Magnetic Field Energy Harvesting in Railway

Abstract

Magnetic field energy harvesting (MFEH) is a method by which a system can harness an ambient, alternating magnetic field in order to scavenge energy. Presented in this article is a novel application of the concept aimed at the magnetic fields surrounding the rail current in electrified railway. Due to its noninvasive nature, the approach has the potential to be widely deployed as a part of low-cost trackside condition monitoring systems in order to increase lifetime and reduce maintenance requirements. In this article, the viability of MFEH in railway is substantiated experimentally—two different configurations are assessed both in a controlled laboratory environment as well as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> along Norwegian railway. When placed near an emulated section of railway carrying 200 A in the laboratory, the power output of the system is up to 40.5 mW at 50 Hz and 4.15 mW at 16 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\frac{2}{3}\; \mathrm{Hz}$</tex-math></inline-formula> . In the field, the prototype system harvests 109 mJ from a single freight train passing by, rendering an estimated daily energy output of 1.14 J in a moderately trafficked location. It is argued that the approach could indeed eliminate the need for battery replacements and potentially increase the lifetime of an energy-efficient, battery-powered condition monitoring system indefinitely.