An offshore wind power transmission scheme based on an active-commutated current-source converter-modular multilevel converter (CSC-MMC) hybrid HVDC link is a promising solution for DC export of offshore wind farms. The offshore converter station employs a CSC to reduce platform volume and weight while regulating the offshore AC bus voltage and frequency. The onshore station adopts a hybrid half-/full-bridge MMC

providing both negative DC voltage capability and frequency support for the receiving grid. This paper first investigates the operating characteristics of the proposed system and compares it with alternative offshore HVDC export schemes

demonstrating favorable techno-economic potentials. Subsequently

a mathematical model is developed

steady-state control strategies are designed

and a black-start scheme tailored to the hybrid system is proposed. A communication-free coordinated control strategy is then presented

in which receiving-end frequency variations are conveyed via DC voltage

enabling active frequency support. Finally

PSCAD/EMTDC simulations under black-start

rated operation

wind-speed fluctuations

and sudden load increases validate the feasibility and effectiveness of the proposed scheme and controls.