Time-Sharing Transmission Method for an Undersea Magnetically Coupled Wireless Power and Data Transfer System

Waves, currents, and salinity gradients in the marine environment are inherently complex and significantly impact the performance of both power and data transmission through seawater, especially under turbulent and conductive conditions. Notably, the conductive nature of seawater presents a considerable challenge for undersea wireless power and data transfer (UWPDT) system in such an environment. Consequently, UWPDT systems essentially require specialized circuit designs that include dedicated interference mitigation measures. This paper therefore presents a magnetically coupled UWPDT system that is suitable for such undersea marine applications, utilizing a high-frequency alternating electromagnetic field. The presented UWPDT system shares a coupled coils’ channel and uses time-division multiplexing to transmit both power and data without any interference between them. Over any transmission cycle, both power and data are transmitted in separate time periods. The data is modulated using the frequency shift keying (FSK) method, while power transmission occurs at 86 kHz. The carrier frequencies of the two signals are set to 1 MHz and 2 MHz, respectively, for FSK modulation. Experimental results verified that the presented UWPDT system can transmit state information, such as battery voltage, current, and temperature, while charging underwater vehicles in a salty water pool environment. The system achieved a maximum power transmission efficiency of 91.3% when transmitting 200 W power level over a 4 cm distance between the transmitter and receiver coils, with a data transmission rate of 200 kbps.