A DQ droop control strategy for fixed frequency VSI-based AC microgrids

The development of distributed energy resources, renewable technologies, and storage systems has given great importance to power electronics that enable coordination and parallel operations of multiple distributed generation units (DGUs) in microgrids. These DGUs are electronically-coupled to each other through power converters that can accurately control their output frequency. This paper presents a droop control technique for fixed frequency VSI-based ac microgrids that combines reference frame transformation, Lyapunov stability analysis, and a modified dc droop control strategy to share active and reactive power between the DGUs without altering the frequency and magnitude of the bus voltage in the islanded microgrid. The simulations show that the proposed distributed droop control ensures proper sharing of the active and reactive power, and regulates the bus voltage at the nominal value while operating at a fixed frequency.