The fault transient characteristics of offshore wind farms interconnected via flexible low-frequency transmission systems are greatly affected by the converter control links. Existing fault current calculation methods neglect the converter control-induced transient processes

leading to significant errors. This poses challenges for setting protection device parameters and designing fault ride-through strategies. To address these issues

this paper proposes an analytical fault current calculation method that accounts for the vector control characteristics of both the grid-side converter (GSC) of wind turbines and the modular multilevel matrix converter (M3C) station. Firstly

equivalent source models incorporating the post-fault active regulation effects of the converters are developed. Secondly

to resolve the coupling problem of fault currents from the two converter sides at the fault resistance

this paper implements an effective system decoupling strategy based on partitioned calculations. To address the coupling issue between the d- and q-axis components of the M3C low-frequency side fault current

this paper also proposes a novel method employing common-factor-based decoupling operations

which enables the analytical calculation of the M3C station dq-axis currents

accurately capturing the transient response of its dual-loop control systems. Finally

the model is built on both the PSCAD/EMTDC simulation platform and the RTDS experimental platform. The simulation and experimental results validate the accuracy of the proposed method. Furthermore

the comparison with existing fault analytical calculation methods demonstrates the superiority of the proposed approach.