一种新型的双馈风力发电系统LVRT技术研究

Research on doubly-fed induction generator low voltage ride-through based on a new technology

目前,风力发电机单机容量及风电场并网容量不断增大,风力发电在电网中所占比重越来越大。随着并网规则的日益严厉,保证风力发电机组在电网电压短时跌落时不解列,已成为一个强制性问题。此处首先研究了双馈电机在电网电压跌落时定子电流的电磁暂态过渡过程,并对其进行了仿真频谱分析,进而提出了基于考虑定子励磁电流动态过渡过程的双馈电机低电压穿越控制策略,并与传统的矢量控制策略进行仿真对比分析,改进控制策略可以有效抑制转子侧冲击电流,提高了双馈风力发电系统的不间断运行能力。最后,在实验室双馈风力发电实验平台上予以实验验证,实验结果表明所用控制方案的可行性与有效性。

At present, along with increasing power output of the single generator unit and wind power grid-connect- ed capacity, the proportion of wind power is even larger in the grid power, the grid-connected rules is more strict, and to ensure the wind power unit not to be out-of-step under grid voltage dip becomes a mandatory problem. The electromagnetic transient process is firstly analysed under grid voltage dip, the simulation spectrum analysis is also done, and then the low voltage ride-through （LVRT） control strategy by considering the stator electromagnetic tran- sient process is proposed. The simulation and contrast analysis shows that the improved control strategy can restrain the rotor current impact effectively, and can increase the uninterrupted operation ability of doubly-fed induction generator （DFIG） under grid voltage dip. Finally, the experiment is finished in the laboratory DFIG platform, and the experimental results verify the feasibility and effectiveness of the proposed control strategy.