基于多求和不等式输出反馈Lyapunov判据的时变时滞电力系统二次调频控制

Secondary Frequency Modulation Control of Power System With Time-varying Delay Based on Lyapunov Criterion of Multi-summation Inequality Output Feedback

电力系统使用通信网络进行动态调频时引起的时滞问题会对系统稳定性造成很大威胁。针对负荷频率控制中的网络化时滞问题,建立考虑时变时滞特性的负荷频率控制离散化状态空间模型。采用多求和不等式,构造一种具有低保守性的Lyapunov稳定判据来求解区间时变时滞负荷频率控制(load frequency control,LFC)系统的稳定裕度。在此基础上,推导时滞相关输出反馈增益的线性矩阵不等式(linear matrix inequality,LMI)准则来设计二次调频控制器参数。仿真结果表明,该文所提出的稳定判据能够求解更大的时滞稳定裕度,具有较低的保守性。所提出的控制器设计准则能够快速求解时变时滞下输出反馈增益,有效抑制小扰动下系统的频率振荡,使系统具有时滞稳定性。

The time delay problem caused by the dynamic frequency modulation with the communication network in the power system will pose a great threat to the system stability.Aiming at the network time delay problem in the load frequency control,a discrete state space model of the load frequency control considering the time-varying time delay characteristics is established.Using multiple summation inequalities,a low-conservative Lyapunov stability criterion is constructed to solve the stability margin of the interval time-varying delay LFC system.On this basis,the LMI criterion of the delay-related output feedback gain is derived to design the parameters of the secondary frequency modulation controller.The simulation results show that the stability criterion proposed in this paper can solve a larger time-delay stability margin with less conservative.The proposed controller design criterion can quickly solve the output feedback gain under time-varying time delay,effectively suppress the frequency oscillation of the system under small disturbance,giving the system time delay stability.