Design and Verification of a Rail-Borne Energy Harvester for Powering Wireless Sensor Networks in the Railway Industry

Design, modeling, simulation, and vibration testing related to electromagnetic energy harvesters are investigated in this paper. A rail-borne electromagnetic energy harvester with copper-beads spacing is proposed and fabricated, the suitable for harvesting vibration-induced energy of the wheelset/track system. A vehicle-track model considering vehicle traveling load is constructed and numerically solved by fast explicit integration methods. An electromagnetic model is established to predict the induced voltage. The track irregularity power spectrum density is applied as excitation source on the track. Based on the calculation results, both the resonant harvester and the magnetic levitation harvester are designed. The solution utilizes copper beads as radial spacing, which guarantees reliable unidirectionalmovement of magnets inside a multilayer-multirow coil. Vibration tests are conducted with the proposed track-borne device, and a hydraulic driven system is exploited to generate the realistic wheelset/rail interaction force. The proposed railborne energy harvester can be mounted to the track easily and extensively. The magnetic levitation harvester offers an approach for harvesting broadband low-frequency (3-7Hz) wheelset/track interaction with the rail displacement of 0.6 to 1.2 mm. For the resonant harvester, the output power of 119 mW and the output peak-peak voltage of 2.32 V are achieved with the rail displacement of 1.2 mm, the coil height of 48 mm, the load resistance of 45 Omega, the coil inductance of 105.572 mH, and 3000 numbers of turns. Furthermore, a dc-dc boost converter is proposed, which is capable of converting the alternating voltage of the transducer into 5 V/10-mA dc output at the resonant frequency of 6 Hz, the rail displacement of 2 mm, and the induced voltage of 3.4 V.