An Adjustable Quasi-Zero Stiffness Electromagnetic Generator With a Tilt Pendulum for Efficient Ultra-Low Frequency Wave Energy Harvesting

As the field of marine intelligent sensing systems continues to evolve rapidly, there is a pressing need for effective energy harvesting techniques to overcome the constraints associated with existing power supply solutions. In this article, we introduce an adjustable quasi-zero stiffness electromagnetic generator (AQZS-EMG) specifically engineered for the efficient extraction of ultra-low frequency vibrational energy from sea waves. By implementing a tilt pendulum design, we are able to reduce and fine-tune the natural frequency of the AQZS-EMG to accommodate ultra-low frequency broadband operation. Our device features four electromagnetic energy harvesting units evenly distributed across four directions, facilitating multidirectional energy harvesting. Through a combination of theoretical modeling and empirical tests under various conditions, the AQZS-EMG reaches a maximum output power of 32.01 mW under the excitation frequencies of 0.5 to 1.1 Hz, demonstrating its potential in scavenging blue energy.