Self-Powered Synchronous Electric Charge Extraction Rectifier for Rotational Electret Energy Harvester With Dual-Stage Electrodes

This article presents for the first time the development of a self-powered synchronous electric charge extraction (SECE) circuit for an in-plane rotational electret kinetic energy harvester (EH) with a cold start function. As an electret EH features low source current and high output impedance, its output power is sensitive to the leakage current and the parasitic capacitance. A novel dual-stage electrode design is proposed, with the control stage providing a sub-5V supply to the control circuit and triggering a synchronous switch in the high-voltage main circuit. Compared to a conventional buck converter, the power harvested on a 5-V load was doubled with the present synchronous electric charge extraction (SECE) prototype. Based on the circuit simulations, the achievable power increase at the generator output with the proposed circuit is mainly constrained by the impedance introduced by itself. The experimental results show that the circuit can be cold-started and directly powered by electret EHs.