中文摘要：

提出了一种面向直流输电的双馈风电机组并网拓扑及其控制策略,该拓扑利用双馈风电机组内部直流母线接入直流电网,采用间接气隙磁链定向策略及气隙电势定向策略控制变流器,确保双馈感应发电机（doubly-fed induction generator,DFIG）生成幅值和相位稳定的三相正弦气隙电势,同时灵活调节DFIG向直流母线输送的有功功率。此外还分析了所提拓扑下DFIG全转速范围内的控制策略。最后,构建了DFIG直流并网输电实验系统,验证了所提拓扑及其控制策略的可行性。

英文摘要：

A kind of HVDC power transmission oriented grid-connection topology and corresponding control strategy for wind farm composed of doubly fed induction generators（DFIG） is proposed. In the proposed topology the DFIG is connected to power grid via the DC bus inside the DFIG, and the converter is controlled by indirect air gap flux linkage orientation strategy and air gap electromotive force（emf） orientation strategy to ensure that a three-phase sinusoidal emf can be generated in the air gap of DFIG, meanwhile the active power transmitted from DFIG to DC bus can be flexibly adjusted. Besides the control strategy within the whole speed range of DFIG under the proposed topology is analyzed. Finally, the feasibility of the proposed topology and corresponding control strategy is validated by a constructed experimental system for the DC grid-connection and power transmission of DFIG.