Delay-dependent stability of DC Microgrid with time-varying delay

Abstract

In order to optimize the efficiency of renewable energy sources they are connected in a form of AC and DC Microgrids. Furthermore the increased number of DC loads has shifted the view to DC Microgrids. This paper presents the stability and maximum time delay calculation for a DC Microgrid implementing master-slave control strategy. The communication between the master and the slave is achieved through communication network which makes the DC Microgrid a time delay system. A stability criterion based on Lyapunov-Krasovskii functional and replacing the delay term by Newton-Leibnitz formula is used to derive a set of linear matrix inequalities. The binary iteration algorithm is used to solve the set of linear matrix inequalities and to calculate the maximum allowable delay bound. The effects of the voltage controller gains on the maximum allowable delay bound are also investigated. Further, the relation between the maximum allowable delay bound and the time delay variation rate is studied. The results are tested through simulation using Matlab/Simulink.