Mixed Voltage Angle and Frequency Droop Control for Transient Stability of Interconnected Microgrids

We present a dissipativity-based control design for transient stability of voltage angle droop controlled interconnected microgrids, in scenarios where voltage angle measurements may be lost. In the absence of angle measurements from some microgrids, we show that indirect control via traditional frequency droop controllers can be employed in those microgrids to guarantee stability of the interconnection. We model this mixed angle-frequency droop control (MAFD) framework as a nonlinear switched system, and provide control design equations in the form of linear matrix inequalities to guarantee stability under arbitrary switching between angle droop and frequency droop controllers. We demonstrate the performance of this design on a test system of interconnected microgrids under conditions of measurement loss and load changes.