针对分布式海上风能汇集与向陆上电网传输过程中面临的挑战，同时减轻海上输电系统短路故障的影响，本文提出了一种四端口柔性直流换流阀拓扑。该拓扑具有两个输入端口和两个输出端口，可以通过直流电缆实现多个海上风电场的互联，并将电能输送至陆上电网。为提高系统可靠性，本文引入一种故障穿越控制策略，用于应对直流侧短路故障。该拓扑在每个端口采用模块化多电平换流器( Modular Multilevel Converter，MMC )调节直流电压，并通过主从控制实现交流母线电压和功率传输的稳定。当直流侧发生故障时，通过主从变换器的动态切换保证系统的稳定性，并限制故障电流。此外，提出的无通信策略可以通过减少海上风电场的出力来维持系统的功率平衡。最后，通过PLECS平台仿真验证了所提拓扑和控制策略的有效性。

Offshore wind power represents a significant renewable energy source, with large-scale grid integration being a key development trend. This paper addresses the challenges of collecting distributed offshore wind energy and transmitting it to onshore grids, while mitigating the impacts of short-circuit faults in offshore transmission systems. A novel four-port flexible DC converter topology is proposed, featuring two input ports and two output ports. This topology interconnects multiple offshore wind farms via DC cables and delivers power to separate onshore grids. To enhance system reliability, a fault ride-through (FRT) control strategy is introduced to manage DC-side short-circuit faults. The topology employs modular multilevel converters (MMCs) at each port to regulate DC voltage, with a master-slave control scheme to stabilize AC bus voltage and power transmission. During DC-side faults, dynamic switching between master and slave converters ensures system stability while reducing fault currents. Furthermore, a communication-free strategy maintains power balance by curtailing offshore wind farm output. Simulation results on the PLECS platform validate the effectiveness of the proposed topology and control strategies.