针对饱和线性系统,借助二次型Lyapunov函数,估计稳定域的一个严格子集。同时为了减少保守性,利用矩阵的Schur补性质,将如何选取该二次型Lyapunov函数的问题转化为标准的LMI凸优化问题。将该方法应用于电力系统,提出一种判断饱和PSS控制是否有效的方法。其主要思路是估计出饱和系统的稳定域,通过分析预想扰动的状态量是否位于估计的稳定域内,从而为判断此饱和PSS控制是否能有效镇定预想的扰动提供判据,利用算例验证了方法的有效性。
A quadratic Lyapunov function is employed to estimate the stability region of a linear system with saturation nonlinearity. To reduce the conservatism in the estimation, the Schur complements of the matrixes are applied to transform the problem of selecting a suitable quadratic Lyapunov function into a simple convex optimization problem with linear matrix inequality (LMI) constraints. The method of stability region estimation is further applied to power systems with the saturated power system stabilizer (PSS), and a method is introduced to analyze the performance of the saturated controllers by checking whether the expected initial states of a power system resides inside the estimated stability region or not, Simulation tests demonstrate the approach is effective.