双馈风力发电机组协调多目标非线性控制

为平抑双馈风力发电机组额定风速以上的转速和功率波动,基于协调无源性方法,提出一种同时考虑桨距角和转子励磁控制的协调控制策略。首先,在分析风力机特性和双馈感应发电机基本电磁关系的基础上,给出风力发电机组桨距角调节、转子励磁控制的四阶系统非线性模型。特别对风能利用系数进行了关于桨距角的多项式拟合,并对拟合的不确定性建模,确保了模型的准确性。其次,由Lyapunov方法设计前两阶鲁棒控制器,得到桨距角控制输入,再用协调无源性方法设计励磁控制部分,使得整个系统达到反馈无源,既保证了系统的鲁棒性,又保证了整个系统的渐近稳定性。最后,通过仿真验证了控制策略的控制效果,并与其他控制策略进行了比较,验证了该控制策略的有效性。

Multi-objective nonlinear coordinated control of doubly-fed induction generators

In order to suppress the fluctuations of the rotor speed and electrical power of the doubly-fed induction generator (DFIG) system when it works at a wind speed greater than the rated value, a new coordinated regulation strategy is proposed using the coordinated passivity techniques, with the pitch angle regulation and excitation voltage control simultaneously considered. First, based on analysis of the characteristics of wind turbines and the basic electromagnetic relationship of DFIGs, a four-order nonlinear model was established for regulation of the pitch angle and control of the excitation voltage of DFIGs. In particular, the formula of the wind power utilization coefficient and pitch angle was fitted with the polynomial function, and the uncertainty of the fitting result was modeled, ensuring the high accuracy of the system model. Secondly, pitch angle control was realized based on design of the former two orders of the robust controller using the Lyapunov techniques, and excitation voltage control was achieved based on the coordinated passivity techniques. Thus, the passive feedback of the whole system was obtained, and the system is both robust and tends to be stable. The simulation results validate the effect of the control strategy. The effectiveness of the present control strategy was also verified by its comparison with other control strategies.