海洋环境对水下无线电能传输系统的影响机理研究进展

Countries have been exploring marine resources for the past few decades with the progress and development of ocean science and technology. As the vital carrier for underwater resource exploration and military patrol, unmanned underwater equipment has become a research hotspot in the field of marine engineering, which has a wide range of economic, scientific, and military values. Typical unmanned underwater equipment mainly includes autonomous underwater vehicles, remotely operated vehicles, autonomous underwater gliders, and submerged buoys. With the progress of technology and the improvement of demand, the problems exposed by traditional energy supply methods have gradually become the biggest weakness restricting its self-sustainability, seriously limiting the autonomy and mobility of UUE. Wireless power transfer technology is gradually becoming a novel type of underwater power supply mode for solving the energy supply issues of underwater equipment. It has incomparable technical advantages over traditional power supply methods and effectively improves charging safety, reliability, convenience, and concealment. The application of underwater wireless power transfer technology can automate the power supply of unmanned underwater equipment, which may almost completely get rid of the need for manual operation. Since Marin Soljačić from the Massachusetts Institute of Technology first proposed their medium-range wireless power transfer system as a leading role in academia, the wireless power transfer technology has been rapidly developed due to its unique advantages. In recent years, wireless power transfer technology has been widely researched and applied in low-power scenarios such as cell phones, wearable devices, implantable medical, smart home products, and high-power areas such as electric vehicles, unmanned aerial vehicles, and aerospace equipment. These studies were conducted in air medium, while wireless power transfer technology has increasingly been expanded to seawater medium due to advancement and great demand. However, due to the complexity of the marine environment, underwater wireless transmission systems face more challenges than land-based wireless transmission systems represented by electric vehicles. Underwater wireless power transfer technology encounters issues with electromagnetic wave attenuation, irregular seawater current interference, and underwater precision docking as a result of the particular complexity of the marine environment. So far, the underwater wireless energy transfer still has not been fundamentally addressed. With the continuous deepening of research at home and abroad, underwater wireless energy transmission technology has begun to expose some urgent research problems and technical difficulties. The main contributions of this paper are as follows: (1) A comprehensive overview of the influence of seawater medium on wireless power transmission systems is given, and the influence mechanism and technical research progress of typical influencing factors such as additional eddy current loss, distributed capacitance, deep-sea piezomagnetic effect, and submarine current perturbation in the marine environment and seawater medium are analyzed. (2) Energy efficiency degradation and related problems caused by seawater medium parameters and marine environment are analyzed and discussed in detail. In view of the hot issues such as system detuning in seawater environment, optimal frequency interval seeking, anti-detuning magnetic coupler, valuable research ideas such as system topology pre-compensation design, system frequency dynamic tracking and regulation, and control methods under underwater no-communication or weak-communication conditions are put forward. (3) The potential problems and challenges of wireless power transmission technology applied to underwater unmanned equipment are elaborated, and the future direction of technological development of underwater wireless power transmission systems that deserves attention is envisioned.