Modular multilevel converter （MMC）-based DC transmission systems have gradually become an important way for integrating offshore wind power due to its advantages such as high efficiency, flexible control, and easy expansion to multi-terminal systems. The active power of offshore wind farms is random and fluctuating, and large-scale power fluctuations may cause problems at the receiving end converter stations, such as power limit violation, DC voltage limit violation, and power circulation between AC and DC systems. To solve these problems, two power coordination control strategies for the receiving-end of large-scale offshore wind power via flexible HVDC transmission systems are proposed. Firstly, the basic structure of the transmission system and the MMC control strategy are introduced. Then, the active power self-balancing control strategy at the receiving-end and the common-outer-control-loop-based DC voltage control strategy at the receiving-end are designed. These two strategies feature distinct technical characteristics, yet both enable rational active power distribution among multiple receiving-end converter stations, thereby preventing unnecessary power limit violations, voltage limit violations, and power circulation issues. Finally, the effectiveness of the two control strategies is verified by PSCAD/EMTDC simulation.