调频双馈风电场机组的轴系扭振阻尼控制

Torsional Oscillation Damping Control for DFIG-based Wind Farm Participating in Power System Frequency Regulation

大容量风电场逐渐被要求参与电力系统调频，相应的辅助频率控制及风电场对电力系统频率稳定性改善的研究已比较充分，然而，相关研究很少考虑风电场频率控制对机组的影响。本文研究发现频率控制会恶化机组传动轴系扭振，从而限制风电场频率控制的实施。为解决此问题，本文提出基于无功调制的轴系扭振自适应阻尼控制。抑制轴系扭振从而使得风电场能够满足相关并网导则的要求。相比传统基于有功调制的阻尼控制，在达到期望的阻尼特性改善效果时，采用本文提出的方法需要的控制能量更小。此外，本文提出的方法能够有效改善因参数不确定性、工况变化或控制模式变化导致阻尼控制效果变差的问题。仿真验证了提出方法的可行性及有效性。

Large scale wind farms （WFs） are gradually required to participate in power system frequency regulation especially in a weak grid. Corresponding ancillary frequency control functionalities and the contribution of the WF to system frequency stability are well studied. However, the impact of WF ancillary frequency control on wind turbine generators （WTGs） is rarely considered. It is found in this paper that the ancillary frequency control deteriorates drive-train torsional oscillation of the WTG, which restricts application of the ancillary control. To overcome this problem, this paper proposes an adaptive damping control scheme based on reactive power modulation of the WTG to suppress drive-train torsional oscillation, which can assist the WF to meet the grid code requirements. Superior to the traditional active power modulation method, the proposed adaptive control scheme can achieve satisfactory damping improvement with less control effort. Furthermore, the adaptive scheme with a torsional frequency updating mechanism can effectively counteract torsional damping deterioration caused by parameter uncertainties, operating condition or control mode variations. Feasibility and effectiveness of the proposed damping control are validated by simulations.