Energy Harvesting circuit for Digitization of Wiegand Pulse using Buck Converter in Discontinuous Conduction Mode

Energy harvesting using Wiegand sensor as self-sustaining sensor is an emerging research area. The Wiegand sensor is a magnetic sensor that relies on the phenomenon of large Barkhausen jumps, generates a triangular voltage pulse upon the application of an alternating magnetic field. Pulse generation occurs regardless of how slowly the magnetic field variation occurs, is an attractive feature which enables its use as an energy harvester even in presence of low-frequency sources. Wiegand sensor as a sensing element have been used in many applications. But Wiegand sensor as energy harvester opens interesting, yet still overlooked possibilities in the energy harvesting field. The major challenge with the Wiegand sensor is energy harvested per pulse in the range of nJ. In this research work, we have proposed the circuit using Wiegand sensor that uses buck converter in discontinuous mode (DCM) mode to generate the digital pulse of 4.5 V and 10 ms at extremely low frequency for each magnetic field reversal without the use of any external power supply. Battery-less digital pulse generation is demonstrated for rotating application in the present study. The operating frequency up to 100 Hz has been considered. The main advantage of the proposed circuit is digitization of triangular shape Wiegand pulse is feasible for extremely slow varying magnetic field which can be used directly by microcontroller unit for further analysis.