无刷双馈发电机在电网故障时的动态响应分析

Dynamic Response Analysis of Brushless Doubly-Fed Induction Generator under Grid Fault

无刷双馈发电机由于取消了电刷与滑环,提高了可靠性。风力发电机组不间断运行的关键是风力发电机的低电压穿越能力,为了便于对无刷双馈发电机低电压穿越技术进行研究,根据无刷双馈发电机的数学模型分析了电网在发生对称故障与不对称故障时,功率绕组磁链变化以及控制绕组电压变化的动态过程,对不同电网故障时控制绕组瞬时电压值进行了计算,并对电网故障时的动态响应过程进行了仿真,为无刷双馈发电机低电压穿越保护电路的参数设计及控制策略的制定提供了理论依据。

Brushless doubly-fed induction generator has good system reliability due to the cancellation of the brush and slip ringcompared with DFIG.The low voltage ride-through （LVRT） capability is the key to realize the uninterrupted operation for the wind power generation.In this paper, the LVRT issuefor different grid faults is studied. The dynamic responses of the change of power winding magnetic linkage and the change of control winding voltage are analyzed when grid fault occurswith symmetrical fault and unsymmetrical fault respectively based on mathematical model of BDFIG. Theinstantaneous voltages of control winding are calculated and the dynamic responsesare simulated under different grid faults. The study work in this paper provides a theoretical basis for designing circuit parameters and control strategy for LVRT protection.