Core Material Evaluation for Magnetic Energy Harvester Applications

Abstract

Current transformer magnetic energy harvesters (CTMEHs) harvest magnetic energy from an AC current-carrying conductor and convert this energy into usable electrical energy for use by various low-power devices, such as sensors and microcontrollers. The amount of power harvested by CTMEHs is determined by the primary current passing through the conductor; however, variables such as the magnetic core’s dimensions, magnetic properties, and turn count also influence performance. Previous works have focused mainly on analytical or numerical modeling of CTMEH behavior or improving power harvest performance given a specific magnetic core material. Some existing research has compared the effects of different core materials on CTMEH power harvest in limited fashion; but a comprehensive, comparative study of high permeability, high saturation flux density CTMEHs had yet to be explored. This thesis establishes core material as the primary independent variable along with primary current and frequency during testing to isolate the effects of magnetic properties on determining the amount of power a magnetic core can harvest under different current conditions. The thesis concludes that nanocrystalline material excels at lower-current applications, while silicon steel material offers better performance at higher-current applications across all frequencies when used as CTMEHs, offering system designers enticing material choices depending on the nature of the application.