基于自抗扰矢量控制的DIFG系统低电压穿越策略

Based on Active Disturbances Rejection Vector Control of DFIG for Low Voltage Ride-Through

基于PI调节器的传统矢量控制设计,均以双馈发电机的三阶模型为基础,忽略了励磁电流的暂态过程,电网发生低电压故障时,控制性能不佳。为提高DFIG系统的低电压穿越能力,将自抗扰控制和矢量控制相结合,提出了系统在故障下的自抗扰矢量控制策略,通过扩张状态观测器估计出系统总扰动并予以补偿,削弱故障对控制性能的影响。分析对比了传统矢量控制、改进的定子磁链补偿控制及自抗扰矢量控制,基于PSCAD/EMTDC平台进行暂态仿真研究。仿真结果表明,自抗扰矢量控制动态性能良好、鲁棒性强,能更为有效地抑制转子侧暂态电流,提高系统低电压穿越能力。

The traditional vector control were designed based on third-order model of DFIG, because of ignoring the transient excitation current, the control performance was poor during voltage sags fault. In order to enhance the LVRT capacity of DFIG system, the ADRC Vector Control were proposed by combining vector control with the ADRC controller, the influences of disturbances on the wind energy generation system were estimated and compensated by the extended state observer. With PSCAD/EMTDC simulation platform, the dynamic process of DFIG system was simulated during the voltage sags fault. By comparing the traditional PID control、improved control and ADRC control strategy, the results showed that the ADRC control system could effectively restrain the transient current on the rotor and state winding, which helps to enhance the LVRT ability of DFIG.