Hybrid triboelectric-electromagnetic generator for self-powered wind speed and direction detection

Abstract With the increasing demand for environmental wind information in many engineering fields, self-powered wind detection (SWD) by harvesting ambient wind energy has become the focus of contemporary research. This study proposes a hybrid triboelectric-electromagnetic generator (HTEG) for SWD. The HTEG consists of a rolling free-standing mode triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG). The rolling element material and number of magnets have distinct influences on the output voltage and current of the TENG and EMG. Under a rotating speed of 300 r/min, the root mean square (RMS) power density of the TENG became approximately 3 μW/g, and that of EMG was approximately 10 μW/g. The RMS values of the TENG output current and EMG output voltage were utilized as wind speed detection indicators. A variable wind speed test was carried out to verify the feasibility of the HTEG for wind speed detection. By preserving one magnet and aligning it with a wind vane, the structure of the EMG was slightly adjusted for wind direction detection. A series of variable wind direction tests were conducted to show that the wind direction could be detected by synchronously observing the changes in the induction voltages of the eight coils of the EMG. Load capacitance charging and continuous operation tests were also carried out respectively to illustrate the self-power capability and reliability of the HTEG. By assembling two HTEGs back-to-back on the bracket, an SWD prototype that can monitor wind speed and direction simultaneously was achieved and applied in an actual environment. The results showed that the proposed HTEG has good prospects for engineering applications.