DFIG定子绕组匝间短路故障下的调频优化策略研究

Research on Frequency Modulation Optimization Strategy forDFIG Stator Winding Inter-turn Short Circuit Fault

定子绕组匝间短路故障是造成双馈风力发电机功率突变,进而导致系统频率下降常见的高风险故障,同时由于速度和频率之间的解耦控制,在频率波动时很难对系统提供动态支持。针对上述问题,提出基于附加转矩控制的复合频率控制策略。首先构建定子绕组匝间短路故障数学模型,分析故障对频率的影响特性,然后基于传统的频率控制方法提出基于附加控制器的复合惯性频率控制策略;最后通过仿真平台验证所提控制策略在定子绕组匝间短路下的表现特性。结果表明,复合频率控制降低了频率变化率,减少了定子绕组匝间短路故障后频率的漂移。复合频率控制在定子绕组匝间短路下能够提供频率的动态支持,改善了匝间短路故障下弱电网的频率下降问题,提高了系统的鲁棒性。

Research on frequency modulation optimization strategy for doubly fed induction generator(DFIG)stator winding inter-turn short circuit(SWITSC)fault is a common high-risk fault that causes sudden power changes in doubly fed wind turbines,leading to a decrease in system frequency.At the same time,due to the decoupling control between speed and frequency,it is difficult to provide dynamic support to the system during frequency fluctuations.To address the above issues,a composite frequency control strategy based on additional torque control was proposed.Firstly,a mathematical model of stator winding inter-turn short circuit fault was constructed,and the impact characteristics of the fault on frequency were analyzed;then,based on traditional frequency control methods,a composite inertial frequency control strategy based on an additional controller was put forward;finally,the performance characteristics of the proposed control strategy under stator winding inter-turn short circuit were verified through simulation platform.The results show that composite frequency control reduces the frequency change rate and frequency drift after stator winding inter-turn short circuit faults.Composite frequency control can provide dynamic frequency support under SWITSC,improve the frequency drop problem of weak power grid under inter-turn short circuit fault,and enhance the robustness of the system.