Magnetic Field Energy Harvesting with Broad Frequency Band

Magnetic fields with a broad frequency band are widely distributed in the nearby space of power electronic devices. Harvesting magnetic field energy over these frequency bands will help supply wireless devices. This paper proposes a method of harvesting magnetic field energy from broad frequency band over k-Hz. Two broadband impedance matching networks based on Butterworth design and optimal power bandwidth product design are proposed, which have the characteristics of flattest power pass and maximum power pass, respectively. The designed prototype can harvest magnetic field energy in a broad frequency band from 10 kHz to 20 kHz. With eleven frequency points selected from magnetic field strength measurement in an MMC valve hall, total power of 410 μW for Butterworth matching network and 460 μW for optimal PBP matching network can be obtained.