孤岛双馈异步风力发电机组自抗扰控制研究

Auto disturbance rejection control of doubly-fed induction generator for wind turbine in stand-alone mode

针对孤岛运行双馈异步风力发电机输出电压易受负载切换影响、PI控制器对电机参数依赖性高等问题,建立了包含励磁电流动态过程与电机参数误差的数学模型。将电机参数误差和励磁电流动态过程分别视为系统的内扰与外扰,应用分离性原理和零极点配置方法设计双闭环自抗扰控制器替代PI控制器,扩张状态观测器可实时估计系统总扰动,并通过前馈进行补偿。建立兆瓦级DFIG孤岛运行仿真模型进行验证,结果表明文章控制方法能够有效抑制负载切换引起的电压扰动和电机参数变化的影响,提高了系统抗扰动性能。

The voltages of stand-alone wind turbines with doubly-fed induction generators（DFIG）are easily affected by load switches, the performance of PI controller highly depends on the accurate parameters of DFIG. To solve those problems, a DFIG model with dynamic exciting current and parameter errors of generator is built. The parameter errors and dynamic exciting current of DFIG are considered as internal and external disturbances of an auto disturbance rejection controller（ADRC）.The double-loop ADRC is designed to replace PI controller based on the separation principle and the pole-zero placement method. An extended state observer of ADRC is used to estimate the total disturbance of the system in real-time, and the disturbance could be compensated by feed-forward. A simulation model of stand-alone megawatts DFIG with ADRC was established in Matlab/Simulink environment. The simulation results show that the proposed ADRC can actively suppress the DFIG voltage disturbance when load is switching or the DFIG parameters change. The disturbance rejection capability of the system is enhanced.