Hybrid Electromagnetic and Piezoelectric Wind Energy Harvester Integrated With Halbach Magnet Array and Magnetic Plucking: Modeling and Experimental Verification

To enhance the energy-harvesting performance and environmental adaptability, this paper proposes a hybrid electromagnetic and piezoelectric wind energy harvester (HEPEH) integrated with the Halbach magnet array and magnetic plucking frequency up-conversion. A theoretical model is established and experimentally verified to explore response characteristics. The driving magnets with an alternating magnetic pole arrangement have superior maximum average output power than the identical magnetic pole arrangement because of the compressed adjacent positive (or negative) peak magnetic plucking period and the amplified magnetic plucking force. Compared with the identical magnetic pole arrangement, the maximum average output power has increased by 1.5 times (reaching 11.03 mW). Results show that vibration interference induced by the mismatch phase between the magnetic plucking force and the vibration of the piezoelectric beam affects energy-harvesting performance. This study quantifies the influence of the gap distance between the Halbach magnet array and coil on the electromechanical coupling coefficient. Sensitivity analysis indicates the harmonic amplitude of the electromechanical coupling coefficient increases 1.36 times while the gap distance decreases from 6 mm to 4 mm. The average output power from the single coil is increased by 1.91 times, and has reached 2.87 mW at 8 m/s. The optimization strategy is provided, and the dependency between the upper effective rotational frequency with the damping ratio, natural frequency, and driving magnets is analyzed. Overall, this work provides a view of integrated wind energy harvesters, which may offer a guideline for the design of wind energy harvesters.