Further Improvement in Stability and Stabilization Margin of Micro-grid Load Frequency Control System with Constant Communication Delays

Abstract

AbstractIn this paper, improved results are presented for networked micro-grid load frequency control system integrated with electrical vehicle using the classical transcendental characteristic equation approach. In the system topology dealt in this paper, the centralized controller of the micro-grid system is connected to the locally synchronized distributed generation units through a communication channel. This architecture introduces a time delay in the feedback path of the closed-loop control system. The network-induced delay exerts a serious negative influence on performance and stability of the system. If the delay margin soars beyond a critical limiting value, called stable delay margin, the closed-loop system loses stability, and subsequently, the micro-grid system trips from the conventional grid. This paper presents improved results on delay-dependent stability and stabilization of networked micro-grid load frequency control system for a specified gain-phase margin and relative stability index. By employing a standard benchmark system, the analytical results are validated through simulation results. KeywordsMicro-grid systemsPlug-in electrical vehicleDelay-dependent stabilityLyapunov-Krasovskii functionalLinear matrix inequalityStability criterion