Dual-Rotor-Structured Triboelectric-Electromagnetic Hybrid Generator for Shaft System Rotational Energy Harvesting and Self-Powered Sensing

The monitoring of ship propulsion equipment requires sensors that are intelligent, miniaturized, and low-power. However, traditional wired and battery-based power supplies restrict the reliable deployment and long-term operation of these sensors. This paper proposes a high-power triboelectric-electromagnetic rotational energy harvester adapted for low-speed conditions. The device uses a double-rotor structure to simultaneously increase the axial triboelectric area and enhance the magnetic flux density, improving the energy conversion efficiency of both the triboelectric nanogenerator (TENG) and the electromagnetic generator (EMG). The system includes two TENGs and one EMG sharing a rotor architecture for different operation modes. Experimental comparisons show that connecting TENGs in parallel yields a better electrical output than series connections. At 150 rpm, the TENG delivers a peak open-circuit voltage of 487.02 V, a short-circuit current of 13.10 μA, and a peak power of 6.11 mW under impedance matching, while its power density is 4.03 W·m–3, compared to 350.42 W·m–3 for the EMG under the same conditions. At 300 rpm, the TENG and EMG achieve peak open-circuit voltages of 850.72 and 51.06 V, and peak short-circuit currents of 22.1 μA and 396.3 mA, respectively. This integrated system, combining triboelectric and electromagnetic energy harvesting, successfully provides self-powered shaft monitoring, offering a solution for the development of intelligent, low-power ship systems.