Robust consensus-based secondary voltage restoration of inverter-based islanded microgrids with delayed communications

This paper proposes a robust distributed secondary voltage restoration control protocol for inverter-based islanded microgrid. The problem is attacked from a cooperative-based control perspective an inspired to the tracking consensus paradigm. The task is achieved asymptotically by exploiting only delayed communications among distributed generators, while dispensing with the knowledge of local models, parameters, and in spite of the electrical coupling due to power lines and loads. Robustness is obtained thanks to the integration in the control protocol of an Integral Sliding Mode Control term. The actual control output is continuous and can be safely Pulse-Width Modulated by a fixed given frequency, as required to not hurt the switching power artifacts. A dedicated Lyapunov analysis providing a simple set of tuning rules is given. A Linear Matrix Inequality (LMI) criterion is also employed to estimate the maximum delay for communications. Finally, simulation results show the effectiveness of the proposed solution.