Triboelectric Nanogenerators

Abstract

A main drawback of triboelectric generators is the large open circuit voltage that they may produce. A capacitor was connected in parallel with the TriboElectric NanoGenerator (TENG) to reduce the voltage down to a desired value and to force the TENG to have a similar model than a piezoelectric generator (PZG), while reducing the effect of the variable capacitance of the TENG. The Synchronized Switch Harvesting on Capacitor (SSHC) method, originally proposed for piezoelectric generators, was adapted for this application. The proposed flipping algorithm determines the switching instants based on the voltage levels of the capacitors, rather than on fixed times, achieving a charge efficiency of 50% with one flipping capacitor; thus, increasing the amount of harvested energy. Simulation results show the feasibility of the proposed energy harvester, showing that in this example 140% more power can be transferred to the load.