中文摘要：

双馈风电机组（doubly fed induction generator，DFIGl在电网电压故障以及故障恢复作用下的磁链变化将导致转子过电压或过电流，威胁转子侧的变换器。采用串联耦合补偿（series coupled compensation，scc）的新型电压穿越方案，SCC通过耦合变压器串接在发电机输入端，它能克服电网多种故障对风电系统的影响。提出的控制策略有如下优势：能削弱故障下机组定子、转子电流暂态成分，克服了定、转子绕组不平衡发热的问题，延长了风电机组使用寿命；在电网故障下发电机组仍能平稳输出有功、无功功率；在整个故障运行过程中，DFIG系统转子侧变换器始终可控，从而为故障电网提供无功功率支持成为可能。在电网对称和非对称故障条件下，采用PSCAD／EMTDC建立了1MWDFIG风力发电系统模型，仿真结果表明该控制方案可以提高DFIG的故障穿越能力。

英文摘要：

Flux variation of doubly fed induction generator （DFIG） under grid fault and fault recovery leads to rotor overcurrent or rotor overvoltage, and it hazards to the converter at rotor side. For this reason a new low voltage ride through scheme, in which a series coupled compensation （SCC） is connected in series to generator＇s input terminal via coupling transformer, is proposed to overcome the affections on wind power system due to faults occurred in power grid. The superiorities of the proposed control strategy are as following： the transient current component in both rotor and stator of DFIG can be weakened, thus the unbalanced heating of both rotor and stator windings can be suppressed and the service life of DFIG can be prolonged; DFIG can still output active and reactive power steadily; the converter at DFIG＇s rotor side is controllable all along during the whole accident operation, thus it is possible to provide reactive power support to faulty power grid. Under the condition of symmetrical and asymmetrical fault occurred in power grid, a simulation model of wind power generation system with capacity of 1 MW is established by PSCAD/EMTDC, and simulation results show that using the proposed control scheme the ride through capability of DFIG under fault occurred in power grid can be improved.