Harmonic current filtering and resonance damping have become important concerns on the control of an islanded microgrids. To address these challenges, this paper proposes a control method of inverter-interfaced Distributed Generation (DG) units, which can autonomously share harmonic currents and resonance damping burdens. The approach employs a load compensator based on the decomposition of output current, in addition to the outer droop-based power controller, as well as inner voltage and current controllers. The load compensator consists of a virtual fundamental impedance loop for enhanced sharing of reactive power, and a variable harmonic impedance loop which allows to counteract harmonic voltage drops across the grid-side inductance of the DG inverter, and to damp the harmonic resonance propagation throughout a distribution feeder. Experiments on a three-phase microgrid are performed to validate the performance of the proposed control scheme.
Proceedings of the Ieee Energy Conversion Congress and Exposition 2012, 2012, p. 211-218
the Fourth IEEE Energy Conversion Congress and Exposition, ECCE 2012