提升双馈风力发电系统低电压穿越能力的跟踪控制方法

为提升双馈风力发电系统的低电压穿越(LVRT)能力,提出一种基于状态相关Riccati方程(SDRE)技术的网侧换流器(GSC)跟踪控制方法。并网导则要求风电场在LVRT过程中须注入一定无功功率支撑电压恢复,为了改进非线性状态调节器在无功支撑能力上的不足,针对双馈风力发电系统的GSC设计非线性无功功率跟踪控制器,并采用SDRE技术求解状态反馈控制律。在维持LVRT过程中直流电压稳定的基础上,该方法能充分利用GSC的无功功率调节能力,为电网提供无功功率支撑以避免电压恶化。最后,在Matlab/Simulink平台搭建9 MW双馈风力发电系统,并在三相接地故障下进行仿真验证,结果显示,所提出的GSC控制方法具有良好的暂态表现,能够有效提高双馈风力发电系统的LVRT能力。

A tracking control method for doubly-fed induction generator to enhance the low voltage ride through capability

In order to improve the low voltage ride through (LVRT) capability of doubly-fed induction generator (DFIG), a tracking control method for grid side converter (GSC) based on state-dependent Riccati equation technique is proposed. The grid code requires that wind farms should inject reactive power to support voltage recovery during LVRT. In order to improve the deficiency of the nonlinear state-regulator in reactive power support capacity, non-linear reactive power tracking controller is designed in GSC of DFIG, and the state feedback control law is obtained through solving state dependent Riccati equation. On the basis of maintaining dc link voltage stability in LVRT process, the reactive power regulation capability of GSC is fully utilized to provide reactive power support for the power grid to avoid voltage deterioration. Finally, a 9 MW DFIG-based wind farm is built in MATLAB/SIMULINK. The simulation results show that the proposed GSC control method has good transient performance and effectively improves the LVRT capability of DFIG through simulation verification under three phase ground faults.