Voltage and frequency control of islanded microgrid based on combined direct current vector control and droop control

The increased integration of distributed energy sources into microgrids presents a major challenge in voltage and frequency stability of the microgrids, especially in islanded conditions. Microgrid control is typically classified into a three-level hierarchical control involving primary, secondary, and tertiary control, where primary and secondary levels are related to the operation of a microgrid itself, and tertiary level takes care of the coordinated operation of network microgrids. A key challenge associated with the microgrid control is how to maintain voltage and frequency stability in microgrid islanded operation conditions. This paper proposes to integrate a direct current vector control mechanism with the droop control method to overcome the challenges. Compared to the conventional control methods, the proposed method improves microgrid stability, relibility, and power quality. Simulation study shows the effectiveness and excellent performance of combining direct current vector control with droop control for islanded microgrids.