Self-Propelled Pre-Biased Synchronous Charge Extraction Circuit for Triboelectric Nanogenerator

Triboelectric nanogenerators (TENGs) are suitable for harvesting ambient mechanical energy to increase the battery life of the Internet of Things (IoT) devices. Energy extraction circuits (EECs) are required as an interface between TENG and the onboard battery load to rectify and improve the energy transfer efficiency. Here, for the first time, a novel “self-propelled pre-biased synchronous charge extraction (spSCE)” EEC is presented with theoretical analysis as well as experimental results. The proposed EEC offers a universal plug-and-play solution for any TENG operating under any ambient vibration, due to its self-propelled switching feature. In addition, its inbuilt pre-biasing (precharging of TENG capacitor at the operation extremes) action enhances the net transduced energy from the mechanical source beyond the per-cycle energy limit for any non-pre-biasing EEC set by the existing synchronous charge extraction (SCE) circuit. Accounting for the energy costs of spSCE actions, our experiments validated 119.7% (resp., 163.7%) energy gain over the SCE circuit at a load of 5 V (resp., 15 V).