Hybrid energy harvesting for self-powered rotor condition monitoring using maximal utilization strategy in structural space and operation process

The energy harvesting technology is capable of harnessing the intrinsic rotating energy of the rotor system to realize self-powered rotor condition monitoring for the Internet of Things (IoT). It is promising to solve the issue of sustainable energy supply of the rotor monitoring system and achieve a self-powered IoT. In this work, we propose a novel maximal utilization strategy for piezoelectric-electromagnetic-triboelectric energy harvesting in a broad speed range and achieve the self-powered rotor condition monitoring system. The piezoelectric energy harvester (PEH), triboelectric nanogenerator (TENG), and electromagnetic energy harvester (EMH) are respectively arranged in the place where the system exhibits the maximum strain, the maximum contact area, and the maximum displacement, respectively, which can make full use of their characteristics in the structural space. The modulation boundaries (parts of TENG) render a more controllable dynamic behavior of the harvester, and realize the vibration and impact coordinated power generation mode, which can harvest more mechanical energy in the time domain. The theoretical mathematical model and working criteria of the proposed system are established and verified experimentally. In addition, the prototype can operate effectively in a wide speed range (0–1000 r/min) and it can charge a 100 μF capacitor to 5 V within 11 s. The self-powered rotor wireless temperature monitoring and self-powered wireless tire pressure monitoring are realized during the practical road tests. The maximum utilization strategy provides a new design methodology for hybrid energy harvesting, which has potential applications in intelligent driving and rotating machinery condition monitoring.