Parameter Identification Method for Underwater Vehicle WPT System Based on Primary-Side Detection

In the realm of underwater wireless power transmission systems, it is crucial to acquire system parameters accurately to ensure output stability. However, measuring these parameters in underwater environments presents a huge challenge. As a result, simplifying measurements through parameter identification becomes essential. The circuit model of the underwater wireless power transfer (WPT) system may require adjustments due to seawater conductivity, and utilizing current parameter identification methods is applicable to air, which can lead to notable inaccuracies in underwater parameter identification. This article presents an analytical model of the mutual inductance in the underwater WPT system, analyzes its impact on output power and transmission efficiency, and proposes a mutual inductance and load parameter identification method suitable for underwater WPT systems. This method identifies mutual inductance and load values by measuring the input impedance of the equivalent load network on the inverter side at both resonant and nonresonant frequencies. The parameter identification model of the proposed underwater WPT system has been theoretically derived and experimentally verified using the seriesseries (SS) compensation topology. The experimental results illustrate that the proposed parameter identification method effectively identifies both the mutual inductance model and the load of the underwater WPT system, with the load identification error being less than 2% and the mutual inductance identification error being less than 5%. Furthermore, mutual inductance and load information can be obtained from the primary side without communication, and the output voltage is controlled with an accuracy of less than 1.2% through parameter identification.