A Frequency Optimization Method Considering Acoustic Cavitation for Maximizing Received Power in Underwater Wireless Ultrasonic Power Transfer Systems

Underwater Wireless Acoustic Power Transfer (UWAPT) systems face severe efficiency limitations from acoustic cavitation during high-power operation. This paper presents a comprehensive optimization method to mitigate this limitation. A cavitation threshold model, derived from the linearized Rayleigh–Plesset equation, is integrated with an acoustic absorption model to determine optimal operating frequencies for maximizing received acoustic power while avoiding cavitation. The optimization method effectively addresses the trade-off between cavitation thresholds and frequency-dependent absorption. Simulation experiments demonstrate the benefit of the proposed method, achieving a significant enhancement in power transfer efficiency compared to UWAPT systems without frequency optimization. For example, received power at 10 m transmission distance and 50 m operating depth is increased by 17.8%. Further analysis shows that the optimal frequency is influenced by environmental factors such as depth, salinity, and transmission distance. Simulation experiments in diverse underwater environments verify that the proposed method provides a robust solution for enhancing the efficiency and reliability of UWAPT systems.