中文摘要：

提出基于改进式双馈感应风力发电机模型的无功协调控制策略,以提高电网故障下双馈风机的无功调节能力。在DIg SILENT/Power Factory平台上,搭建改进双馈风机的详细模型。利用DC-Chopper和串联动态制动电阻代替Crowbar保护电路,以实现背靠背变流器持续为电网提供无功支撑。通过协调分配风电机组定子和网侧变流器及补偿单元之间的无功功率参考值,来提升电压控制点的电压。与传统控制方法相比,所提控制策略可以充分利用变流器的无功发生能力,扩大电网故障时风电场的无功输出范围,减小无功补偿装置的投资,并提高风机的低电压穿越能力。

英文摘要：

Based on an improved model of doubly-fed induction generator（DFIG）,a coordinative reactive power control strategy is proposed to strengthen its reactive power adjustment under fault in power network. A comprehensive improved model of DFIG is built on DIg SILENT/Power Factory platform. Instead of protective Crowbar,DC-Chopper andseries dynamic braking resistor（SDBR）are used to assist back-to-back converters with the capability of providing reactive power continually for the grid. The voltage of control point is improved by distributing the reference value of reactivepower among stator,grid side converter and compensation unit. Compared with the traditional control method,the proposed control strategy can make full use of reactive power output of converters,enlarge the reactive power output ofwind farm under fault,reduce the investment of reactive compensation devices and enhance the capability of low voltage ride through（LVRT）.