Analyzing Sea Environment's Effects on Inductive Power Transfer Systems: Equivalent Circuit Parameters and Performance Analysis

In this paper, the component-level and systemlevel influences of sea environments on the inductive power transfer (IPT) system are investigated. Archimedean coils are placed on the seabed and under the underwater unmanned vehicle (UUV) to recharge UUV's battery during its marine life monitoring mission and prolong its mission duration. However, seawater, characterized by its conductivity and relative permeability, acts as an external medium for the IPT system and influences its equivalent circuit parameters (e.g. self and mutual inductances and resistances). To study these influences, finite element method (FEM) studies are performed, and the impacts of the watery external medium on the magnetic flux lines distributions are investigated. Also, the process of inducing eddy currents in the watery external medium is analyzed and illustrated. Besides, an analytic method is proposed to reflect the impacts of the external watery medium on the equivalent circuit parameters of the IPT system. A preliminary analysis is also performed to study the impacts of the watery medium on system-level performances of the IPT system (e.g. output power, efficiency). The obtained results from theoretical and FEM studies are cross-verified by performing experimental studies over a prototype IPT system.