Research On Characteristics Of Underwater Inductive Power Transfer

Due to the advantages of safety,reliability,flexibility and concealment,Wireless Power Transmission is gaining more and more attention as it provides a new way of transmitting electricity to various marine electromechanical equipments.This paper focuses on the analysis and study of the application of Inductive Power Transfer(IPT)underwater.Although IPT has been well developed in various applications on land,the electrical characteristics of seawater are significantly different from air,which will directly affect transmission performance.Coupled with the complexity of the underwater environment and the specificity of the application area,underwater IPT obviously faces more problems,and at present there is a lack of complete and detailed research on it at home and abroad.In order to reveal the transmission mechanism and performance of underwater IPT,and thus promote its development on ocean exploration and marine operations,this paper combines numerical computation and finite element simulation to model the time-harmonic field of a single-coil,dual-coil system carrying sinusoidal alternating current,and study the expression of eddy current loss and the influencing factors;the composition and distribution of other losses in underwater IPT are described and analyzed.The correctness and validity of the loss model proposed in the paper are experimentally verified.Characterizing various parameters of the coupling coil underwater,such as the change of inductance and capacitance,provides a basis for the establishment of the system circuit model.Underwater correction mutual inductance is introduced.New mathematical models are established for different compensation topologies,which directly equates the effects of seawater into the circuit,illustrates the frequency characteristics of the underwater IPT and theoretically explains the underwater frequency shift phenomenon.The analysis is proved by experiment.Finally,flexible coupling coil configuration is proposed to accommodate the appearance of the torpedo type of underwater device,and the variation of key parameters under the bending angle is studied.Two categories of flexible coil system configurations are designed,compared and optimized.What’s more,with the goal of coupling coefficient,their application situation and performance are demonstrated.The establishment of IPT system through field-path joint simulation illustrates the effect of the bending angle on the transmission efficiency.