A Novel Scheme for Harmonic Load Sharing in Islanded Microgrids

In this paper, an approach based on circulating currents is proposed to compensate harmonic current sharing error among distributed generation (DG) units. A hierarchical control structure is utilized for implementation of the proposed approach. In this structure, primary and secondary controls are locally implemented for each DG. Unlike the conventional virtual impedance approaches, the effect of the proposed method on the quality of DG output voltages is smaller and the information of impedance of DG distribution lines is not needed for its implementation. Results obtained by simulating the system under study, verify the capability of the proposed scheme in improving load sharing.