双馈感应风力发电机低电压穿越控制策略的理论分析与实验研究

A Low Voltage Ride-Through Control Strategy of Doubly Fed Induction Generator

分析了电网对称及非对称故障时,双馈感应风力发电机定子磁链的动态过程、电网故障过程中发电机定子磁链对转子的影响。在此基础上,分析了单靠改进转子变换器控制策略实现发电机低电压穿越的条件,提出一种利用软硬件结合的方法实现低电压穿越的控制策略,在电网严重故障时限制了双馈感应发电机定、转子电流,保护了双馈发电机励磁变换器,实现了快速地向电网提供功率支持。建立了双馈感应发电机低电压穿越控制模型和3kW双馈感应发电机励磁变换器低电压穿越控制实验系统。实验结果表明,本文提出的双馈感应发电机低电压穿越控制策略动态响应快、方法行之有效。

Based on an analysis of DFIG stator flux transient period during symmetric and asymmetric grid fault,its influence on DFIG rotor,the LVRT limiting condition using rotor-side converter（RSC） control strategy to achieve low voltage ride-through（LVRT） is found.A DFIG LVRT method combining the improved control strategy with hardware protect is studied when the limiting condition is not met.The method limits the stator＇s and rotor＇s over current,protects the rotor converter and provides power to the grid quickly during serious grid fault.A 3kW DFIG LVRT control experimental system is established.The experimental results prove that the LVRT control method of DFIG is effective.