Predictive control of power flow between two islanded microgrids using nine-switch converter

Nine-switch converter has been recently known for its higher compactness with reduced switch count as compared to the back-to-back converter. The readily available dc-link capacitor made it an appropriate alternative for ac/dc/ac conversion in microgrids. Regardless of the complicated Pulse Width Modulation control scheme, this paper proposes a novel predictive power control for the nine-switch converter which is simple and allows concurrent control of real and reactive power flow between two islanded microgrids. The proposed control scheme adopts the virtual flux vectors and a newly defined reactive power to improve the power quality under the existence of grid voltage disturbances, i.e., voltage unbalance and voltage distortion. Simulation results of the proposed predictive power control guarantee decoupled active and reactive power controls, fast response, accurate power and dc-link voltage tracking, and sinusoidal current waveforms with low harmonic distortions under the various grid conditions.