基于模块化多端口直流变换器的海上风电直流汇集拓扑研究OA

To handle unbalanced power during the series connection of offshore DC wind turbines,enable online switching,and achieve fault isolation,this paper proposes an offshore wind power DC networking topology based on a modular multi-port DC converter.The DC wind turbine achieves power collection and step-up of the output port voltage through the converter,reducing the number of power conversion stages and the offshore converter station.The power devices are shared between the converter sub-modules and the power balance circuit,lowering hardware costs and stabilizing the output port voltage despite wind speed fluctuations.Moreover,the converter can isolate faults on the high-or low-voltage side,enhancing system flexibility.This paper first analyzes the normal and fault operation conditions of series-connected offshore wind power DC collection systems and the power transmission principle of the DC converter.Subsequently,the control strategy for the proposed DC collection scheme is designed,and fault-isolation and fault-ride-through methods for wind turbines under high-and low-voltage-side faults are presented.Finally,a simulation model of offshore wind power collection system based on the modular multi-port DC converter is established to valid ate the effectiveness and feasibility of the proposed collection scheme.