海上风电经CSC-MMC混合直流送出系统及其控制策略OA

An offshore wind power transmission scheme based on an active-commutated current-source convert-er-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 tech-no-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.