电网不对称故障下双馈风力发电机组的LVRT研究

摘要

Based on the effect of the asymmetric grid voltage on DFIG and the positive and negative sequence mathematical model of DFIG, this paper analyses the structure of output active and reactive power of system under asymmetric grid voltage condition, the positive and negative sequence components separation control and bond with the traditional Crowbar circuit control in the rotor side and the net side is proposed, then we analyses the resistance and switching time of crowbar. Finally, the control strategy is simulated by Matlab, and the simulation results demonstrate that the control strategy can eliminate the effect of the negative sequence current and realizes the asymmetrical faults ride-through.%本文在研究了电网电压不对称对双馈风力发电机（DFIG）的影响以及DFIG正、负序数学模型的基础上，分析了电网电压不对称条件下对系统输出有功、无功的构成，提出在转子侧和网侧采用正、负序分量分离控制与传统Crowbar电路结合的控制策略，并对Crowbar阻值和投切时间进行分析。最后通过Matlab对系统进行验证，仿真结果表明在电网不对称故障时，这种控制策略可以消除负序电流对定子侧有功功率、无功功率、电磁转矩和直流侧电压的影响，实现不对称故障穿越。