Investigation on a broadband magnetic levitation energy harvester for railway scenarios

In this study, a Magnetic Levitation Energy Harvester (MLEH) was designed and fabricated. The magnetic field distribution and power generation performance of multiple cylindrical magnets were studied. The full factorial design (FFD) of L₂₀ (2² × 5) test was carried out with the sliding magnet arrangement, coil arrangement and wiring method as the control factors, and the output power as target factor. Sweeping-frequency vibration tests and railroad spectrum random vibration tests were conducted to verify the power generation capacity of the prototype. Experimental results show that the device has a broadband response and the railroad vibration test proves the effectiveness of harvester in the application scenario for powering the rail-side sensors. The range of maximum output voltage, power and corresponding frequency in sweeping-frequency vibration tests with the amplitude of 1 to 10 mm and frequency of 5 to 50 Hz are 1.5 to 4.5 V; 1.80 to 17.0 mW and 9.7 to 30.8 Hz. The maximum output voltage and power are 1.33 V and 1.47 mW based on the measured railroad spectrum. Finally, a retrospective review in the efficiency, effectiveness and volume figure of merit is conducted to evaluate the performance of MLEH, indicating a high power density of the proposed harvester.