Free‐Fixed Rotational Triboelectric Nanogenerator for Self‐Powered Real‐Time Wheel Monitoring

Abstract Developing an applicable triboelectric nanogenerator (TENG) for train wheel energy harvesting is a key step to meet the urgent need of wheel safety monitoring. Herein, an innovative design of free‐fixed TENG (FF‐TENG) is reported, without a serious negative impact on the wheel. The key of this design is the magnets fixed on the device and bogie, providing attractive force to immobilize the stator. With a rotational structure, FF‐TENG can provide a high short‐circuit current of 55 µA, an open‐circuit voltage of 500 V, and a charge of 235 nC at a rotation speed of 400 rpm. At an external load resistance of 10 MΩ, FF‐TENG delivers the maximum power of 15.68 mW. Furthermore, the superior robustness of FF‐TENG in vibration environment is proved. In addition, a power management circuit designed by LTC 3588 is tested for more efficient capacitor charging, leading to better performance to power electronics. Finally, a self‐powered real‐time wheel temperature and wheel speed monitoring system is developed with FF‐TENG as a safety alert demo for feasibility demonstration. Given the rational structure design and high performance, this work paves a practical way for TENGs in the field of intelligent transportation.