Study of an Electromagnetic Ocean Wave Energy Harvester Driven by an Efficient Swing Body Toward the Self-Powered Ocean Buoy Application

Ocean wave is one of the promising renewable energy sources all around the world. In this paper, an electromagnetic ocean wave energy harvester (OWEH) based on efficient swing body mechanism is presented. A swing body senses the ultra-low frequency wave motion and drive the rotor of an electromagnetic power module (EPM) rotating at high speed through transmission gears. A series of electromagnetic and dynamic simulations were carried out to optimize the power generation capability of the OWEH. Additionally, the power management circuit is specially designed such that the generated power is able to charge a lithium battery and discharge an external load automatically. The OWEH is installed inside an ocean buoy and tested in the Yellow China Sea. When the peak wave height is greater than 0.6 m, the maximum peak-to-peak output voltage is 15.9 V. The corresponding output power is as high as 0.13 W and the maximum power density is 0.21 mW/cm3, where the internal resistance of the OWEH is 122 Ω. Due to the high performance and adaptability, the OWEH can potentially power many low power components, which opens a promising way for improving the life of ocean buoys. Considering the small dimension of 10 × 10 × 6.3 cm3, this OWEH can be mounted inside most buoys easily and realize the self-powered ocean buoys in the near future.