基于二自由度的双馈风力发电系统并网控制策略

Grid-Connected Control Strategy of Double-Fed Wind Power System Based on Two-Degree-of-Freedom

控制系统调节器的设计直接影响了整个双馈风力发电系统的动态性能和稳态性能,甚至整个电力系统的稳定性。针对双馈风力发电系统一般将其内环整定为Ⅰ型系统时其抗扰性能不佳的缺点,并且结合Ⅰ型系统动态响应较快、超调较低的特点,提出了基于二自由度的电流内环Ⅱ型系统的设计方法,在对系统的快速性能和抗干扰性能进行折衷考虑下,对系统在不同自由度系数情况下的过渡过程进行了仿真分析,通过合理选择自由度系数,在较大地增强了系统抗干扰性能前提下,降低了系统的超调量。最后在实验室11kW双馈风力发电系统平台上进行试验,结果表明,提出的基于二自由度的双馈风力发电并网控制策略提高了系统的抗干扰性,同时系统还具有较快的动态响应性能,解决了系统并网电流产生低频振荡的问题,验证了理论分析和控制策略的有效性。

The regulator design of control system dominates the dynamic performance and steady performance of doubly-fed induction generator（DFIG） power generation system,and even dynamic stability of entire power system.Because of its fast dynamic response,wind power systems inner current loop are generally adjusted to type Ⅰ system,but it also has an obvious shortcoming in anti-interference.A design method of inner current loop based on two-degree-of-freedom type Ⅱsystem is proposed in this paper.Under the compromise between the fast response and anti-interference of the system,a simulation analysis is done under different freedom coefficients,through choosing freedom coefficient reasonably,it can not only increase the anti-interference performance,but also reduce the overshoot of the system.Finally,an experiment is carried out in the 11kW wind power generation system platform.The experimental results show that the proposed control strategy based on two-degree-of-freedom can not only improve the anti-interference of the system,but also keep the faster dynamic response,solving the problem of the gird-connected current low frequency oscillation.The effectiveness of the theoretical analysis and the control strategy is verified.