Distributed secondary frequency control scheme with A-symmetric time varying communication delays and switching topology

•A delay independent secondary frequency DAI control scheme for MGs subjected to time varying communication delays and switching communication network topology uncertainties is presented.•Fixed gain parameters of the secondary controller are made adaptive by using a Lyapunov Krasovskii based adaptive controller.•The control scheme also ensures the most economic allocation of the control inputs at steady state, which guarantees identical marginal cost. A distributed control of a Microgrid (MG) depends on the communication network for the exchange of information among the Distributed Generators (DGs). Most of the control schemes consider ideal communication among the DGs; however, in practical systems, delays are inherited in a system that can affect the dynamic performance and even destabilize an MG. Therefore, in this research work, delay independent distributed secondary frequency control for MGs is presented. Sufficient delay independent conditions for robust stability of the buffer-free Distributed Averaging Integral (DAI) control scheme is proposed while considering A-symmetric time varying communication delays and switching network topology. Moreover, in this work, slow as well as fast varying delays are analyzed using Lyapunov Krasovskii and Lyapunov Razumikhin's approach. Furthermore, a Lyapunov function based adaptive control approach is employed that updates the constant gain parameters to compensate for the uncertain or varying parameters. Finally, the efficacy of the controller is demonstrated through simulation studies that validate its performance in different scenarios.