Magnetically enhanced quasi-zero-stiffness galloping harvester for efficient wind energy harvesting and autonomous sensing

This study presents an enhanced quasi-zero-stiffness galloping-based piezoelectric energy harvester (EQZS-GPEH) for efficient wind energy harvesting and self-powered wind speed sensing. It employs a five-magnet configuration to expand the QZS region, thus effectively reducing the cantilever beam stiffness, lowering the onset wind speed, and amplifying the dynamic response. The experimental results demonstrate that the EQZS-GPEH delivers a maximum power output of 1.55 mW at a wind speed of U = 4.834 m/s and a load resistance of RL = 0.7 MΩ, representing a 294% improvement over the traditional galloping-based piezoelectric energy harvester (T-GPEH) and a 142% improvement over the conventional QZS galloping-based piezoelectric energy harvester (CQZS-GPEH). Beyond enhanced performance, the EQZS-GPEH also exhibits a highly linear relationship between vibration frequency and wind speed (R2 > 0.99), enabling accurate wind speed estimation. Leveraging this characteristic, an analog-to-digital converter circuit was developed to process harvester output and estimate wind speed, achieving a relative error of <5% compared to reference instrumentation. Integrated with the EQZS-GPEH, this forms a fully self-powered wind speed sensing system. These results demonstrate the EQZS-GPEH as a high-performance self-sustaining solution for distributed energy harvesting and sensing, making it highly promising for future IoT applications.