A Novel Grid-connected Harmonic Current Suppression Control for Autonomous Current Sharing Controller-based AC Microgrids

Since the power quality of feed-in grid current in a grid-connected microgrid (GCMG) can be influenced by a distorted utility grid, a novel feed-in grid harmonic current suppression control strategy is proposed in this paper. A feed-in grid current resonant controller-based harmonic compensation loop is integrated to the original autonomous current sharing controller. The feed-in grid harmonic current compensation loop that cooperated with the parallel resonant controllers in voltage control loop can effectively reduce the system equivalent output admittance at selected harmonic frequencies. Thus, the total harmonic distortion of feed-in grid current can be significantly decreased. Simulation and experimental results from a three-voltage-controlled-inverter-based GCMG verify the effectiveness of the proposed controller.