Power flow control and regulation circuits for magnetic energy harvesters

This paper presents control schemes for power flow and voltage regulation for magnetic energy harvesters, using unique operating properties set by a current-driven harvester core. An active rectification circuit and a voltage regulation circuit are introduced based on assumptions of a supercapacitor and a MHz microcontroller that is already accompanied in the sensor node. Detailed analyses on circuits, control methods, and state transitions are provided from an implementational viewpoint. In the experiment, fine regulation of 48mV is achieved at the nominal voltage of 4.5 V with increased power dissipation in μW range, and the active rectification method boosts power harvest by more than 10% compared to a conventional full-bridge diode rectifier. An overall architecture of the power processing circuits are first introduced, and circuit and control analyses are proposed. Simulation and experimental verification subsequently follow to demonstrate effectiveness of the proposed circuits and control methods.