Design and Simulation of DC Transmission Power Supply System with Umbilical Cables for Deep-Sea Underwater Equipment

Deep-sea underwater equipment as a pivotal instrument for oceanic exploration and resource exploitation, whose performance and efficiency are highly dependent on the stability of the power supply system (PSS). Conventional AC PSS utilizing umbilical cables suffer from drawbacks such as low transmission efficiency and significant voltage fluctuations, leading to compromised power stability and quality. In this paper, a high voltage DC(HVDC) transmission PSS based on umbilical cable is designed and simulated. The system converts the ship-borne 380 V alternating current into 3000 V DC through the step-up and rectification links, and then efficiently transmits it to the underwater equipment through the long-distance umbilical cable. The system meets the diverse load requirements through a precise energy conversion architecture. A part of the DC power drives the high-voltage asynchronous motor directly through the inverter, the other part generates three DC voltage levels of 800, 200 and 24 V through a dual active bridge (DAB) converter and a subsequent multi-stage step-down converter. Furthermore, a backup battery energy storage system (BESS) is integrated, which is charged under normal operating conditions and switched to the discharge mode when the main power supply fails. A complete simulation model of PSS is constructed by MATLAB/Simulink, which verifies the feasibility and effectiveness of the proposed DC power supply scheme. The research results provide a basis for PSS design, parameter optimization and clear operation constraints.