With the inception of the Argo program, the global ocean observation network is undergoing continuous advancement, with profiling buoys emerging as pivotal components of this network, thus garnering increased attention in research. In efforts to enhance the efficiency of profiling buoys and curtail energy consumption, a teardrop-shaped buoy design is proposed in this study. Moreover, an optimization methodology leveraging neural networks and genetic algorithms has been devised to attain an optimal profile curve. This curve seeks to minimize drag and drag coefficient while maximizing drainage, thereby improving hydrodynamic performance. Simulation-based validation and analysis are conducted to assess the efficacy of the optimized buoy design. Results indicate that the drag of the teardrop-shaped buoy with a deflector decreased by 9.2% compared to pre-optimized configurations and by 22% compared to buoys lacking deflectors. The hydrodynamic profile devised in this study effectively enhances buoy performance, laying a solid foundation for ocean thermal energy generation and buoyancy regulation control. Additionally, the optimized scheme serves as a valuable blueprint for the design of ocean exploration devices.

Combined with the rapid volatility and spatial distribution characteristics of wave energy, the output power of wave energy devices is relatively unstable. When the wave energy device group is connected to the grid, the power grid after the power generation device is converged may still experience a voltage dip, which will affect the power quality and system stability of the load grid. This paper is based on the modular multilevel converter (MMC) to develop the wave energy device group flexible direct current transmission (MMC-HVDC) system. Combining the internal topological structure of the system and the MMC mathematical model, the system compound control strategy under the island operation mode is proposed. The control system operates in a synchronous reference frame (SRF). In addition to the basic controller, it also includes a circulating current suppression controller (CCSC) and a zero sequence current suppression controller. A MATLAB/Simulink simulation model is established based on the actual project. The simulation results show that the system can effectively compensate for transient voltage sags. In addition, the system also has power quality adjustment capabilities such as low harmonic distortion, reactive power compensation and circulating current suppression.

A droplet concentrator for water wave consisting of multiple droplet-shaped cylindrical bodies is designed, based on the scattering cancelation method. A numerical model of wave–concentrator interaction is established using the commercial software Star-CCM+. The simulation results have proved that the amplification factor of the wave amplitude by this droplet concentrator is at most 5.09. From the analysis of the vortex field, the droplet-shaped structure exhibits superior hydrodynamic performance. From the perspective of coordinate transformation theory, the droplet-shaped wave concentrator has a higher coordinate transformation ratio. Therefore, the proposed droplet-shaped concentrator demonstrates enhanced performance. Furthermore, the effects of incident wave frequency, wave height, and the immersion depth of the concentrator on the performance are investigated. This study provides a valuable blueprint for the practical application of wave concentrators, which may have significant potential in wave energy extraction, thereby promoting the commercialization of wave energy.