High power density integrated wireless power transfer method for underwater intelligent sensors

This paper proposes a high-power-density integrated undersea wireless power transfer (UWPT) system for underwater intelligent sensors, which features anti-offset capability and electromagnetic shielding compatibility. Firstly, the high-frequency inverter designed for the UWPT system integrates auxiliary power supplies, control circuitry, driving components, and semiconductor switching devices. By employing zero-voltage switching (ZVS) technology to minimize high-frequency switching losses, the design enables a more compact structure and enhanced reliability. Secondly, to achieve high transmission efficiency, this paper establishes a nonlinear rectifier bridge load equivalent model based on the proposed topology. It reveals the mechanism by which the rectifier diode voltage drop affects load conversion and quantitatively analyzes how system efficiency varies with load. This analysis helps reduce calculation errors in determining the optimal load. Furthermore, the adoption of ferrite cores enhances the coupling coefficient and reduces eddy current losses resulting from the leakage of high-frequency alternating magnetic fields in the circuit. Finally, a 100 W prototype is built with a 500 kHz switching frequency to validate the proposed design. Experimental results demonstrate that the UWPT system exhibits strong robustness in both air and salt water environments. The maximum efficiencies achieved are 91.4% in air, and 89.6% in salt water.