Design, modelling and field test of a track-borne magnetic field energy harvester for electrified railways

Magnetic field energy, which is abundant in electrified railways, can be harnessed to power condition-monitoring sensors distributed along rail infrastructures. Despite its potential, this energy source has received little attention. This paper proposes a track-borne magnetic field energy harvester (MFEH) designed to scavenge the magnetic field energy generated by traction-returning current conducted in rail tracks. The MFEH, featuring a low-profile magnetic core made of laminated silicon steel, is designed for reliability in the harsh railway environment and for simplicity in manufacturing, packaging, and installation. Finite element analysis and lab tests were conducted to characterize its performance under the influence of eddy current generation and nonlinear magnetization. Field tests at a high-speed railway were performed to evaluate the MFEH's performance in real-world settings. Lab tests indicate that the MFEH can generate an average power of 184 to 5178 mW when the current conducting in the track varies from 100 to 500 A. Field tests show that the passing of each high-speed train generates a burst of magnetic field up to 43 ± 29 μT, suggesting a current up to 109 ± 73 A conducting in the rail track. This results in a power output of up to 670 ± 837 mW and an energy output of 1138 ± 1603 mJ from the MFEH as each train passes. This energy output enables the MFEH to power a wide range of wireless sensors, offering a promising future for rail infrastructure health monitoring.