Magnetic Field Energy Harvesting From Current-Carrying Structures: Electromagnetic-Circuit Coupled Model, Validation and Application

Yang Kuang,Meiling Zhu,Tingwen Ruan,Zheng Jun Chew

doi:10.1109/access.2021.3068472

Yang Kuang, Meiling Zhu + Show 2 more

Open Access

https://doi.org/10.1109/access.2021.3068472

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Abstract

Magnetic field energy harvesters (MFEHs) from current-carrying structures/conductors are usually modelled as decoupled electromagnetic and electrical systems. The current-carrying structures may affect the performance of MFEH through the generation of the eddy current and the alteration of the magnetic reluctance. Moreover, the load circuit affects the current generated in the coil and therefore the flux density and eddy current generated. The effects of the current-carrying structure and the load circuit cannot be fully described by the decoupled models. This work develops a finite element model (FEM) that fully couples the electromagnetic and electrical systems by simulating both the magnetic field and eddy current distribution of an MFEH connected to an electrical circuit. The FEM first simulates the coil inductance and resistance of a magnetic field energy harvester (MFEH) placed close to a current-carrying structure exemplified by a rail track. The FEM then simulates the outputs of the MFEH connected to an electrical circuit consisting of a compensating capacitor and optimal load resistor determined by the first step. An MFEH was fabricated and tested under a section of current-carrying rail track. Both experiment and simulation show an increase of both coil resistance and inductance when the MFEH is placed close to the rail track. The good agreement between experimental and simulation results validates that the FEM can predict the full-matrix performances of the MFEH, including the coil parameters, power output and magnetic flux density under the influence of the current-carrying structure and the load circuit. Simulation results reveal that in addition to the permeability of the magnetic core, the electrical conductivity and magnetic permeability of the current-carrying structure considerably affect the performance of the MFEH, which cannot be predicted by decoupled models.

Highlights

Condition monitoring of critical assets is crucial to enhance the management and maintenance for increased capacity and efficiency
The simulation results are in good agreement with the experiment. dc = ∞ means the coil parameters were measured or simulated without the presence of the rail track
The Coil-parameter study of the finite element model (FEM) was developed in the ‘Magnetic and Electric Interface’ (MEI) of COMSOL, which is capable of computing the magnetic field and eddy current distribution

Summary

Introduction

Condition monitoring of critical assets (e.g. overhead power lines and railway) is crucial to enhance the management and maintenance for increased capacity and efficiency. This usually involves a great number of sensors distributed in a large geographic area to monitor and report the status of the assets [1]. Wireless sensors are powered by batteries, which have a limited energy capacity and lifetime. Once depleted, these batteries need replacement or recharging. The replacement or recharging of batteries can be difficult when the wireless sensors are in great number and/or distributed in a large geographic area. An alternative power source to batteries is energy harvesting (EH), which converts ambient energy to useful electricity to supply wireless sensors [3]

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