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.