Further Improvement on Delay-Dependent Load Frequency Control of Power Systems via Truncated B–L Inequality

In this paper, a new method is put forward for the closed-loop stability analysis of PI-type load frequency control (LFC) scheme with interval time-varying delay. Improved delay-dependent conditions in terms of linear matrix inequalities for single-area and multi-area LFC systems are deduced by the proposed augmented Lyapunov-Krasovski (L-K) functional. Less conservativeness of our main results is due to an integral inequality called truncated second-order Bessel-Legendre (B-L) inequality, which can produce tighter bounds than Wirtinger-based inequality that encompasses Jensen inequality. Finally, the two-area interconnected power system based on Matlab/Simulink is provided to show the effectiveness and superiority of the obtained results.