基于区域极点配置的风电系统弱阻尼低频振荡模式抑制

风电并网不仅影响原有低频振荡模式，而且可能引入新的模式。改善单个低频振荡模式，可能削弱其他模式阻尼。基于双馈风电机组详细建模，建立风电系统状态空间方程，选择控制变量和输出变量。考虑双馈风电机组出力变化，分析弱阻尼低频模式区域极点配置的必要性。兼顾电网原有及新引入弱阻尼低频模式，构建降阶模型。采用基于线性矩阵不等式的区域极点配置法，设计输出反馈控制器，将所有弱阻尼低频模式配置在设定区域，提高其阻尼比，并增加系统稳定裕度。算例分析表明，所设计控制器有效提高所有弱阻尼低频模式的阻尼，改善了风电系统振荡特性。

Suppression of weakly damped low-frequency modes of wind power system based on regional pole placement

Wind power integration will influence the existing low-frequency oscillation modes and possibly introduce new modes. Suppression of one single low-frequency oscillation mode may decrease damping of other modes. Based on detailed modeling to the doubly-fed induction generator (DFIG), the state space equations of wind power system are established and the control variables and output variables are determined. The impact of DFIG output is analyzed to reveal the necessity of the regional pole placement of the weakly damped oscillation modes. A reduced-order model is derived considering both the existing and newly introduced modes. The regional pole placement based on linear matrix inequality is applied to design the output feedback controller. All the weakly damped modes are placed within the desired region to increase the damping ratio and improve the stability margin. Numerical results show that the designed output feedback controller effectively increases the damping of all weak damping modes and suppresses the oscillation characteristic of wind power systems. This work is supported by National Natural Science Foundation of China (No. 51637004).