Considering the effect of eddy losses on the transmission efficiency of underwater wireless power transfer (UWPT) systems

this paper proposes a control strategy that utilized impedance regulation at the receiving side for efficiency optimization. By constructing a mathematical model of UWPT system efficiency

the maximum efficiency condition of the system is obtained. It is found that a strong coupling relationship existed between the efficiency and the load reactance. This article is based on the principle of “power first

efficiency second”

where an active rectifier is employed to maintain output power as the primary control objective. To achieve the secondary objectives of eddy current suppression and efficiency improvement

an auxiliary H-bridge is introduced and coordinated with an active rectifier

using the secondary loop current phase as the control variable. A collaborative control method for the auxiliary H-bridge and active rectifier is proposed

which achieved the dual objectives of impedance matching and output control. This paper constructs a prototype of 787 W for verification. Experimental results showed that compared with traditional LCC-S compensation

the proposed method improved the efficiency by 1.58% under rated conditions. Analysis of its loss distribution revealed that the proportion of eddy loss decreased from 82.8% to 71.1%

which verifies the effectiveness of the proposed collaborative control strategy.