电网电压跌落时双馈风力发电系统的改进控制策略研究

Research of the improved control strategy for a double-fed generation system under grid voltage dip

针对常规控制无法满足双馈异步电机(DFIG)低电压穿越技术要求的问题,在常规控制模型的基础上,分析了定、转子故障暂态过程,找到了影响转子过电流和直流母线过电压的原因。并提出一种新的基于电流前馈补偿的控制策略,即在转子侧d轴参考电流上附加一个反映定子磁链暂态衰减的前馈分量;在网侧d轴参考电流上附加一个反映两侧功率变化的前馈分量。最后,在PSCAD/EMTDC平台下,搭建仿真模型,通过对在电网电压跌落时,控制方案改进前后运行结果的仿真对比,验证了所提改进控制策略的有效性。

According to the problem that the traditional control scheme can not meet the requirement of low-voltage ride-through for DFIG, in this paper, based on the analysis of the stator and rotor transient process, we find the causes which affect the rotor over-current and DC bus overvoltage, and propose a new feedforward compensation method based on current control, that is, in the rotor side, adding a feedforward component which can reflect the attenuation of stator flux transient; in the grid side, adding a feedforward component which can reflect the power change between the two sides of converter. Finally, a DFIG model is built under PSCAD/EMTDC platform, the validity of this new control strategy is verified by simulation results through network voltage dip.