Direct Pressure-tolerant DC Transformer Scheme and Control Method Applied to Subsea Power Supply

In order to realize the high-power density design of deep-sea DC transformer, the new quasi-series half-bridge module is adopted to reduce the number of cascaded units in the overall DC transformer scheme. A device solution for direct pressure-tolerant DC transformer was built by screening and testing a large number of power electronics devices and optimizing key components. Then the insulating liquid is filled into the flexible pressure-averaging enclosure to ensure the insulation and heat dissipation of the internal transformer, the scheme can remove the thick metal pressure-bearing enclosure and additional heat dissipation equipment, effectively improve the power density. In addition, the corresponding closed-loop control method and soft-start control strategy are proposed, and finally through the experiments under the standard atmospheric pressure and simulated deep sea environment, the feasibility of direct pressure-tolerant DC transformer scheme is verified.