The voltage source converter based high voltage direct current (VSC-HVDC) with flexible direct current (DC) converter valves serves as the core equipment in offshore wind power systems

playing a crucial role in the efficient grid connection of large-scale offshore wind farms. However

the complex operational environment of offshore wind farms and wind speed fluctuations pose significant challenges to the reliability of the sub-modules (SMs) of the converter valves. To address this issue

an accurate and efficient test method for the SMs under offshore wind power mission profiles is proposed in this paper. Firstly

the basic structure of the grid-connected system is introduced

and the mission profile of the converter valves on the wind farm side under steady-state conditions and wind speed fluctuations is analyzed. Secondly

the fundamental principles of mission profile emulation are elaborated

and a novel circuit topology suitable for testing multiple SMs under multiple mission profiles is proposed. Thirdly

the control strategies of the test system are proposed based on the actual mission profile of the converter valves

including a proportional-integral-resonant controller-based current control method and a balance control strategy-based capacitor voltage control method for the SMs under tests. Finally

a simulation model of the mission profile emulation test platform is established

and the feasibility and effectiveness of the proposed method are verified through steady-state and dynamic simulation results.